timing and the flywheel.... learn me please... FIXED pg 3

[Mattyo]

FIXED!

Ok... so here's what I THINK it was.... I think I had the timing significantly advanced (not retarded). I took my dremel a cut a notch in the end of the crank to indicate roughly where the key was on the crank. I put the aftermarket flywheel back down with the romex as a key and aligned it as straight as possible. torque wrench down w/ blue loctite.... the saw RIPS now. all good.

thanks to all.

 

[nk14zp]

zippy is a clown name.

You rang?

 

[Terry Syd]

It's unmistakable, literally it pops in the cut

You mean as in 'misfiring'?

 

[jmssaws]

Advance it to far and it will pop as in fire on a open port basically, a 390 will do the same thing.

 

[Terry Syd]

it will pop as in fire on a open port

Now I'm even more unsure what 'popping' means. Are you saying it will backfire out the intake port?

 

[jmssaws]

I believe it's out the exhaust but not certain.
It's unmistakable and it's a loud popping .

 

[Mattyo]

well, my aim was for stock timing. I still didn't use a usual key, but I can say for sure now there is POWER and its not boggy.... all better.
and yes, I think there was some "popping" previously, just don't know any other way to describe it. probably means there is unburnt fuel because of the inefficiency in being so far advanced for timing

 

[jmssaws]

There really isn't a way to describe it but you will definitely know when it happens.

I never advance a 372 .

 

[Mattyo]

After this experience, i'm with ya. thanks for the help, even with the AM flywheel, the saw rocks now.

 

[jmssaws]

It's strange to me that the aftermarket one has a key slot in it and no factory way to make that work. Peculiar for sure
A 394 has a key and a 395 is made in it like a 372 and there the same flywheel but different cranks.

 

[Mattyo]

well, these flywheels didn't have a key with them, but they were part of a large parts lot that I bought... so I made a key out of romex.... all good but yes, I do like the 394 keyway setup

 

[Terry Syd]

yes, I think there was some "popping" previously, just don't know any other way to describe it. probably means there is unburnt fuel because of the inefficiency in being so far advanced for timing

OK, that describes a 'misfire' so I can understand how it could 'pop' in the muffler. I wonder if the misfire is more related to extra heat build up, perhaps in the plug. Does the popping occur only when the engine gets hot? Or does it do it all the time, even when you first start cutting?

 

[Mattyo]

noticed it even when first starting

 

[jmssaws]

I'm guessing you have a saw that's doing this?

 

[Mattyo]

had a saw..... its fine now, now that the timing is fixed

 

[jmssaws]

I was referring to the other gentleman

 

[Terry Syd]

Yeah, sometimes when my 77cc 365 gets good and hot during a long bucking cut (36"+ rounds) it can misfire in the cut. If I put the saw down to shift the round it cools and doesn't act up again until I get stuck back into another long cut. I'm thinking I should change the plug and see if that is it. Your comments about the 'popping' sound and advanced timing led me to heat build up as a potential problem.

I've blocked off the 'air injection' system (with a couple of holes in the back of the cover) so that all the air off the flywheel goes past the cylinder, so it is getting good air flow, but I am working the bugger pretty hard when it happens.

If this 'popping' sound occurs when the engine is still cool, then it is not the problem I have noticed.

 

[jmssaws]

Have you changed the coil?

 

[Terry Syd]

No, I'll try the plug first. It wasn't really a big issue until a couple of days ago when I was finishing up some long hard cuts and the saw really acted up as I finished the cuts.

 

[aokpops]

I use to do with mopeds . Not sure how to do this with key ways ?