Stihl 044 rebuild problems

[bretts]

I rebuilt it with a AM BB 046 cylinder, ported it and checked squish. The squish checked out at .025". The saw is an early Stihl 044 with the 10mm piston pin, I built the saw with a 046 12mm crankshaft. I did this to enable me to put the big bore kit on it. I also built it with new OEM bearings and AM seals.
Went to try to start it and could only get one revolution out of it per pull, seems like excessive compression (checked it cold at 210psi). I managed to get more revs when pulling on the starter cord and the handle snapped out of my hand and back into the housing, tried again and the same thing happened but got wisps of smoke out of the exhaust. I tried again to pull it over but this time the starter cord stayed out, Took the cover off and the starter spring jumped out at me followed by broken pawls and spring clip.
Before I fitted the 046 crank I measured and checked the stock 10mm crank against the 046 crank which measured the same as the 044 crank but with the 12mm pin and slightly heavier, what I didn't look at was where the flywheel key sat on both the 044 and 046 cranks.
The f/wheel key on the 046 crank is advanced one full key width ahead of the 044 key, what I did was remove the key and refit the flywheel with it's slot facing where the 044 slot on the crank would be.

Worked out it had excess timing advance by the way the handle snapped out of my hand because of the difference in the 044 vs 046 key ways but soon had the crank key and flywheel issue sorted.
Managed to start it and it run well at my home, I had it in some wood to test it and took it to my fathers place so we could collect firewood for him, it was there that it failed..., I ended up using a Husqvarna 51 and a Chinese chainsaw that I built for him. I couldn't tune the Stihl, it wouldn't idle very well and would idle too high or too low and I had the idle speed screw turned all the way in, in the normal position it would die, at random times it would rev like mad at idle and sounded very lean. The high speed was fine interestingly with plenty of power but boy would it drink the fuel,, I pulled it down and checked for leaks and because I don't have a vacuum tool so I poured petrol into the carb and turned the saw on its side to see if the seals were good, I found the clutch side was fine but the flywheel side was bad, so bad that the petrol poured out.

I am now stuck with do I fit OEM seals or continue with AM?. OEM are prohibitively expensive here in New Zealand imo.

 

[Basher]

Did you loose the garter spring during the install? All of the AM seals I have installed so far are still on running saws, no problem with them to date. If the spring dislodged during install then that might account for it leaking so soon.

 

[junkman]

I was not aware a wider 046 crank would fit a narrow 044 case ,and normally the 12mm crank will not spin in a 10mm case ,the weights normally drag the bottom of the case .

 

[huskihl]

I was not aware a wider 046 crank would fit a narrow 044 case ,and normally the 12mm crank will not spin in a 10mm case ,the weights normally drag the bottom of the case .

Or in my case, with a really early 044, 4mm recoil bolts, the big end of the rod hit, but not the counterweights.

 

[bretts]

Did you loose the garter spring during the install? All of the AM seals I have installed so far are still on running saws, no problem with them to date. If the spring dislodged during install then that might account for it leaking so soon.

Pretty sure I didn't loose that spring, in order to see if I did I would have to nearly destroy the seal to see.

 

[bretts]

I was not aware a wider 046 crank would fit a narrow 044 case ,and normally the 12mm crank will not spin in a 10mm case ,the weights normally drag the bottom of the case .

This saw is an experimental saw, I wanted to see if the crank would fit and if the 54mm 046 big bore kit is as bad as I read.
I can say (when the saw was running) that I didn't have to rev it as hard and it seemed to chomp through the wood quite well. With that being said I am sorely tempted to fit a 52mm 046 c/p, reason being I don't want it to over power my standard (for now) 064.

 

[Adirondackstihl]

I was not aware a wider 046 crank would fit a narrow 044 case ,and normally the 12mm crank will not spin in a 10mm case ,the weights normally drag the bottom of the case .

This ^