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Poulan Chainsaw Won't Start

Posted by JPSwede none (My Page) on
Sun, Jun 8, 14 at 0:01

I have a 2 year old Poulan 4620AVX chainsaw that slowly died while I was cutting a tree down so I thought it had run out of gas. Unfortunately not. That was a week ago and I have yet to get it to even "turn over" once, aka "pop".

When I pull on the starter rope, there is no backlash if you know what I mean. It just spins. There is resistance, just no solid resistance like it's ever going to "kick" in. Again, the resistance just feels the same from the beginning of the pull to the end.

It is getting spark and gas so does the problem sound like a timing issue for some reason? It will also not pop once even with a little carb cleaner sprayed down the carb or spark plug hole with or without the choke on or off.

I also took off the muffler and the carb and used the carb cleaner and it still wouldn't even pop once.

The new plug is also slightly wet after using the carb cleaner and I've verified it is getting a spark at least when it's out of the saw so it's not the kill switch either.

I've checked for scratches on the piston and I didn't see any. I also did a thumb test for compression and it seems like it has good compression - at least it felt the same as my other identical saw. But I guess I should get it accurately checked soon.

And the only thing I haven't checked at all is the flywheel and any timing issues. An ideas on what to check/how to check that?

Thanks for any/all help!


Follow-Up Postings:

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RE: Poulan Chainsaw Won't Start

1. My thoughts would be compression (even though you gave it a prelim test) or muffler back pressure.
2. Ck the flywheel key X Timing, Ck carbon or stuck ring X compression, Ck spark arrestor X restriction.


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RE: Poulan Chainsaw Won't Start

The muffler isn't on it so it's not a spark arrestor problem and that was very clean anyway. I think it's a compression issue since there doesn't seem to be much back pressure to it at TDC like my other saw. But I'll check the flywheel key next and report back. Thanks.


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RE: Poulan Chainsaw Won't Start

A good compression test compared should tell you something. In the past, my finger or thumb test has been a good preliminary w/o a gauge close. Basically I have not been able to hold the compression in a small engine that was good. The few that have not passed usually have shown why through the exhaust port vs pulling the cylinder.


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RE: Poulan Chainsaw Won't Start

The flywheel key was fine so I went out this morning and bought a compression testing kit and will be testing it tonight. It's the only thing left I think. Will let you know. Thanks.


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RE: Poulan Chainsaw Won't Start

Check/Match the depth of the threads. I have seen some adapter in sets that would hit some pistons. I always turn by hand first when in doubt.

Good luck on the compression since you have not seen a reason to have bad compression. This could be interesting. Add a little oil if it's low to see if it will come up on 4-5 strokes. A little oil can indicate the rings are not sealing well.

What grade of Poulan saw vs my 70,s S25 that have served me well vs today’s Plastic.


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RE: Poulan Chainsaw Won't Start

Well good news/bad news on the compression testing. My first pull only produced 30 lbs of pressure, then by 5 pulls it was only up to 50 lbs. After 15 pulls it was up to 65 lbs but never got past that even after 50 pulls. In comparison, my good saw produced 60 lbs of pressure after the first pull and got up to 100 after 5 pulls. Btw, this good saw has started on the 2nd pull many times and it was at 90 lbs on my 2nd pull during the testing.

I thought it felt like there wasn't the same resistance in the bad saw. So I now know why it won't start but I'd like to know why. I don't see any scoring but I can't see the whole piston of course. Is the piston ring just worn out now and needs replaced after just 2 years?


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RE: Poulan Chainsaw Won't Start

So I just did the oil test and the pressure did increase some. On the first pull it went from 30 lbs of pressure up to 45 and then to 60 after the 2nd try but then slowed down and ended at 70 lbs after 15 pulls. I also meant to say before that the top of the piston and the exhaust port looked normal. Some carbon but not excessive I don't think. And from what I can see of the walls of the cylinder, it looks fine too.


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RE: Poulan Chainsaw Won't Start

I put a piston/ring set in one of my S25 Poulans that seized/locked after hrs on a 100 degree day. That gave me approx another 10 yrs cutting 2-4 cords approx 20 years. During a PM I felt too much play in the rod bearing and retired it for parts (since I have 2 others with fewer hours). My first had a wrist pin keeper to come off after 10 years. It ruined the cyl which was too expensive vs replacing the saw.

Approx how much time or cords did you have on the saw? I have averaged 2-4 cords since the mid 70s after cutting about 10 one season. Then not one the next due to a Hernia Surgery but had plenty wood.

I doubt I will purchase another gas saw. I’m mainly working pre-cut to lengths 4-12”dia wood cut and left on the curbs for City Bulk Pickup monthly now. The contractors will cut/stack the wood to length knowing it will go fast or load you in the Old Neighborhoods. They chip/haul the brush and all is cheaper to the homeowner that takes that option. I have not needed a gas saw in two years (Thanks to my 14” Electric Mac) but I keep two serviced and ready.


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RE: Poulan Chainsaw Won't Start

I have only cut about 2 cords a year from May to September for the last 2 years so about a total of 4, maybe 5, cords on this one saw. To me, that doesn't seem like much since it was spread out over 5 mo's each year but maybe it is for this particular saw. Should I just bite the bullet and replace the ring and gaskets and see what happens? Most of the trees I am cutting down are dead but they are 12-15" in diameter and oak. Maybe my saw is too wimpy haha.


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RE: Poulan Chainsaw Won't Start

I would look at what you have invested. Poll the Pros here on whether it will take a rebuild or was it designed to be replace. I have just my limited experience rebuilding on the mid-grade saws. Pull the cyl to see if there is minor damage you could not see. See if the need is obvious and reasonable in needed parts cost.

That was a simple evaluation or job and good experience (on my two S25 vs too many mowers etc). The 1st was not reasonable after 10 yrs on the 1st saw. Due the need to replace the cyl the keep wore into. The second had 10 yrs but just needed a Piston and Ring Set (50.00 vs 100.00 if a cyl had been needed). Most Of All! I like to know the cause if at all possible.

Such as: I did use the 1st in 100 degree heat which could have had some influence on the keeper failing. I felt the 2nd failure had two factors, working in 100 degree heat (all ways noticeable hotter) and possibly not a good oil-mix. In the 70s 16:1 was recommended but I might have run 50:1 (from using left over 50:1 Boat’s Mix w/o making it 16:1+).

Since the failures, I try and work when it’s cooler, monitor the engines gas or electric closer and use them shorter periods (mornings, 1-2 hrs above 70-80 degrees). Age has brought on A Natural Monitor. LOL!

How old is your identical saw, approx cords or hrs of use and where were they built? IMO that was not good service, think if there could have been other conditions to influence the failure (bad fuel mix, bad bar/chain, over revving with no load, extreme heat and Etc).


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RE: Poulan Chainsaw Won't Start

i have a similar issue with my newish poulan. it starts and runs but as soon as i press the trigger to adjust idle it stalls dead.

just got it last year it wouldnt stay running on my first attempt so i had it in to a repair shop..it ran ok for a couple of hours, now its doing this.
any thoughts ?
Tex


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RE: Poulan Chainsaw Won't Start

Tex,

1. Approx how long are you storing without using? Are you using and storing with treated fresh fuel. I treat my fuel with Stabil and get a years use w/o a problem. I have heard untreated ethanol fuel will only work for 30 days. I have not experienced this personally.
2. I have seen cases where restricted fuel filters would not allow good fuel flow.
3. Ck all fuel lines for air tight fits and no cracks.
4. Get a close Yardman or friend that use 2-cycles daily to spot check it. They usually have a good feel for problems.

It might be a good idea to start a new post vs this one becoming confusing even though they are relates.

Good Luck! Please share your results.


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