I was hoping someone could confirm for me what I believe to be a failure in the internal governor mechanism on a Briggs and Stratton Intek twin, 20 hp.
Mower: Greenfields E2000 MkII.
Engine details: Family YBSXS 7242VF 274844 Model 406777 Type 000714YH
Basic question:
Should the governor shaft only have 15-20 degrees of movement when the arm is freed/removed? Does movement in excess of this mean the governor set up inside the motor has came apart/adrift/failed?
Details:
I had a carbie problem which was solved with a small O-ring replacement in the float bowl. I refitted all the linkages and springs (3) after much thought followed by some googling (which showed I had the 2 springs related to the governor arm- the governor spring and governed Idle spring, correctly fitted). There was one other spring that appeared to connect to the choke mechanism at one end and to the other a bracket secured by the bottom left hand side manifold bolt. This I am not sure of as there are no holes to which it could realistically connect (it's a fine spring), leading me to convince myself that the only possibility was to hook around the choke bracket that allows the cable movement (across the mower) to actuate the choke linkage (rod). I couldn't find reference to this spring readily. The carbie is a Nikki with one float bowl.
Upon restart the engine revved hard regardless of the throttle setting (I had connected it). Of course it only ran for a small number of seconds before I shut it down. Much thought and inspection led me to discover that the governor arm did not, unless manually turned anti clockwise, push up on the throttle linkage much, leaving it well short of the adjustment screw. If I started the unit manually holding up the throttle linkage, the motor ran as expected.
I felt that the third spring should be pulling back the arm such that the throttle linkage was up against the idle adjusting screw, but there are no indications as to this being possible.
Googling suggested the governor (internally) failed in these motors, and that checking the range of motion in the shaft (taking movement from the governor arm and passing into the engine) would indicate whether failed or not. I didn't remove the arm from the shaft, but as the carbie and bracket were easily removed, I was able to free the linkage allowing the arm and shaft a full range of motion (well, 90 degrees at least). The arm and shaft easily rotated the full range possible- close to 90 degrees.
If it is a governor failure, is it pure coincidence, or ???? I didn't put any pressure on the governor arm and did not slap it backwards and forwards etc etc.
To add to my woes, the starter motor plastic drive gear has become separated from the shaft after a failure of the securing clip/s. The replacement kits seem to be around $40 if I can get them, with a whole new starter motor not much more than $110 (or thereabouts). I'm led to believe that the starter is part 497595 (C clips distinguish these, I believe).
I am already thinking about taking the motor out and paying someone to fix the governor if that is the problem. I don't like the idea of having to remove the drive and cutter pulleys from the shaft (crank?). A quick look suggests this will have to happen before it comes out of the mower, but hopefully I'm wrong and someone can reassure me.
Hope it was right to start a new thread. Apologies for any etiquette I have overlooked.
First let us get the model and type corrected for parts look up. What you post for the type number is the date code which indicates that it was manufactured July 14, 2000. The type number is the number right after the model number and the trim number is right after that. These are usually found on one of the rocker arm valve covers.
As for the governor yes it possible for it come apart but not normally. More likely you just bump the static adjustment out of placed, The governor adjustment if not done right will lead to a racing engine and does take much either. What you need to do first is the static adjustment of the governor arm. If it still races after the following adjustment then it is a problem with the governor and someone would need to go in and replace it.
Static Governor Adjustment
1. With governor lever nut loose, rotate governor control swivel counter-clockwise as far as it will go (wide open throttle) and hold in this position. Note this must done with the carburetor and linkages installed. Throttle control cable removed.
2. Rotate governor shaft clockwise as far it will go, Fig. 20.
3. Torque governor nut to 130 in. lbs. (15.0 Nm).
Now the starter personally I never had a circlip (retaining clip) to simply come off unless someone had deformed it not how to remove and install it. Here I just replace the clip with a new one and install it the tool that brought for just installing these clips but they can be install without it just much harder to do. Good news as these starter drives are the same unless you got a very old engine where they use a pin to retain them. Even the ones with the steel gear uses the same starter clutch. There is one drive that is different but I have yet to see it here.
But once we have the type number we can get right part number(s) that you would need for replacement parts. Also note aftermarket starters for these are available so don't need the OEM starter which can be expensive.
Corrected information re engine (removal of light corrosion revealed the full Model, Type and Code):
Family YBSXS 7242VF 274844 Model 406777 Type 0138E Code: 000714YH
I will indeed do as you suggest, AVB, but I should point out that at no time have I separated the governor lever from the governor shaft. The governor nut (I assume this is the nut and bolt that clamps the lever onto the shaft as shown at the bottom left of figure 20 above) has not been undone until yesterday, and even with it loosened, the arm grips tightly to the shaft. Does this info change anything with regards to your advice?
I am still interested in verifying whether or not the degree of shaft movement is a valid method of diagnosing governor function.
Thanks again AVB. I will get the starter sorted, then get onto the governor diagnosis. I thought all the c clip style starter gears and clips looked the same, but most were only listed as suitable for single cylinder or up to 19 hp. I hope my local dealer has some in stock. The grass is going crazy here in New South Wales.
Sometimes removing and re-installing can change the setting due to amount play around the mounting screws or studs. It doesn't take to throw off especially if things are worn. Basically you do static adjustment and if you still have problem you go in and physically check the governor.
As degree of movement I have never heard that test in 10 yrs of servicing these engines. Now it might be valid if the governor push pin becomes dislodged but that would take the cross over shaft being fully ccw allowing the pin to fall off. Of the governors that I seen fail usually one of the flyweights goes awol. Now I did have one Kohler governor last year that the push pin was off but someone else had already been working on the engine a few years before me and had the mower in the bushes as having a dead engine.
As for the starter it is listed as pn 795121 Motor-Starter (4-3/8" Housing Length for Aluminum Ring Gear Only) superseding PNs 691262, 494990, 494198, 394943, 490420, 499521 and 497401. These numbers should help finding a suitable starter. I don't have that particular starter in stock here so I can't physically compare it to the more common one that fails here. I do see the specs is for 4-3/8" housing where the single cylinder starter I have here are 3-3/8" which means the 795121 would have more torque.
Actually I only seen a couple failures last year on Briggs single cylinder engines. I did replace several Kohler starters for worn out bushings.
Grass here isn't growing considering I am in for 1-3 of snow if changes over and don't comes down as freezing rain by morning. Then we going be below freezing for at least 48 hrs. Actually around 10-20 F.
Last edited by AVB; 29/01/1905:50 PM. Reason: cut and paste format correction
Starter fixed. Spare parts from local mower shop. Mechanic says these motors can have a decompression failure that can break the internal governor mechanism (plastic?) by pieces striking it. I'm hoping this isn't the case with mine. I better drain the oil and see if there is any evidence of failure. If none, I will reassemble and try to adjust the governor unless advised not to.
The 790562 doesn't have an ACR on it, provided the online images are correct. Now the one that the shop was thinking about is probably the 793880 camshaft on the 28, 31, 330000 series that does have an ACR that is prone to failures and it can take out the governor.
Any way let me know what you find to be the problem as it might something I need keep in mind if I run across this.
That's good news (I think). To be fair to my local mechanic, I spoke briefly to him about Intek 20hp motors and potential governor failure without talking specific model and type numbers, so he wasn't to know my engine wasn't fitted with an ACR. I didn't realise there would be models with and models without a feature like this. It's now raining at our place after days of high heat and humidity, so until I fix the ride on, it's back to mowing a couple of acres by hand. At least it keeps me fit.
If I attempt an adjustment of the governor (as per suggestions above) and then start the motor, do I risk damaging it if in fact the governor has had a failure (internally)? Should I drain the oil to look for evidence of failure before doing anything else? I assume there would be some pieces visible in the oil if it's broken?
I would be happy to take the mower to the local repair shop, however they have no room for any more ride ons, so to get it looked at in the near future, I'll probably need to remove the engine and take to them. Hence I'll keep at it myself for the moment.
Thanks for assistance to-date AVB. I will keep everyone informed as to the outcome of my investigations........
Wilbur, mowing a couple of acres by hand, what are you doing that with? Just reading your original post a 20hp on a Greenfield seems a bit of overkill isn't it. One problem with taking the mower to the dealer to get the motor stripped to repair the governor will quickly cost as much or more than buying a replacement motor. Something just to be aware of. If they are that busy it would probably take some time to get it repaired and you will be spending hours cutting that area by hand, new motor put it in and you are back cutting again
I didn't realise that if the governor is indeed shot, the repair costs could be so high. I had briefly looked at the cost of a new motor in Australia, and it seemed I would be paying around $1600 for a similarly sized Briggs motor (I think the costs may be significantly lower in the US, but I'm not certain).
It may be that the 20hp motor is overkill, but I am on relatively hilly country and thought it better to err on the side of a bigger motor when buying secondhand. I know that Greenfields of similar cut (32 or 34 inch) were fitted with motors as small as 13hp or smaller, so you may well be right. I will look at the cost of something a bit smaller......
Money is an issue, and I've always tried to do my own repairs as a result (and because until recently the repair shops in my area that would work on a ride on were hopeless). Similarly, I have had drive and deck problems that I think I have sorted, so have been reluctant to invest heavily in a new motor until the unit has proven itself. I am, though, nearing the point of needing to spend significant money to solve my mowing dilemma one way or another.
Wilbur, you should be able to pick up a Chonda 16hp for about $600 from memory, the 13hp are around the $400. That sort of money can very quickly be gobbled up with labor cost once you start removing the motor and stripping the motor down to repair whatever is wrong inside, and then we had to fix this and that while we had it apart
I'm sure you are right, and that's partly why I've always done what was needed myself. That, and the low quality of work I have experienced when I have paid. And just hating not knowing enough such that every time your mower doesn't start, you have to take it for repair.
Just to punish myself, I think I'll probably remove the engine and see how hard it is to get to the governor unit (unless I can achieve success through adjustment). I'm a glutton for punishment.
A Chonda isn't a bad idea, but I have been exposed to the negative press about them. Having said that, a new Chonda is the most likely outcome. I'm still hopeful though, that what I read about the extent of the governor shaft being indicative of a problem is wrong, and I'm just being pessimistic.
I'll attempt something this weekend. After I've finished mowing the 2 acres.
wilbur i was a bit concerned about all the bad talk on chonda's but i also read good reviews,i recently bought a 17.5 hp jono and johno chonda and it purrs i only have 6 hours on it but $550 delivered hey!...cheer's
Thanks GML for your input. Jono and Johno were unknown to me until you mentioned them. Currently they have 17.5hp motors for $550. Looking more and more likely to be an affordable solution should my motor have done its governor. Speaking of which, I thought I would include a link to the forum in which one contributor states that more than 15-20 degrees of governor shaft movement (after governor arm is removed) is indicative of failure, specifically related to 20hp Briggs and Stratton Intek motors. If true, it is a worthwhile diagnostic tool, I would have thought.
Wilbur, nothing to loose once you have pulled the motor to split the cases and see what has gone wrong inside, then you can go from there, you might be able to salvage it. It is when you have to pay somebody to do it that it quickly becomes a non event. Jono and Johno are good, they have a big range of farming stuff.
Ok, governor adjustment attempted. This is what I found/learnt,
1) with the governor arm nut loosened and the shaft rotated, initially I was heartened to find the range of rotation was about 20 degrees. From this I can only assume that the extended range I experienced earlier must have been the arm slipping on the shaft (although it appeared to be tightly connected it may have been slipping because I had assumed that the arm was not attached to the round part of the shaft, but was connected to the shaft as it appears at the very end, that is shaped like an allen key, flattened off, and thus only allowing discreet positions. AVB had indicated by his instructions that wasn't the case, but I was not clever enough to interpret this fully)
2) I performed adjustment as per instructions provided by AVB
3) motor still raced
4) I checked the adjustment and found the motor still racing
5) I manually held the governor arm such that the motor didn't race and in so doing could hear and feel an occasional knock coming through the arm
6) I then loosened the adjustment nut to gently check the governor shaft range of motion, which was the 20 degrees or thereabouts but then reduced as the shaft seemed to jam in position. I applied a small amount of force to see if it would free up, but to no avail
So now I suppose this is evidence that the governor has failed, but would be interested if anyone could answer the following questions for my better understanding of the issue.
Q1) With the engine off and the throttle in idle position, my throttle linkage sits such that the throttle is no where near closed. Is this how it should be?
Q2) Does the governor mechanism act against the pull of the springs when the motor is idling to push up on the throttle linkage and bring it hard up against what I assume to be the idle adjustment?
Q4) I have a third spring that is connected to a small bracket attached to the engine by the bottom inlet manifold bolt on the left of the mower when looking from the front. I have attached it to the choke linkage arm such that it applies a small amount of force to return the choke to open, but not enough to actually pull it away from closed position. I can't see anywhere else for it to attach, try as I might. Can anyone confirm for me that this is the correct placement? I was hoping it would attach to the governor arm and pull it counter clockwise such that the engine idled, but just can't see any option for that to happen. The spring isn't long enough to reach the arm without it being really stretched tight, and there is nowhere for it to attach.
Q3) If I manage to get the engine out of the mower frame and remove the pulleys from the bottom of the crankshaft, is it possible to remove what I will call the sump and attempt a replacement of the governor internal mechanism, or is it a nightmare job requiring specialist tools? (I have torque wrench and tools to attempt most mechanical jobs perhaps other than full rebuilds
Thanks in advance to anyone who can offer advice or opinion on any of these issues.
PS I've tried to attach photos but see no evidence of them appearing on my preview. Hopefully they will appear in the actual post, and not in a position that renders them useless.
Norm, I just realised you posted info that answered a question I just asked in my last post- (should I proceed and attempt a repair?). I must have been working out how to attach photos while you were typing.
Hi Wilbur, I will try to answer your questions but it seems like the governor has failed. Questions 1& 2 throttle should be wide open with the motor stopped as soon as it starts the governor should close the throttle Question 3 removing engine can be a pain if the pulley doesn't come off easily, pulling, after that it is just nuts and bolts Question 4 don't worry about the choke at this stage, it has nothing to do with the problem at the moment
Norm, engine coming out now. I live in a rural area that still has someone who fabricates, and repairs all sorts of machinery and equipment. He has the equipment necessary to get the pulleys off, I should imagine. Oxy, gear pullers far superior to the cheap versions I own, and other methods of persuasion.
Wilbur, to remove the motor, drain the oil and petrol, remove the battery and tip the mower over on its side, then you can get at everything and see what you have to do
Ok, motor out, pulley off (slid of with only hand strength needed). Cases split. Photo 1 shows what I found. When lifting the motor out, I'm pretty sure I heard the components cluncking around in the bottom case, so I think it had come apart and caused my problem. I suppose I have to hope so.
Photo 2 is a closer look at the loose components. I can't see any evidence of a problem, although I don't know what holds the pieces together if the bottom case doesn't hold them up.
Photo 3 shows the end of the shaft of what I assume is the governor unit. Not sure what it should look like really. It is flattened, but not crisply.
So, how do I proceed from here?
Is where I found them irrefutable evidence of failure?
Norm, I managed to do it before your advice came through, so I didn't have the benefit of your suggestion of tipping mower. It wasn't too bad doing it in upright position, but more time consuming I guess. A worthwhile tip for the next time (hopefully not too soon).
Wilbur, well at least you know it had to come apart. From here I think you will have to wait for AVB to come along as he is the go to man on this Briggs stuff
From you have done does indicate a failed governor. And no it doesn't take special tools to do the work though you might need clean the crankshaft PTO end so slips pass the seal and bearing surface of the cover. A few I ran into with rust.
With feeling a bump while holding arm makes me think the governor gear is stripped or you have a sheared key on the crank gear but you will not know for sure without going in and looking.
I posted this before realising the thread had gone onto page 2, so I thought I better repost here. Hope this is ok
Ok, motor out, pulley off (slid of with only hand strength needed). Cases split. Photo 1 shows what I found. When lifting the motor out, I'm pretty sure I heard the components cluncking around in the bottom case, so I think it had come apart and caused my problem. I suppose I have to hope so.
Photo 2 is a closer look at the loose components. I can't see any evidence of a problem (other than the weirdly shaped hole in washer), although I don't know what holds the pieces together if the bottom case doesn't hold them up.
Photo 3 shows the end of the shaft of what I assume is the governor unit. Not sure what it should look like really. It is flattened, but not crisply.
So, how do I proceed from here?
Is where I found them irrefutable evidence of failure?
Norm, I managed to do it before your advice came through, so I didn't have the benefit of your suggestion of tipping mower. It wasn't too bad doing it in upright position, but more time consuming I guess. A worthwhile tip for the next time (hopefully not too soon).
Well that looks like it kill it and I hate to be the bearer of bad news.
The shaft sticking out of the governor is should to be pressed in place right below number one cylinder as shown the image below. The problem is that this early model engine crankcase is NLA; therefore , you would need a new engine. Red circle stud, Orange square bad spacer washer
Ah well, such is internal combustion engines. It's such a pity when something seemingly minor sends an engine to the recycling area at the tip.
So as a summary for anyone in the future experiencing governance (is this the correct use of the term) problems, here's my take on it (although I could be wrong and would be happy for anyone to correct me). Similarly, I don't know the right names for each of the parts we are talking about here. For instance, now I see the set up, using the term governor shaft is ambiguous at best. I have made up my own terms in an attempt to clearly distinguish between parts, but if there are correct terms or better terms, please correct the record.
SUMMARY:
1) excessive range of rotation of the governor shaft probably is a diagnostic tool
I really think that, despite what I said earlier, that the 90 degree rotation of the shaft initially was real and symptomatic of the type of failure I experienced- UNLESS my understanding of how the unit is set up is wrong. The governor gear shaft somehow came free from its pressed connection into the upper case, fell to the bottom of motor, allowing the governor arm shaft a wider range of rotation. The reduced motion I experienced later was because the displaced pieces got in the way of the lever on the end of the governor arm shaft.
2) no evidence other than the racing motor was apparent- no metal in oil, no obvious performance problem upon start up.
3) the fact that this problem arose immediately after carburetor repair was pure coincidence, as was the starter motor problem
4) 630 hrs of operation before failure
630 on the clock- no guarantee this is the original motor). I can't speak for the maintenance schedule of the previous owner, but in the short time I have owned it (probably on 50 hrs of operation), I have routinely changed oil and filter, with little else done to motor. I hadn't adjusted valve clearances or anything similar. I have been too busy fixing the drive, perhaps unnecessarily.
QUESTIONS (AVB?)
1) so if it were possible to somehow attach the governor gear shaft in the upper case it may fix the problem (if only temporarily)?
2) does knurling the shaft actually raise metal on the high spots? This would effectively increase the shaft diameter, and thus potentially allowing a refit?
3) what about having a new shaft made up, slightly oversized where fits into case? Would need to drill out the hole to accommodate.....
4) is there any other way of permanently joining the shaft to the case, even if it only brings limited extension to the life of motor?
5) what actually happened here?
The shaft somehow became loose by the hole in case becoming elongated or something similar? The shaft itself shouldn't wear because it's just a press fit?
Next, the arm on the end of the governor shaft that can push up on the governor gear shaft when fully rotated counter clockwise doesn't hold the gear assembly in place and there was room for it to fall into the bottom case?
6) Is this a common internal failure?
We have spoken of the decompression valve failure that can lead to governor failure, but mine has no such set up. Is this an Intek specific problem? Twin cylinder v single?
7) Is there anything that would hold off a failure like this?
8) If I install a single cylinder Chonda, I imagine there will need to be significant throttle and choke cable re-engineering, fuel line modification and electrical work done. Anyone got any experience with this? Easy? Difficult?
AVB, do you think it might be able to be held in place with one of the Loctites. I remember fitting loose cam spindles in an Enfield, think I used 620 but the other end of the spindle was supported in the timing cover so flexing was not an issue. What is the damaged washer, is it just a thrust washer up against the case. Any thoughts as to why the hole would get damaged like that, seems a bit odd.
A lot good questions which I don't answers for. But a few I can answer though.
Yes knurling does raise the shaft metal effectively increasing its diameter. Here I use it on spindle shafts where the ID of ball bearing is slipping on the shaft journal. This slippage actually wears out the spindle shaft bearing journals. Also years ago it was a way to repair bad valve guides in automobile engine when they had none replaceable guides.
An oversize shaft would work but how do you get the right size circlip to hold the governor on the shaft or how to position it retaining groove on the shaft? A machinist could copy the profile to the new shaft.
Why it came out may be caused excessive heat expanding the aluminum crankcase. Just don't know here as it is the first one I have seen or heard about in my 10 yrs of working on these Briggs engines.
The problem with thought on the governor cross shaft holding things in place is that the push pin moves in and out allowing a loose shaft slide out of place so I don't think it hold position if just place back in loose.
The ACR problem I have seen all have been on the Briggs 28, 31, and 330000 series using the 793880 camshaft. Of course ACR do fail on other brands too just as obvious as the Briggs.
I think you was just the unlucky user to have this happen to. I haven't seen service bulletins indicating this a common failure either.
Now Norm personally I don't trust Loctite or an epoxy is this setup but someone with more experience might know of something or method that would work. The washer serves both as a thrust washer and way for oil to get upper part the governor assembly. As for hole damage I have no idea unless got damage as the governor failed.
I'm just the kind of guy to not let go of this problem until proven irreparable. Hence I'm prepared to entertain the idea of a repair, particularly as I can access lathes and operators at a reasonable cost and sympathetic to repairing rather than throwing out. Having said that, we are nearing the end of this Briggs adventure.
I haven't fully checked out the governor gear unit but understand that there are two parts to the shaft, allowing sliding to occur, effecting a change in position of the pivoting counterweights.
I have refitted the governor gear unit in top case to assess hole enlarging. It is certainly loose, sliding in and out freely, in fact with no resistance. Having said that, with the shaft fully inserted the play at the end of the shaft (bottom of shaft protruding below gear) is less than 2mm I would have thought. That would equate to less than 1mm (approx) of play at the opening of the hole.
Would knurling have a chance of picking up 0.5mm all around the shaft?
Would the gear apparatus need to be taken apart (I suppose counterweight pins would need to be ground off) for any machining to be done?
If and when the enlarged hole is made uniform by drilling out, I'm wondering what sort of tolerances need to be thought about when considering gear engagement. I would hope that it might be possible to drill out carefully, with the new hole being centred well enough for those tolerances to be at least not an immediate problem. Tight gears would obviously be a problem. Is suppose this strikes at the heart of whether or not that part of any attempted repair can happen without further stripping of the motor. That would be it for me.
As always, thank you for your advice and opinions. I have learnt a lot, and at least tried to avoid being part of the throw away society in which I live. Sharing knowledge and experience online is a great thing. I hope this thread can be of value to others.
Wilbur, this is not just an easy fix up, no drill to go near it. I'm not 100% sure what you are planning but if you plan on opening the hole and getting an oversize pin made, this is all work to be done by a very experienced machinist. The case would need milling out and an O/S pin made to suit. Finding somebody who can do this work is not easy. Then the cost quickly starts to add up and at the end of all this you still have an old engine
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