Poulan P3416, won't start and carburetor rebuild

Hi, my 3416 Poulan chainsaw would stall at full throttle and idling, so I changed the carburetor kit (gaskets, screen, needle & inlet lever). Now it won't even start! If I take the carburetor apart, I can see gas in all the cavities so I know gas is flowing through it. L / H jet holes are also clean and adjusted to 1 1/2 turn each (from fully closed). Spark is blueish so it does fire fine. Compression also seems good. Putting a small amount of gas directly into the cylinder doesn't start it. What else could it be?!? I'm all out of idea :-(

Thanks!

 

How much compression does it have? You might want to borrow/rent a gauge and see.

 

Hi, sorry for the long delay. I couldn't find my compression tester and instead of fiddling with my Poulan P3416, I've decided to buy a P4218 instead. But after some garage clean up, I found my tester lol. So I checked the compression and I get 30 PSI after a pull and goes up to 100 PSI after three pulls.

It can hear it firing once or twice every other pull, but not enough to keep it going :-(

Oh yeah, I did ended up replacing the whole carburetor and primer bulb before buying the P4218 but that didn't change anything.

 

If you have spark and over #100 lbs of compression and no start with sporadic firing you have a flooded engine.

 

Cold engine. Fresh fuel, fresh plug, sat since yesterday. Push the primer six times, full choke, pull slowly until it fires (hard to tell that it fires though, weak), set choke to half throttle and pull until it starts. Doesn't start.

 

You don't pull slowly, you pull like you mean it. If the engine is flooded, applying choke is only making it flood more. Don't prime it, don't choke it at all, not even half choke. Give it full throttle with the trigger and pull the rope sharply several times and see what it does.

 

Actually, what I described is how you should start a COLD Poulan chainsaw, according to Poulan. I did manage to start it but it only runs for about 10 seconds before it stalls, and it's at half choke. It stalls right away if I unchoke it.

 

So the problem is hard starting, but it dies right away without the choke and after ten seconds or so with half choke?

That pretty well describes a bad pump diaphragm in the carburetor. Try starting it and see if the primer will keep it running. The primer will substitute for the pump in the carburetor to fill the fuel reservoir in the carb.

 

Yep, sounds like the carb needs cleaning at least. I can't recall ever seeing any manufacturer recommend pulling the pull rope slowly.

 

I'll try priming as it runs and see what happens, although the carb was changed. It's brand new. It behaves the same way with the carb rebuild I did.

The saw is at the cottage so I'll try it next time I'm there.

Thanks.

 

Try it with the primer bulb. With a new carb the pump diaphragm shouldn't be the problem, but the pumping circuit may well be. That would be lines/line connections/about anything that could let an air leak work against the pump.

Also, there is a pulse port coming out of the crankcase that has to be clear. Sometimes a carb gasket gets put in wrong and covers the port.

Then you have about the same thing with no pump to fill the carb. Following starting instructions on that saw you'll push the primer a few times and that will push fuel through the carb and fill the reservoir. Then you start it and the fuel put there by the primer gets used up and without a working pump the engine dies.

Let us know if the primer keeps going and check the pulse port coming from the crankcase. That'll give us a good start on a fix.

 

Will do. Thanks for the help.

Btw, I didn't know what a pulse port was and when looking for it on the Internet, I've found this great tech guide that explains how the Zama carb in my Poulan chainsaw works: http://www.zamacarb.com/pdfs/TechGuide_2007.pdf

Also found that one for a Walbro carburator: http://www.walbro.com/media/21936/SERVICEMANUAL.pdf

 

Got it running

Turns out the gasket between the carburetor and the engine wore down (took it off too many times I guess) around the screws that holds the carburetor in place and therefore the whole in the gasket wasn't aligned with the hole on the engine. Since I don't have spare gasket (yet), I've aligned it carefully before putting the carburetor on.

While I was at it, I've also used my 0.2 mm feeler gauge to adjust the gap between the fly wheel and ignition coil and cleaned the air filter.

Would still stall at idle and would still bog down at full throttle but by adjusting the L/H mixture screws, got them set right and now it's working almost like a new one

Thanks for your help.

 

Well..it seems to me that..no start up with gas in the chamber I would say..check the flywheel key..some are made on the flywheel some aren't..if that's good..then u may not wanna stress..keep it for parts or throw it away..