Nik's Poulan Thread
- Thread starter FATGUY
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I didn't get to the 5 saws today afterall. Got sidetracked. Maybe this weekend..
Try putting the flywheel back to stock and see if you get the same noise. It could be the clutch or something else.
I found a pyramid with all the reeds on ebay for the Homelite 901. It runs great now. I also made a new gasket for the carb fit to the reed block.
Are they all Poulans.
Thanks Roger. I'll give it a try today. It starts hard as well. All else is working well on it.
I put the key in reversed to get it back to stock. I mic'd the key today and it was actually .017" off the key. Sounds good now and starts easy. I think I will try .010".
The saw seemed much snapper with advance on it.
Sounds like you had quite a bit of advance. And yes with all that advance they do seem to be snappier and can sometimes kick back on ya.
I would go for the .010" and see how that is. Most of the benefit of advancing will actually be at the high RPM's.
Any idea where to start degree wise?
I assume the saw is set at around 25 deg of advance by design. I don't have a degree wheel or piston stop to check. By calculation each .0022" of key reduction is 1 deg of ignition advance.
It looks like I had it bumped 10 deg. to start with. The .010" should about 4.5 deg advance.
That's a nasty temp drop.
I would not go more than 4 degrees advance. That is a pretty good amount. So if .010 is 4.5 degrees than try that.
I haven't filed a key down. Mostly on the retrofit coils it has been the timing light, degree wheel and piston stop. I don't know what the factory advance is on the Poulan's. I have set Homelites and Pioneers at 28-32 and it starts getting rough beyond that.
Just for kicks, I reverse calculated using 0.0022"/degree, at point where one assumes the key inserts into the plane of the crank surface. Given that, the arc length of the radius of the shaft plus amount of key protruding there would be 0.792" through 360 degrees. That produces a circle with diameter of only a 1/4". It gets tricky once the key is filed and the flywheel turned. Instead of the key bearing evenly against the flywheel keyway, only the outermost (radius) edge does. It has been asymmetrically offset. The diameter would be measured there for advance/retard. If the key were removed and the the 0.0022" of arc length per degree were measured off of the crank radius, the diameter of the narrowest point of the tapered shaft becomes 1/4".
Cool problem has me thinking. Always curious how others calculate/analyze problems.
There's a couple of tanks on fleabay now...probably will go away quickly.
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Actually none are. Big old ugly antiques. I might have intersted in one or two but always good to have trading material for later down the road.
Might try to make it over that way later this weekend.
I think you over thought the process. The shaft diameter is 0.625" The taper on the shaft shouldn't mater as the taper in the flywheel is the same. The shaft will turn at the same rate no matter where the key is located on the shaft or taper. Ultimately you talking a shaft dia of 0.625". If you use that diameter to calculate the degrees of rotation you would divide the circumference of the shaft by 360 degrees. Each degree in that case would be 0.00545" (CORRECTED from 0.0022"). It becomes a larger number if the crankshaft is a larger diameter.
I don't compensate for the sloppy needle bearings.
Make sense?
While I was typing this I forgot about my hotdogs on the stove. They done got blowed up.
Dang another 60cc project to add to the rest of the projects 
. Going to take awhile to dig myself out of this pile 
.
Found 2 380 and closed deal on 1 so far.
. Going to take awhile to dig myself out of this pile . Found 2 380 and closed deal on 1 so far.
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