066 trying to break my arm

[Lumptastic]

So I’ve got an older 066 no decomp. I’ve had it happen in the past here and there. Go to start it and right about TDC the pull cord stops dead and it feels like it firing early. Kills your hand and after a few times you just have to stop. Anyway here recently that’s all it will do. I’m pretty certain it’s a firing issue doesn’t do it if I unhook the plug wire. Already pulled the flywheel and it didn’t sheer the key so what other causes could there be for early firing?

 

[Maintenance supervisor]

A little fuel seepage into the cylinder could be vapor locking it? Does the carb need rebuilt?

 

[Lumptastic]

I don’t think so. It hasn’t been rebuilt in a while. If I was to get that to happen multiple times within a few min then pull the wire off the top of the plug and pull again it shouldn’t change correct? I haven’t done it in that order I just put the flywheel back on earlier. I have it a few pulls with the plug in but wire unhooked and it turns over just fine wire back on and it’s doing it again. All the parts are correct for the saw I’ve had it three years and put a lot of time it with it running perfectly fine. There was the odd time it would do it once or twice but then always fired up and ran great.

 

[L34]

Just be careful removing the plug lead.
Trying to fire with nowhere to go can damage the coil.
I always run a lead from the plug boot spring to the cylinder if doing this if the switch is to be in the "on" position.

 

[Maintenance supervisor]

Retard function in the coil has failed.

 

[Lumptastic]

Just be careful removing the plug lead.
Trying to fire with nowhere to go can damage the coil.
I always run a lead from the plug boot spring to the cylinder if doing this if the switch is to be in the "on" position.

Didn’t think about that but it makes sense. I guess next time I do anything like that I’ll just hook a jumper wire from the boot to one
Of the fins on the cylinder. Sounds like the coil is shot anyway I kind of suspected that.

 

[Lumptastic]

Retard function in the coil has failed.

Kind of what I had expected but wanted confirmation from someone who might actually know what the hell their talking about.
Thanks

 

[Maintenance supervisor]

Well I wouldn't say that I'm an authority on the subject, lol.
I think you've eliminated most o the possibilities and that really narrows it down to the coil malfunctioning. Your the one who did the hard work.

 

[67L36Driver]

Retard function in the coil has failed.

And, the aftermarket coils from China don’t employ that function.

Ask me how I know. [emoji2959]

 

[Vintage Engine Repairs]

If you want to know timing for certain, you need a degree wheel and a timing light. You may find the timing is actually not the issue.

 

[TRTermite]

If you want to know timing for certain, you need a degree wheel and a timing light. You may find the timing is actually not the issue.

I will be watching this thread. MEBBE i will learn someeytnin'. I already learnt That i will be searching this site for information on the Degree wheel and timing light.

 

[Vintage Engine Repairs]

I will be watching this thread. MEBBE i will learn someeytnin'. I already learnt That i will be searching this site for information on the Degree wheel and timing light.

It’s fairly simple, set up a degree wheel and put a mark on the flywheel and on the case at TDC.

take that degree wheel off, run the engine with a timing light hooked up and note where it’s lighting up, turn the engine off and mark the case where it lights up. Engine back on and recheck your points align, if not re draw your mark. Note that You’ll need the recoil cover held on by one bolt that you can then remove while the engine is running - careful of fingers!

re attach the degree wheel and zero it again using the two marks from earlier, then align the flywheel marking with the second case mark by rotating the crank check what the degree is and that’s how you time it. I’d expect your timing to be around 26-28 BTDC

might be a good video to add to my channel. We’ll see.

 

[TRTermite]

Would it be possible to drive the crank from the flywheel side with a drill (Spark Plug removed). Seems if the saw is hard to start or won't start you could get a "jump Start" on trouble shooting the issue. Is thedegree wheel is attached on PTO side?

 

[Gord404]

Starting a rebuid 660 last week and was kicking back without the decomp on, pulled the carb and pressure tested it and it wasn't holding and of course it was sending gas down into the pulse line and into the crankcase causing problems, hopefuly I fixed the kickback problem if it does it anymore I will change the coil, been sitting for a couple of days and will try it today to see if it is still behaving.

 

[TRTermite]

Starting a rebuid 660 last week and was kicking back without the decomp on, pulled the carb and pressure tested it and it wasn't holding and of course it was sending gas down into the pulse line and into the crankcase causing problems, hopefuly I fixed the kickback problem if it does it anymore I will change the coil, been sitting for a couple of days and will try it today to see if it is still behaving.

Always more than one possible diagnosis. Keeps my Lurking interesting.

 

[Gord404]

Well it fired up with no problems and did it a couple of times, seems to have lost it's out to get me thing by rebuilding the carb and checking to make sure it held under pressure, about 15 lbs positve on gas inlet.

 

[pioneerguy600]

I have an early model 066 that no one will start or run it, it has broken 3 new ElastoStart handles and line, given me bloodied back of hand and knuckles but when that saw is running it throws chips 30' off its .404 chain. It is the coil on mine, it`s lost its retard for start function. I played with retarding the flywheel about 6 -7 degrees and it will start without kicking back but loses on top end torque. I could swap out the coil as I have a few spares but it would allow others to grab and use it if they knew it wouldn`t bite them. It`s an early no decomp cylinder with .015 shaved off the base.

 

[Gord404]

I have an early model 066 that no one will start or run it, it has broken 3 new ElastoStart handles and line, given me bloodied back of hand and knuckles but when that saw is running it throws chips 30' off its .404 chain. It is the coil on mine, it`s lost its retard for start function. I played with retarding the flywheel about 6 -7 degrees and it will start without kicking back but loses on top end torque. I could swap out the coil as I have a few spares but it would allow others to grab and use it if they knew it wouldn`t bite them. It`s an early no decomp cylinder with .015 shaved off the base.

Ya had an 084 like that, decomp was crummy and really did a number on my hand, did the carb as well as put a coil and 2 slot setup off another one I had, worked good after that but got the owner to bring me an elastostart as well before he put it to work.

 

[buzz sawyer]

My Homie 1050 was like that - I put a snowmobile starter handle on it so now I can pull with four fingers. Did the same with my SP125C and it has decomp.

 

[a. palmer jr.]

I had an 044 like that. I solved my problem by trading it to a neighbor..