OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Briggs & Stratton 3.5 over revs

Hi all,
I know this subject has been done to death and I have researched the replies here but I am still having problems. I have an old Victa Vantage with a B&S engine and a pulsa jet carb that I got from the trash. All it needed was an adjustment to the kill wire and all went well so I decided to clean it up, repaint etc. I removed the carby and engine and did up the base and then replaced everything. Now, when it starts, it goes to full throttle. I had full throttle control before I interfered with it so it must be something in the reassembly. I klnow the throttle spring is dodgy and I have a couple of mowers with the same engine so I replaced the springs on the carby with springs from the another mower to test that but the same problem appeared.The throttle cable seems to function properly....What else could it be? Any ideas? Could it be sucking air somewhere - would that do it??

With the engine stopped, move the speed control lever from Stop to Max (tortoise to rabbit) while watching the lever on top of the throttle butterly. Does the throttle move from against the idle stop to wide open? If it doesn't, the governor is in disarray. You may have connected the springs incorrectly, or it may be a disconnected or kinked speed control cable, or even more likely, a bent or disconnected wire link on the governor itself. When you remove the carburetor you have to disconnect that link, then when you reconnect it, it is easy to put it on incorrectly so the throttle is jammed open.

Hi Grumpy,

It's nice to talk to you again. Thank you for the reply. I think you're correct it HAS TO BE the throttle linkage somehow. Tomorrow I'll buy another spring and have a good look at the things you've suggested. I'll let you know how I go. I'll try and post some pictures - before and after.

Thanks sparker, pictures are by far the best way to communicate on problems like this. They also make a much better archive. Please include top views of the governor base plate with the speed control at both maximum and minimum. That should show us the lever positions, whether the wire link it working properly, whether the springs are in the right places, and what the throttle butterfly is doing.

Hi,
Here are some shots I took; The throttle is fully open (off position). I bought a new governor spring ($13.25 here in Mackay) and have added it to the carby. There is a shot of the old spring if you can call it that! However, to no avail as the engine still races away to full throttle. If I manually move the governor it works OK. I notice more tension than I thought would be there on the governor but can't figure out where it is coming from or whether that's normal. Do you think a good clean of the carby would make a difference? I found this on the web it is to do with the governor setting - it might help someone but it did'nt help me:

The Following is an Instruction File I Made for Setting the Governor Arm Correctly. Any Input is Appreciated.
>>If you Removed/Loosened the Governor Arm from the Governor Shaft or Put the Linkage in a Bind when the Carburetor was Removed, then Reset the Governor.
>>**To Reset the Governor; Loosen the Governor Arm Bolt and Turn the Governor Shaft Clockwise Until it Stops.
>>Using the Governor Arm Hold the Carburetor to Full Throttle. Now with the Shaft Full Clockwise and the Governor Arm and Carburetor Held at Full Throttle, Tighten the Governor Arm Bolt.
>>If the Engine Still Runs Full Throttle, then Reverse the Rotation of the Governor Shaft, but Still Hold the Carburetor at Full Throttle with the Governor Arm.
>>**If it Still Runs at Full Throttle, then Check the Internal Governor.**

sparker, those instructions appear to be for an engine with an internal governor, not an air vane governor. Here is what your governor linkage should look like:


As you can see, the diagram of how it is supposed to be, doesn't look much like what you have done at the moment. The governor spring and governor link both seem to be incorrectly connected. The left end of the governor spring should be connected to the hole in the end of the air vane lever, along with the end of the governor link, and the other end of the governor link should be connected to the throttle butterfly.

Hi Grumpy,
Thanks for the input. I don't think my photo's are as clear as I'd like. I have now tried a close up of the area but it's a little blurry and the second one you'll have to turn your monitor upside down. I have the long governor spring (and the smaller spring - not on your diagram)connected to the "eye" of the steel linkage. The linkage is connected to the governor vane at one end and to the throttle at the other end. I think that's the correct position but whether their doing the job....??

I changed the carburetor-no difference. Linkage wrong somewhere? something else? Could it be the breather tube from the crankcase to the carburetor - it is loose and won't screw into the fully tight position and still be able to get the boot to the carby on. Could it be sucking air there? That may sound dumb but don't forget who you're dealing with!

sparker, I can't really find the link that goes from the air vane lever to the throttle butterfly in your pictures, but if you are sure it is there, that is fine. What I do see, and you have mentioned yourself, is a second governor spring that the diagram does not show. I previously had taken this to be the missing link, incorrectly installed.

Does the throttle close when you push the vane away from the flywheel? If it does, but it takes more force than the vane can provide, it sounds like too much spring force. Since you have two springs, where the manual says you should only have one, I suspect you need to remove that small spring that isn't shown on the diagram. Perhaps some previous owner put it on there after he trashed the proper spring, which you have now replaced? It's like when you own a block of flats, sparker: the main problem you always face, is the "tenant's improvements" that don't improve anything, and have to be put back as they were in the first place.

I think the two springs are a later model carby. Here is a shot I stole from another site showing a clear view of the linkage arrangement. That's the same as mine but...it's not working for me. Any thoughts on the breather tube theory?

When the vane moves away from the flywheel, does the lever attached to it foul the breather tube?

No, there's no fouling and I was thinking about it sucking air into the crankcase from that tube and realised that it could not possibly be the problem. It's got me stumped.

Let's try to look at it from first principles. When you put the speed control at minimum, does the throttle close? With the speed control at maximum, if you apply light pressure with one finger to move the air vane away from the flywheel, does the throttle close?

With the throttle at minimum i.e. the stop position (when the coil shorts out on the carby base) the throttle is in the fully open position-just like the picture above. Doesn't sound right does it? Moving the throttle cable makes no difference to the butterfly but changes tension on the springs, I guess so the governor vane can take over.

And yes, If I start the engine and manually move the vane it will control the engine speed. Grumpy, thanks for your help. I am going to sleep on it and have a go tomorrow. If you think of anything let me know.

sparker, something seems to be keeping the vane from moving freely. I suggest you temporarily remove both governor springs, then try to move the vane with very light finger pressure. If there is any resistance whatever, the vane or linkage is physically stuck. Disconnect the link between the air vane's arm and the throttle, and see if the vane is free. If it is, your link between air vane arm and throttle was stuck. If the vane isn't free, loosen its pivot bolt and see what is causing it to stick - the pivot bolt might be too tight.

With regard to your earlier comment that the use of a second governor spring is on a "later model", and therefore applicable to your engine, there seems to be a mismatch of information. As far as I can tell your ignition coil does not have the Magnatron fitted, so your engine is pre-1982.

Post-Edit: I was wrong, the ignition coil is clearly a Magnetron, so the engine is post-1982 (unless the Magnetron had been fitted later).

The one you showed with the second governor spring has a Pulsa-Prime carburetor, not a Pulsa-Jet like yours, and is therefore at least ten years newer than yours, probably more than that. This makes it seem unlikely that your engine had that second, small-diameter governor spring when it was new, or that it should have it now.

Grumpy, that carby appears to be one of the plastic ones, correct me if i'm wrong here, but didn't briggs use metal carby's till quite recently?

Again, i could be very wrong here, Briggs engines are still new to me!

No Ty, that early plastic carburetor (which they called Minion) was used from about 1980. My 1982 Briggs 92508 has one, unfortunately. Mine hasn't given any trouble, but they were prone to distorting so things didn't fit together well. It's probably a good idea to avoid dismantling them, if you get the choice. The metal versions were more desirable, and more popular, and I think the Minion was discontinued after a few years but I'm not sure.

Ah, there you go. Thanks for that Grumpy, you learn something new every day.

I have seen the two spring setup, but it was on a 2006 engine, like the Pulsa Prime above. Out of curiosity, what engine is it you have there sparker? can you tell us the series of numbers stamped on the cooling cowl?

Grumpy, I believe you nailed it. The "tenants" must have at some point changed the linkage bar. I just happened to have an older style bar that only had provision for the one spring and thought I'd give it a go. The mower purrs like a kitten now instead of screaming its head off. I don't know what the difference is that it made but I'm not complaining - Thanks for your patience. Hi Mr. Davis that's a scary icon you have there - the engine number is 98902 2064 P1 01091954. This place would be lost without you guys or at least I would be. Bad photo's of the two linkages;

Glad you got a result here sparker.

I am a little confused by the engine number, Grumpy, perhaps you could shed some light on this, 09902 seems like a verry small engine to me, maybe it's 89902? or 109902? and the stamp has just misfired?

Or is there a 09902?

Sorry, I initially typed the wrong number. It should be 98902 2064 P1 01091954

Ah, 98902 seems better to me, Cheers Sparker!

That means it was made on 19 September 2001, so I don't know why the coil looks like an old one to me. One possibility is that it doesn't have the original air cowl. Does the starter cord pull up vertically or horizontally, sparker? Pre-Magnatron vertical crankshaft engines had vertical pull starters. (So did the first few years of Magnatron ones). If the air cowl is correct, I'm unfamiliar with the ignition coil it has - which isn't important but may be interesting.

Post-Edit: The coil is a Magnetron, as noted in a previous post-edit. And I should have known the engine had a conventional recoil starter, not a vertical pull. For normal recoil, the model number ends in 2. For vertical pull, it ends in 8.

Meanwhile I'm glad that is sorted out. It is nothing unusual with second-hand mowers, sparker, for the problems to be due to the tenant's improvements. It is one of the things that keeps us on our toes.

Grumpy, even if it does turn out to be something you are unfamiliar with, you still managed to find the fault and get him running! Good Job!

Sparker, if you could help us with our curiosities of your engine, is it possible you could post a few pics of the whole mower, and a few of the engine from the sides, back and fornt?

Sure, no problem but you'll have to excuse the crappy paint job. I was really disappointed there. Normally I'd use a hammer finish spray paint. This time I thought I'd use some old paint i had lying around which was close to the original blue but it is far too soft and scratches easily. here ya go!-

Thanks for that sparker, Just had a look through my records, and it seems i have a 2003 Victa Charger with a Briggs 98902, so when i have the chance, i will get a couple of pics up of its linkages, for reference skae.

However, even if my mower tells a different story, from the sound of it, Grumpy's advice has served you very well, so i would be hesitant in changing anything unless further problems arise.

I'll get some photo's up when i can, i may have already posted a thread about mine, if i find it, i will add it to this.

___________________________________________________________________________________

Heres one i forgot i had picked up the other day:



And here is the charger, Although its not a great angle, the second pic in this thread Seems to show only one spring, confirming Grumpy's comments.

I will get some better pictures up here at some point.

Grumpy, you have got me very curios about the 80's minions, could you post a few pictures in the gallery if you have one?

On the contrary, I think I can see a second spring in the hole near the governor cover. Doesn't matter anyhow now, as you say. That mower is identical to mine except for the colour and name. Even the stickers are the same.

You may well be right, i missed that little line there.

But as i said before, I'm fairly new to brigs, This is really grumpy's field, and wether his fix is factory original or not, it sounds like it has worked, which does not surprise me, He knows these engines pretty damn well (apparently even the ones that he dosent know )

Unless you are going for perfect original (and I'm yet to see somone keen on doing a full detail resto on a 2001 Vatage!) then yes, if it works, then it works!

You're absolutely right! I spent two days trying to figure what the hell was wrong (and I still don't know for sure) but it's working perfectly now as a result of Grumpy's thought train, and that's all that counts

Ty, I'll have to get my spare mower out of storage under the house to take pictures of its Minion carburetor. Meanwhile here's some technical detail:
http://www.tpub.com/content/recoveryvehicles/TM-5-4240-501-14P/css/TM-5-4240-501-14P_105.htm

I'm still not clear on that coil in sparker's mower, it looks like a pre-Magnatron one, but it can't be because it would require the base engine to have points.

My current suspicion is that sparker's engine had a home-made governor link that simply refused to pivot at the butterfly end, and jammed the linkage.

Thanks for that Grumpy, no rush for the pictures, just next time its convenient.

I will make sure to get a look, and a few pictures, of the coil on mine, and see if we cant find some answers.

With there later electronic Ignitions, have Briggs moved to a transitorised coil, or do they use a seperate coil and ignition module.

This looks like it could be an electronic ignition module to me:



What is it?

Yes, it's electronic. There are not any points.

Ty, Briggs moved to an all-in-one ignition unit (Magnetron) in 1982 and haven't used points since. The unit replaced the coil - it was a coil with a little electromagnetic sensor attached to it, to trigger the ignition as the flywheel magnet passed by, so no points were required. It can be fitted to older engines without modification of the engine. I'm not familiar with the appearance of the later electronic units - the original Magnetron was electrically rather crude, though they seem to have been reliable. sparker's unit looks just like the early coils, but doesn't seem to have the external Magnetron sensor attached.
Post edit: the ignition unit in the picture is a Magnetron, and the electronic unit is the black part which Mr. Davis has circled.
Perhaps they made the device more compact. Anyway, all of them look the same: same coil, attaching to the engine in the same place, and in the same way. The only change was in how the coil primary was triggered.

Ok, that's a bit differend to what I'm used to seeing, When Victa moved to electronic ignition, they used the same coil, but replaced the points with a module that controlled the timing. I imagine with the Victa module, it operated by the pulse from the coil itself, as the magneto passed. It was certaily not close enough to the flywheel to sense the movement itself.

In recent years, this moudule has been moved, and is now cast inside the form of the coil, creating a square plastic lump. i have also seen this with a number of brushcutter coils, thoug i imagine some of them would also use the system you are describing with briggs.

I could specuilate that the victa version is cheaper, as it seems to be adopted more widly by manufacturers as they move to China, however, the above engine pre-dates Rovers move to china i think, so that would not reflect on it.

I'm getting really curios now, so tonight I will try and check under mine, hopefully what i see there is the same, and i can pull it off and get some good shots and any markings noted, and post them up.

Ty, these 3 pictures are of my 3 May 1983 B&S 92508. It has a plastic (Minion) VacuJet with automatic choke, and the original version of the governor we have been talking about in this thread.




The third picture shows the coil. It is a very late points-type coil - I thought they changed in 1982, but it appears it must have been a bit later.
Post-edit: The coil in the picture is a very early Magnetron

Thanks for that Grumpy, I'll have to have a look through some of my recent donations from that era, Looking at the records i have with me, i dont have a 92508, but I have a few models from 1980 - 1988, so maybe one of thos may have one.

Since i have branced out, I have been trying to get my hands on as many different engines, and carby's as possible, to get my experience up and work out as much about the engines, and thier histories as possible. So if i dont have a Minion yet, i now know what to look out for!

With the coil, is it possible there was an overlap, maybe they started relesing the magnetron on some models in 82, and ran the points out till the next year on others?

Ty, a 92908 (i.e. basically the same engine with a PulsaJet instead of a VacuJet) from the same period was likely to have a carburetor made from Minion plastic, it wasn't only the VacuJet.

On the introduction of the Magnetron breakerless ignition, note that there is an official B&S way to retrofit these to breaker-point engines:
http://www4.briggsandstratton.com/miscpdfs/RNT/magnetron_retro-fit.pdf
Joe Carroll's way seems quicker and easier.

I have only found vague references to the changeover date to Magnetron on the internet. Some say 1982, some say it was mostly done by 1983, and some say it happened progressively over quite a few years (this last assertion might have been referring to changing the large industrial models to breakerless ignition, I think). I fully expected to see a Magnetron coil on the 92508 in the pictures - I've never needed to take the cowl off it before today. This diagram shows where the Magnetron module should be visible (the coil installs with it underneath, toward the engine, not on top, where it would be easy to see):

In the third picture in my previous post you would be able to see it up near the air vane, on the opposite side of the coil from the HT lead. And I agree, that was the object you circled in red on sparker's coil: it appears to be a standard Magnetron, just like in 1983. Maybe I should get my glasses replaced.

Well, Excluding a few from the late 90's and the last decade, I have (Going by by records it this point)

-1981 93508
-1980 92908
-1977 92502
-1989 100708
-1975 100902
-1985 92908

there is also one more, i havent noted its model yet, but i can remeber it, it's a 197s Rover Pedigree with the original 148cc Briggs on it.

I will look for the Minion when i get a chance, and as i go through restoring the above engines, i will document the restorations in a thread. (Looking forward to the 75' 100902, thats the Rover Super Four 21, From Redeye)

I know this is an old topic but I have a Pope mower with the minion plastic carb with 2 govenor springs.
Motor on this is a 098902-2030-B1
I have attached some pics on how the springs are meant to be connected.
Sparker's second spring seems to be connected incorrect and is overstreched causing the over revs.
Pics 1 & 2 are with govenor closed at 2 throttle positions.
Pics 3 & 4 are with govenor wide open using a screwdriver to actuate govenor arm.

Here is the B&S doctrine on how the single and double spring governors should look:



AS you can see, Fig 93 shows a dual-spring 98902 and Fig 96 shows a single-spring 98902. It seems both versions exist. In the older series such as 92908, only single-spring versions exist.

FWIW I only posted the reply in case someone wanted to hook the springs up properly, changing the control bracket isn't an option for most people.
I originally had a problem with the engine hunting at idle but couldn't find an answer anywhere on the net.
I finally figured that the idle spring needed a slight bit more tension and bent the tab to raise the idle speed and the problem went away.

I do believe that the 98892 after year 1996 have the 2 spring setup, B&S removed the manual idle screw on the throttle bellcrank and added in the idle govenor spring to increse the idle speed.
The only way to adjust the idle now is to bend the tab where the idle spring attaches too.

The way sparker installed the idle spring to the tab is incorrect as he has constant tension on the spring causing it to be on with almost full throttle irrespectively of the controller position.
The way it is meant to be installed is there is only slight tension when it is the idle position

Andy, B&S call the system that has the idle speed controlled by the governor instead of the idle stop screw, "governed idle". I agree that if you have a governed idle engine, you can't delete the feature without providing some form of idle stop on the carburetor, if it doesn't already have one.