PoulanPro 330 revs high and quits

[zart1953]

I bought a PoulanPro 330 on eBay and the saw never ran as well as I thought it should. I bought a new piston ring, gaskets and carb boot (the original boot was torn). When I pulled the jug off, I saw a brown stripe on the cylinder wall about 1/4 inch wide. When I put the new ring on, I noticed the old one had a larger gap in it. I am assuming it came this way from the factory based on the brown stripe in the cylinder. The cylinder walls looked good and a bit of emory cloth removed the brown stain. I could still see the original hone marks.

OK, so I put it all back together and I start the saw and it revs high and quits. I removed the carb and checked the carb boot and everything is good. The compression seems a bit soft, so could I have a leak on the crank seal, or the jug seal? Any thoughts? I was careful when I put it back together.

 

[1wildthing]

Sounds like an air leak somewhere. Check head gasket, crank seals, etc.

 

[HiOctane]

Wildthing is right,looks like air leak.Check cyl gasket condition and other gaskets .I dont know this particular model,but if you have a separate pulse line,check if well connected or cut.Are you sure intake gasket is well positionned ?

 

[Hard Knocks]

You may have an air leak at the seals or base gasket but that should not affect compression. Have you done a compression test? Did you check the impulse line to make sure that it is hooked up?

 

[zart1953]

PoulanPro 330

Thanks for the quick response. I replaced the jug gasket, carb boot, carb gaskets and exhaust gasket as well as a new piston ring. I reconnected the impulse hose, but didn't check it for damage. I have not performed a compression check and will have to go buy a compression gauge to do that. If the piston doesn't have any pitting, or damage to the top, is there any reason to replace it? One other thought is could I have damaged the jug interface when I scraped the old gasket off?

By the time I am done, I will be pretty good at tearing this unit down and putting it back together.

 

[HiOctane]

Thanks for the quick response. I replaced the jug gasket, carb boot, carb gaskets and exhaust gasket as well as a new piston ring. I reconnected the impulse hose, but didn't check it for damage. I have not performed a compression check and will have to go buy a compression gauge to do that. If the piston doesn't have any pitting, or damage to the top, is there any reason to replace it? One other thought is could I have damaged the jug interface when I scraped the old gasket off?

By the time I am done, I will be pretty good at tearing this unit down and putting it back together.

The compression is not related to the problem you describe(high rpm).Dont replace the piston if not scored or seized,but the ring should be replaced if you got more than .025 of gap.I dont think you damage the interface.Does the seals are well positionned,could be also a seal lip in "reveresed postion"
if you played with them.If the crank bearing have pin locator,check if they are at the right place because you could get an air leak between the two faces of crankcase.

 

[Hard Knocks]

The piston should be free of marks all around the sides as well as the top. If you do not see any wear around the skirt or the top than it should not be a problem to return it to service. The fact is that it did run on that piston before you replaced the ring. If you used a razor blade or good gasket scraper on the base and did not burr the surface than you should not have any sealing issues.

Is your gas fresh? Does the saw rev up and die every time you try to start it or was that a one time thing. When a saw revs up high and quits it is usually because it is not getting a steady supply of fuel. It revs up as it is leaning out. Have you cleaned the carburetor?

 

[zart1953]

PoulanPro 330

Thanks for the fresh and low fuel idea. I will try that tonight. This is a great forum, near instantaneous inputs from a world of experts! Happy Thanksgiving.

 

[Dadatwins]

You might have a bad crank seal, quick and easy test is spraying some carb cleaner around the seals when the saw is running, any change in pitch will show an air leak. Good luck.

 

[zart1953]

PoulanPro 330

I just wanted to throw out a dumb question. After reading a number of reviews and seeing some of the pictures of scored pistons and cylinders, my components don't look so bad. Other than the piston, ring, cylinder and spark plug, are there any other sources for loss of compression? I plan to pull the jug and measure the piston and bore this weekend in my spare time.

 

[zart1953]

PoulanPro 330 Help!

My saga continues. I rebuilt my PoulanPro 330 and now it has great compression. The problem is that when I put it back together and start it, it only will run on partial choke, implying a leak somewhere in the intake. The intake boot is new and not cut, the carb gaskets appear to be OK, so where do I look?

The one thing that is bothering me is that there is no gasket between the carb and the plastic handle interface prior to the intake boot. I tried to place an "o" ring in between, but it didn't resolve the problem. Also, the flange on the back-side of the intake boot is a soft metal and distorts when I tighten the two carb nuts. I removed it and flattened it and reinstalled it with no improvement. This one is frustrating because I think I fixed the hard problem when I replaced the ring and cylinder! Thank goodness I have my good old vintage Roper 3.7 woodchucker. Any ideas?

Art:greenchainsaw:

 

[Cut4fun]

Just tossing out ideas.
Did you rebuild carb, diaphragm dried up?
Did you check and replace impulse line, fuel line too maybe, did you check fuel filter and replace, tank vents checked. Crank seals, base gasket leak?
Hopefully someone with real ideas to get to the bottom of it will chime in for you.

 

[Cut4fun]

Look at part #13, carb gasket, etc.

Poulan 330 IPL http://www.odref.com/poulan/pdf/POULAN-PRO/gas-saws/pp330.pdf