Frustrations Rebuilding a 440

[Ax-man]

Lite, that pulling the T handle out of your hand on the second or third pull is not all that unusual. I don't know if that 44 has a decomp valve or not,some do some don't. What is going on is your compression is building up along fuel in a cold cylinder but you don't have quite enough compression built up for the saw to fire.

Sometimes you just have to put the saw down on the ground with your foot in the handle , grit your teeth and give that starter cord an authoratative pull on the rope. In other words your pulling too slow. To me the present day Sthils need a faster pull to get them to fire than the later generation of Sthil saws did.

I know it can be a pain in rear when a saw does this. If you can find BDC instead of just before TDC then give it a good hard pull it is easier on the hands.

I just rebuilt a 56 mag 2 from the bottom up and that darn thing has no decomp valve. That darn thing will pull the rope right out of your hand on a cold start if your not careful. My poor old shoulder doesn't appreciate it but it is worth the aggrevation once I get it running.

Larry

 

[litefoot]

Ax,
You may well be right, but I've got quite a few hours behind a 460 and a 7900 and this type of thing was a rare. Maybe I was lucky. But to have the 440 do this consistently is a bit worrisome...especially when I know the compression is lower than it should be.

 

[litefoot]

I too would say run it more before taking a final compression reading.As far as the module/ignition problem,was the flywheel key replaced or the old one used?I've experienced problems with keys in the past and learned to replace them with a new one.Same to the compression release,new or old,these go bad in time.I once had a 394 Husky that took a load from flywheel to clutch(a large white-oak) and it displayed similar symptoms before the connecting rod bearing went and the piston turned in the cylinder.

Thanks for the suggestions, jw. Yeah, I thought about the compression release too, but it did pass a pressure/vac test. But as I write this, I'm thinking that the operating pressures in the upper cylinder are much higher than the test pressures in a pressure/vac test. Hmmm....

FW key is the old one.

 

[litefoot]

Hard to say without seeing and feeling them in person. If your finger nail catches the scratch, it's usually too deep. You might just have to run it for a few tanks and check again. 10-12 tanks should have the rings broke in good. That's a bunch of sawing. Sounds like you are sure that there is no more foregin material left. I have a spare oem 440 jug you could borrow to rule out a bad "ring to cylinder wall" seal. From all you have gathered and what I read, put some more tanks through it....

Thanks for the offer, 2K. You're a standup guy. I'd probably just ruin your cylinder too.:hmm3grin2orange: I'm probably going to sand those scratches with some fine sand paper and run the sucker. Hopefully things will clean up. I just don't think there will too much compression increase during break-in. Those bearing cages did more damage than I thought.

 

[litefoot]

I got on the cylinder with a Scotch-brite and WD40. Put it all back together and gained abut 10 psi (over 150 psi now). So I'm done. I'm gonna run it as it is, put some mileage on it and check it out again after some run in (as was suggested here). Thanks everyone. I repped who I could, but some of you will have to wait until I get reloaded.