Hi guys, new here. I'm not a mechanic by any means, but I received a 1980 model tiller from my in-laws and decided to try my hand at bringing it back to life. I was told that it ran, but smoked real bad when it was parked and replaced. It's been sitting for about 5 years. I watched a bunch of youtube vids to prepare for surgery but that's no substitute for experience so I've come for help.
What I've done: I tore it down, cleaned and repainted the case and sheet-metal. Cleaned all of the carbon from the piston, valves, and head which were otherwise in remarkably good condition. I put in a set of new rings, checked the gaps first and they looked fine. The cylinder wall was as smooth as a baby's butt which was a relief after seeing how much carbon was in the combustion chamber. I re-lapped the valves and put it all back together. Wouldn't start, so I thought the problem might have been the points, after a few hours of adjustments I could't produce a spark despite the very good appearance of the contacts so I replaced the whole deal with a Stenz Electronic Magneto and replaced the plug for good measure. Now is sparks good but it wouldn't start so I asked around and was told to check the valve clearance, I had neglected to do so because I was using the same parts and just assumed the clearance wouldn't have changed, but I was wrong. I had to grind the intake valve to produce a .006 clearance. The Exhaust was sitting at about .010. Put it back together again. It still wouldn't start. a few drops of gas in the spark plug hole caused it to backfire but not crank. I replaced the carb and tank (with fresh gas) and it still wouldn't run, so I figured it was a carb issue. I replaced the diaphragm, inspected, and reset the jet and screw (set to 1.5 turns out). Still nothing good. I've hit a wall. I borrowed a compression gauge and it's consistently pushing 60 lbs on first pull and hitting 70-75 by the third pull. The flywheel check also indicated sufficient compression. The timing marks are lined up for the cam and crank. The flywheel key has a small gouge in it (an accident during the repeated removal testing the points) but it's not sheered off.
Other Information that might be relevant. Fuel poured in the breather port of the carb sputters back out when the rope is pulled. not sure if back pressure from the intake is normal. Occasionally a puff of smoke will come out of the carb. Not sure if this is coming from the intake or if it's a puff of blow-by returning from the pcv line.
Can anyone think of something I'm missing? The engine does not look worn out, so I'd really like to get it running again. Not to mention it was manufactured the same month and year that I was born so I kinda feel a kinship with it, lol. giving up on it is like giving up on myself at this point and I'm too stubborn for that.
Something else I just thought of.
When I pulled the head back off to correct the valve clearance, I noticed oil around the top of the cylinder. I assumed that since it hasn't ran, it hasn't heated up and seated the rings yet, so I didn't think it was important. However, now I'm wondering if I'm losing compression through the rings. I didn't hone the cylinder because it was in great shape and I didn't think I'd get it any better than that with a hone. So, is honing actually just for smoothing out the cylinder? Or do the micro-abrations from the stone help the rings to seat?
Now I'm wondering if I should just start over. Did I screw up my new rings by dropping them into a cylinder that wasn't honed?
#3
Fish
You could just have it flooded badly.
#4
Scrubcadet10
I didn't hone the cylinder because it was in great shape and I didn't think I'd get it any better than that with a hone. So, is honing actually just for smoothing out the cylinder? Or do the micro-abrations from the stone help the rings to seat?
Only hone if you have a cast iron cylinder liner in it. You're aren't supposed to hone the aluminum or as briggs likes to call it "kool bore" engines.
And yes, the micro abrasions helps the rings bed into the cylinder. you'd want about a 45 degree crosshatch when honing/
Fuel, air, squeeze, spark at the right time, has to run. Clean the plug again and give it a good shot of starting fluid in the air intake at the carb and try it. I'd bet on something in the carb is not right.
Ok, found my original problem. When I installed the recoil clutch, I oiled the little sponge inside it, apparently I oiled it too much and it shot oil up the crankshaft and under the flywheel causing an instant shear after I had put in a good key. Resulting timing change stopped it from cranking.
Now that that's worked out, I'm having another problem.
It has a hard time starting without a primer of a few drops of gas in the carb. After it starts the throttle linkage on the carb fluctuates (everything is connected exactly like it was when I got it) and it eventually dies sometimes minutes, sometimes seconds. After cranking it a few times, and trying to adjust the idle screw it ran smoothly until I put it under load and it died again. Then, it had to be choked to crank but immediately died when choke was pushed back in. The governor is adjusted, I even tried reversing it to make sure I adjusted it correctly and when reversed it went wide open to the point its scared me as I turned to hit the kill wire.
The throttle linkage has a hole, about an inch from the governor spring that nothing is connected to. I've seen other motors online that have a rod in that hole with a spring at the top. Sometimes the rod goes to a bracket on the carb, other times the bracket hangs from a head bolt. I don't have either bracket so I'm not 100% sure anything goes there on this model. The throttle cable from the handle has no effect on the throttle unless it's pulled back far enough that the governor spring literally pushes on the bottom of the governor arm to raise it up. It has nearly an inch of play where it just slides back and forth for no reason.
Start the engine and move the governor by hand
You should be ablt to slowly open the throttle all the way wit the engine running strongly.
If it starts to miss the stops all together with no black smoke from the muffler then the main jet is clogged or the fuel pump is not working properly.
We really need a photo and the rest of the engine number
There are a few variations in the fuel system and it will get very confusing very quickly
The pump pulls fuel into the cup inside the tank
That cup replaces the float bowl on a normal carb.
If that cup has a hole in it or the fuel pump can not keep it full to overflowing the engine will run out of fuel when the throttle is wide open.
The bit of the carb that sits inside that bowl should have a fine wire cover and under that is the main jet, make sure they are clean.
The Type number is 0135-01.
The inner tank bowl was clean and full when I pulled the tank off. Both pickup screens are clean. It didn't seem to have a problem keeping fuel when it was running wide open but I didn't let it do that long for fear of exploding it. The problem seems to be fuel supply at low rpms maybe? I was reading about different things last night and came across tank vacuum due to clogged cap vent. I haven't had time to fool with it today but I plan to check that. Kinda makes sense as higher rpms would make more suction as would choking the carb and more suction would better combat a vacuum short term.
