I have been quietly working on the mower since I last wrote, I have changed the on/off switch back to the original one, no difference. still getting a pretty good spark. so i decided to have a look at the carb, but first i watched a heap of youtube videos explaining how to clean small engine carbs which was really helpful. so i took it off and pulled it to bits slowly remembering where i got the part from, firstly you can call me stupid but i cleaned it with petrol from the tank cause i had none in my petrol can. put it back together then thought i would clean out the tank also, well that was full of crud like blobs of black stuff(i suppose congealed petrol/oil mix)so i went to super cheap auto and got some carb cleaner (geez that stuff stinks)pulled the carb apart again and recleaned it making sure not to get any on the float as the manual says solvents will remove the varnish on the float and it wont work. put it back together. cleaned the tap on the tank and inside the tank got some new gas mixed in 2 stroke oil and it still wont start. I must say that the new petrol smells nice and fresh where the old petrol smelt bad probably stale. But now a whole lot of black oil is coming out from underneath the mower, i suspect the exhaust. why would it be doing that ? the youtube videos i watched showed what a healthy spark looks like and mine is the same. I'm now stuck again and need some of your good advice. any suggestions ? attached are 2 pictures of the cleaned carb it was pretty simple to do. like you said it's all about learning and i'm certainely doing that. Thanks Pete
P.S forgot to mention i squirted some new petrol in the plug hole and the air filter throat no difference
does the oil smell like fuel if so the needle in carby could be stuck open and letting fuel straight out of muffler
hey drjbeam,thanks for your reply
Yes it does smell like fuel, only thing is i put new petrol in and that's almost clear slight green tinge from oil, and whats coming out is black and thick. also any idea which needle it might be ? there are 3 one for engine revs one for air/fuel mix and one attached to the float which is on the other end of the fuel line from the tank. the bowl is filling fine. any ideas what i could try ?
Pete, if stuff drips out continuously when it stands there, without you trying to start it, the float bowl is flooding. That means the float needle, which is pushed up by the float, is not sealing in its seat in the top of the float bowl, right where the fuel hose connects. There is no other continuous source of fuel, it has to be coming from the tank by getting through the seat even though the float bowl is over-full. This can only happen if the float doesn't float, or the float arm pivot is distorted or stuck, or the needle is stuck, or there is grunge in between the needle and its seat, or the needle or seat is damaged. You need to check all of those things. Often you can do it easily by removing the float bowl top and assembling it with the float, float arm and needle, holding it upside down so the weight of the float is pressing the needle onto the seat, and sucking on the barb where the fuel hose connects. It must be air-tight; if it loses vacuum when you suck on it then seal the barb with your tongue, the needle is not closing the seat. Check all of the things I've just listed. Dirt is the most likely cause of leakage, but sometimes the cold enrichment device (that is pushed down by your kill switch) is just stuck down.
The black crud coming out of the bottom of the engine is probably coming from the side of the float bowl, then running down the dirty engine and base plate. However it could be coming from the bottom of the crankcase, along the crankshaft then across the blade plate. If it is doing that your crankcase seal is very, very badly destroyed (which does happen, especially if a bit of string or wire got wound around the crankshaft above the blade plate). Whatever the path the petrol takes after it leaves the carburetor, if it drips steadily, not just after you try to start it, you have a flooding carburetor and have to fix it.
Hey Grumpy, You and drjbeam are right the needle isn't sealing, air is moving in and out, no vacuum at all. so I'm going to have a fiddle with the float and attachments and see if i can get a vacuum. If not then i can take the carby off the other mower and check the seal on that, according to the manual the needle and seat are a matched pair.
also lifted the mower and looked where the black crud is coming from exactly. I dont think it is the crankcase seal as the shaft is clean.the crud is coming out of the exhaust hole, so it must be flooding and then running through the engine and out that hole. will keep you updated thanks Pete
I'm not entirely clear on what is happening yet Pete - without rotating the crankshaft, there doesn't seem to be a passage from the carburetor to the exhaust port that doesn't involve filling the whole crankcase with fuel. Anyway, step one is to get the needle closing off the seat.
OK Grumpy thats fixed now the float arm just needed a tweak with the needle nose pliers and the little clip was a bit crooked fixed that also and i've now got a really good vacuum nearlly can hold the carby off my tongue hahaha. So I'm back to square 1 cause it still wont start. no more black crud is coming out underneath so like you said thats a mystery at least the flooding is sorted, any more tricks up your sleeve as to why it wont fire up ? Thanks Pete
You have verified that it has good ignition, and you have cleaned out the fuel system including the carburetor. There has been a ridiculous amount of fuel in the crankcase and cylinder, and it won't start until they are removed. That is normally done by pulling the starter quite a few times with the fuel shut off, the spark plug removed, and the throttle open. When you are fairly confident you've dried out the engine interior (you'll probably be able to tell by the decreasing amount of petrol smell when you pull the starter rope), you should leave the fuel turned off and squirt some fuel either into the spark plug hole or into the throat of the carburetor. If it won't start as a dry engine with priming, the state of its compression will come into question. However I'm hopeful that you haven't yet dried out the flooding, and that's all that's wrong.
Hi Grumpy, Still no go, totally dried it out till there was nearly no smell. the primer is working cause i stuck a torch in the air filter intake and when primer is pushed fuel squirted(at least that works). I was reading a posting from mytractorforum . http://www.mytractorforum.com/showthread.php?t=133293 the guy had a 6277 lawn boy he put up pictures and the carby is exactly the same as mine(he mentioned the D series) he had similar problems as me but his knowledge is way more advanced than mine he striped it right down then rebuilt it.
I was thinking of cleaning the outside only of the other carby and trying it, what do you think on that ?
I have been under the flywheel again as the manual stated i had installed the flywheel slightly off as the yolk and weights are supposed to be picked up by a lug under the flywheel next to the key hole. do you know what the yolk and weights do ?
I Totally removed the kill switch from both ends, rechecked and re cleaned the points, as someone said don't let oil from your hands get on the points contacts. spark is a little bit lighter now don't know why. maybe the coil is slowly dying or the condenser is. the compression seams quite strong, i cant grab the shaft bolt with my hand and turn it with the plug in, its to strong. The Americans seem to have a readily available store for parts where we don't.
also was emailing a guy who worked on these mowers from 1968 on in NZ he said "The engine model number 4019 identifies it as a D4019 which was the second D series engine to come to NZ" so that proves that the engine wasn't made here.
Do you have readily available parts in OZ
Let me know your thoughts on the above stuff thanks Pete
Pete, don't be surprised that drying out the interior didn't make it go - it was one of the things that had to be done, but there may be several others. Did you squirt a bit of fuel into the plug-hole and try to start it? That isn't necessary if the primer is working, but let's not bet on that - it could be delivering a small amount of fuel and still look as if it works.
If the engine won't start with spark, a good (new) spark plug and priming, there are three main possible problems left: wrong ignition timing, an induction air leak (perhaps through the crankshaft seals), and a choked-up exhaust port or muffler.
When you said you have compression, you were talking about cylinder compression. A crankcase-induction two stroke won't start unless it has crankcase compression as well. If you can get access to the top and bottom crankshaft seals (where it goes through the crankcase) you can test them. Put each seal in turn on top, and trickle a little fuel onto the seal. If it vanishes into the crankcase, you have found a fatal fault (but not necessarily the only one). Remember, test both top and bottom seals.
The yoke and weights under the flywheel are the centrifugal spark advance mechanism - a rare and very useful feature of your engine. However it is a complication, and it is always possible that when you worked on it you somehow reassembled it with the ignition cam (which opens the points) in entirely the wrong place. That could even be why your flywheel won't go on properly, and why your engine won't start, too. It could even explain why your spark intensity varies, if the points are breaking when only the edge of the magnet is passing the coil.
Grumpy I've had yet another read of the manual just to check that I had installed the cam correctly it says Note: "In reassembly, make sure the smaller end of the flyweight is on the key-way side of the crankshaft" and I thought I didn't notice that NOTE last time so pulled it apart again and I had Installed CORRECTLY I was hoping it was wrong then I would have something to fix.
just to make sure top dead center is when the points are open at the fullest point when you rotate the crankshaft, is that correct ?
Ok I may have made a booboo when setting the points the manual says this. BREAKER POINT ADJUSTMENT NOTE To check or adjust point gap, place spark advance cam only. on crankshaft. Check and adjust points as described. (I had the key weight assembled when i set the points)
BREAKER POINT ADJUSTMENT D-400 SERIES To check point gap .020, rotate crankshaft until wear block is centered on lobe of cam. MOVE CRANKSHAFT TOWARD CARBURETOR AND HOLD IN THAT POSITION ( I don't understand the bit that is underlined) when I moved the cam so that the wear block was centered on the lobe of the cam, the hole for the key weight didn't line up with the hole on the cam so i rotated the shaft only until the hole lined up. Is that what i was supposed to do ? and then i should reassemble the key weight etc.
the yoke and weights have got a got detailed assembly in the manual except for one thing the 2 key weights have one thick arm and one thin arm. the thick arm sits on the outside of the governor collar but the thin arms sit on the inside. does this sound right because then the 2 thin arms would be touching the crankshaft.
I think that's enough for you to deal with for now. thanks again Pete
Edit I will have a look at the seals and check for leaks
just to make sure top dead center is when the points are open at the fullest point when you rotate the crankshaft, is that correct ?
No, the spark occurs when the points first separate from each other, and that has to be 6 degrees before top dead center. You set the maximum point gap with the cam at its highest point against the rubbing block, but that isn't where sparking occurs. Setting the gap and setting the timing are separate operations.
Originally Posted by Pcamore
Ok I may have made a booboo when setting the points the manual says this. BREAKER POINT ADJUSTMENT NOTE To check or adjust point gap, place spark advance cam only. on crankshaft. Check and adjust points as described. (I had the key weight assembled when i set the points)
I think they are just trying to make the adjustment process easier and more accurate. It shouldn't change the outcome if you do it carefully, but I recommend you do it their way, for practice.
Originally Posted by Pcamore
BREAKER POINT ADJUSTMENT D-400 SERIES To check point gap .020, rotate crankshaft until wear block is centered on lobe of cam. MOVE CRANKSHAFT TOWARD CARBURETOR AND HOLD IN THAT POSITION ( I don't understand the bit that is underlined)
There is always a bit of slack in the upper crankshaft bearing and between the ignition cam and the crankshaft, so you hold the cam and crankshaft pushed sideways, to give a consistent reading of the points gap.
Originally Posted by Pcamore
when I moved the cam so that the wear block was centered on the lobe of the cam, the hole for the key weight didn't line up with the hole on the cam so i rotated the shaft only until the hole lined up. Is that what i was supposed to do ? and then i should reassemble the key weight etc.
As I read it Pete, on Page 6.3 it says you adjust the points by just putting the ignition cam onto the crankshaft and rotating it until the points are at their widest gap. Then on Page 6.4 it describes a different way to adjust the points, with the whole spark advance mechanism assembled. I think either way will work - it seems you use the 6.3 method if you've taken the centrifugal advance apart, and the other method if you are just doing a routine service and don't want to take everything apart.
Originally Posted by Pcamore
the yoke and weights have got a got detailed assembly in the manual except for one thing the 2 key weights have one thick arm and one thin arm. the thick arm sits on the outside of the governor collar but the thin arms sit on the inside. does this sound right because then the 2 thin arms would be touching the crankshaft.
You can probably verify the correct assembly by checking the ignition timing: with the weight pushed in close to the crankshaft, the points should just move at 6 degrees before top dead center. With the weight pulled away from the crankshaft, the points should start to move at 26 degrees before top dead center. Most likely if you put it together wrongly you won't get the correct amount of movement. Also, look at the slot in the ignition cam where the anchor screw sits in the hole in the crankshaft. It would be most of the way in one direction with the weight inward, and most of the way in the other direction with the weight outward.
Originally Posted by Pcamore
I think that's enough for you to deal with for now. thanks again Pete
Edit I will have a look at the seals and check for leaks
I hope you can figure out who said what above, Pete. You can check the ignition timing in several ways, but the two you can use when the engine isn't running are either look closely at the points as you move the crankshaft forward (clockwise), or hold onto the high tension wire while you move the crankshaft forward. The Mark I Eyeball method is more accurate, if your eyeballs are in good working order and it is easy to see the points. I recall using the HT lead method on an old Villiers once because the points were hard to see.
GRUMPY !! I got 1 kick over and that was it YAY i'm getting somewhere. It helps when you put on your reading glasses which i have been doing to set all gaps, but they happened to still be on when i noticed that the yoke had a tiny word written on it "KEY" I also put the kill wire back on but put insulation tape over the ends only. Not where the screws are just where the wire goes into the eyelet shaft. also took off the coil again and gently pulled the wire through the bit in the head that it goes through and found a suspect piece so wrapped tape on that also. oh and by the way there is a proper and very easy way to put the pin and spring back into the fly weight(sorry i've been calling it the key weight)it goes in over the top not underneath like a dream. the top seal by the armiture is good trickled some petrol onto it and it just sat there not moving had to dry it out with a paper towel. the other one is a bit more tricky. also was contemplating taking off the exhaust and checking for carbon build up, but the nuts are seized so i sprayed CRC on them a bit worried if i snap them. how is the other end attached ? and if they can be replaced.
Sounds promising, Pete. If the top seal is good, and it starts and runs, the bottom seal isn't a priority. Worry about it if you have problems tuning it later.
Normally the exhaust is held on by studs screwed into the cylinder. If the nuts resist unscrewing from the stud, usually the stud screws itself out of the cylinder. No harm is done if that happens, but it is a hassle then to get the nut off the stud. Best to get the nut loose from the stud in the first place. Also, particularly if there is corrosion on the cylinder, sometimes the stud is frozen into the cylinder, and breaks if you try too hard to screw it out. Do not break a stud off - it is a pain to get the broken part out, and often leaves you with a damaged cylinder. Nevertheless, you should remove the exhaust and clean the port - it is a regular service operation described in the manual. Be sure and follow the directions in the manual: use a piece of wood, not metal, for the job.
So, are you getting a reliable, strong spark? Seems like you've had plenty of problems with that kill wire. And, if it started easily and ran well, it sounds as if you have the right ignition timing and are managing to put the flywheel on properly.
Grumpy sorry mate you misunderstood me when i said 1 kick over i meant 1 chug or cough or whatever you call it.
Yes the spark is really strong now and consistent.
OK I just went and tried it again and this time it started and ran for 20 seconds,really roughly chugging and coughing white smoke before stopping. how do i tune the mixture ? The manual only mentions the air/fuel mix knob turning until in its seat then backing off 2 turns
You have cleaned the fuel tank and the carburetor, and you have the float chamber working properly. Did you clean out the fuel line from the tank to the carburetor? That will have been full of crud too.
The white smoke may have been unburned fuel, due to prior attempts to start it. You also have a lot of fuel in the muffler, left over from the flooding situation. If that is the story, a few more attempts at starting might lead to it gradually clearing its throat and running better/longer. If that doesn't happen, cleaning the muffler and exhaust port may help. If neither of those helps, you should still check that ignition timing: where is the flywheel, compared with top dead center, when it fires?
I think you are getting closer to success Pete, but you need to get it running steadily to be able to tune it. Meanwhile just use the manufacturer's starting point for mixture adjustment. We don't know whether there are any assembly problems in the carburetor, so the first focus is to see if it will run continuously so you can experiment with the mixture. If you can get to where it is running and you are turning the mixture control looking for the sweet spot, you are on the verge of success.
To check the timing without taking the flywheel off, mark TDC on the flywheel with a pencil, and make a corresponding stationary mark on the crankcase or whatever is convenient. Back the timing mark up anticlockwise a couple of inches, grab hold of the live end of the spark plug lead with one hand, and move the flywheel clockwise with the other hand, until you feel an electric shock from the plug lead. (Turn it slowly, and speed up a bit if you can't feel it). Make a second mark on the flywheel at the firing point. The firing point had better be to the right of the TDC mark (engine runs clockwise, and it has to fire before it gets to TDC). Measure the distance from the firing mark to the TDC mark, and measure the circumference of the flywheel. Divide the firing mark to TDC mark distance by the circumference, and multiply the result by 360 degrees. That tells you how far before top dead center it fires. It should be 6 degrees. It increases to 26 degrees when the engine is running. Be very sure it is firing before TDC, not after TDC.
If it consistently starts and stops after 15-20 seconds, you have a fuel feed problem. You haven't left the fuel tap in the off position have you? If the tap leaks a bit, that could be the problem. Or the tap could be restricted. Or the float needle could be stuck close to the closed position. 15 to 20 seconds is probably about the time it takes to empty the float bowl.
Hi Grumpy Mate I didnt take physics at school or algebra. that method for checking timing is beyond me, even my 20 year old daughter who went right through high school to year 13(7th form) couldn't work it out. sorry mate we must be dumb. is there any other way to check it ?
Yes the tap on the tank is leaking a little i might swap it with the other one. it wasn't leaking before i pulled it apart. the gasket or washer made out of some sort of material was falling apart i left as much as i could alone but obviously not enough. Is there a way to make the gasket inside the tap ? I doubt i will be able to get one anymore. Pete
I'll start with the fuel tap: the problem I was talking about would only apply if you were trying to run the engine with the fuel turned off. That isn't going to work, whether the tap leaks or not. Have you checked which position is on and which is off, by disconnecting the fuel hose at the carburetor end, putting the end of the hose in an empty tin, and seeing how fast the fuel flows into the tin? My concern is that you have mistaken the off position for the on position, or the tap is blocked in some way. You need to see fuel running into the tin at a decent rate.
If the fuel tap gasket is conventional (a sort of cardboard-like material, but tougher and fuel-proof) you can buy a piece of it from an auto shop. To cut the internal hole, though, you will need a wad punch of the correct size. You can use snips or scissors to cut around the outside.
I'll give more detail on the ignition timing. First, measure the diameter of the flywheel, and tell me what it is. I'll tell you how far ahead of top dead center, measured in inches or millimetres on the outside of the flywheel, to draw the firing mark. All you need to do is find TDC accurately by putting a pencil through the spark plug hole and turning the flywheel until the pencil has been pushed out through the plug hole as far as possible by the piston (that is TDC). Now leave the flywheel exactly in that position, and make a convenient mark anywhere on the crankcase directly below the outside of the flywheel. Use a square to make a mark directly above it on the outside of the flywheel. When you've done that you can easily find TDC any time you want, just by turning the flywheel until the flywheel mark is directly above the mark on the crankcase. If you do that and tell me the flywheel's outside diameter, I'll explain how to make a firing-point mark.
Hi Grumpy, OK the fuel tap has a wind in wind out type tap. screwed clockwise the tap is closed anticlockwise its open. I have had the mower for years and used it for years so i haven't mistaken which is on and off. I will check the fuel flow tomorrow it's after 10.30pm here in NZ
The Diameter across the top of the flywheel is 16cm or 160mm the circumference is 160mm x 3.14(pi) = 502.4mm (had to look that up on the net)
