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poulan trimmer will not run w/ choke off?

Posted by pgtr (My Page) on
Sun, Apr 3, 11 at 18:09

Someone gave me a barely used (8ish yrs old) Sears 32cc straight shaft string trimmer for string or blades. The fuel lines were rotted away but other than that it appeared to be fine and looked to have only been minimally used perhaps a couple few times.

What I've Done:
I've replaced the lines, filter, primer bulb, inspected the plug, cleared all the passageways in the carb with carb cleaner (appeared to be quite clean) and added fresh 40:1 fuel (w/ Hursqvarna 2 cycle oil). Pulled and inspected the intake manifold (it's plastic!) and appears clear of obstructions etc. Pulled, inspected the muffler (only held on by springs) and it's clear and like new w/o even any external surface rust yet. The line w/ the filter has several inches inside the tank allowing the filter to flop around a bit so it's always well submerged in the fuel when holding upright. I did leave a couple inches on the return line in the tank (should it be trimmed to only extend a little into the tank? or does this matter? - I don't see how it does - but just asking...)

What It's Doing:
Following the instructions to prime, sputter in full choke, flip to half-choke - fires up, wait a while and no joy when switching to choke off.... It actually runs fairly well in half choke. It's a little boggy as you might expect but if you're slightly slow on the trigger (take a second vs a fast squeeze) it runs up the RPMs fine. After running 10, 20 or more minutes I've tried flipping the choke off from idle, part throttle or full throttle - stalls out every time within 1, maybe 2 seconds. I've tried it w/ the air filter installed and removed.

Mixture Settings:
The mixture screws on the Walbro carb are recessed within a boss and only have finely serated outer edges, no cross or Philips pattern etc. E.g. it appears to be designed to only be adjusted w/ a factory specialized tool and probably intended to be left alone. I 'could' cut off the boss and cut slots in the mixture screws if necessary. It should be at the original factory settings and it probably has less than a couple/few hours on it since purchased new.

Anybody encounter a similar problem or have any further suggestions? I could modify it to adjust mixture screws...? I could also just run it at half choke all the time...?


Follow-Up Postings:

RE: poulan trimmer will not run w/ choke off?

Is that the model that has the spark plug on the bottom?

IF so good luck getting it to run good without pulling the splined adjustment screws and notching them for screwdriver. It either running way lean or the carb. still plugged up under the welch plug. (under the welch plug you have three jets. Idle, mid throttle and full throttle.)

I had one of them and never liked it even after I got the screws sloted. You can find the splined mixture adjustment tool online. Ebay has them from time to time.

RE: poulan trimmer will not run w/ choke off?

ptgr: I would say fuel restriction again , if you have as indicated done your homework on the carb circuit cleaning , then as rc has advised the jets need adjustment . 1st you
have to ensure that the Priming Circuit is clean I know I have advised you of this previously so no use in trivia. But prior to further inspection ensure that the bottom diaphram is still within spec. Inspect for any small tear or hole or deformation (stretch) which will also cause your symptoms. Next you must remove the High and Low speed jets and clean thoroughly with carb cleaner and compressed air . Then set both High and Low initally at 1-1/4 turn out from closed .
You can as rc has recommended buy the D , DD , Splined and Pac Man Carb Adjusting Screw Hand Tools on Ebay for just under $20.00 for the set . Otherwise just slot the heads accordingly . The 1-1/4 out should get you up and running . Tune the Low speed jet 1st turn jet in or out slightly until there is no hesitation upon throttle response. Next set the High speed jet turning it in or until max. rpm is attained , then turn the screw out slightly until it diesels , this will ensure a not to lean mixture . Last but not least once warmed up set the idle speed so that head just barely rotates when warm this should give you a good idle speed when cold without unit stalling . All the Best !

RE: poulan trimmer will not run w/ choke off?

Indeed! It is that exact model w/ the plug ON THE BOTTOM and the 'updside down piston'. Thanks for the sanity checks guys - at least I know it's not just me.

It vibrates like crazy (Googling suggests this is common w/ Poulans) but it's a pretty good cutter w/ the choke in the HALF position.

Thanks for the tip on the tool(s) - I'm on the fence - the Poulan Walbro carb tool (P/N 530035560) is a bit less but still... Are the other three oddities worth considering? The D, DD and PacMan? What year(s) did these tools get phased in and on which brand(s)? Are there still carbs fitted w/ non tamper resistant adjustments?

Visually the diaphragm appeared OK under a glass but as far as deformation - that's a bit hard to say...? I had a half a thought to source a carb kit for the gasket previously - so I may google up some options and consider that.

thanks for the responses. Again, good to know others have seen this phenomenon.

RE: poulan trimmer will not run w/ choke off?

Now you know why they gave it to you, it never ran right to begain with probably?

The kit is worth it if you have the means to use them. If that diaphramn is hard that could be problem also? But, that usually supplies the initial burst of fuel through the carb. which it may not be doing with all three jets require fuel flow? I'm one the fence on that one?

IMO that's no phenomenon with that trimmer after the EPA carb. change rules to prevent homeowners for adjusting carb. But free you have alittle room to work with.

RE: poulan trimmer will not run w/ choke off?

I used a hacksaw to remove the boss around the adjustment screws and notched each adjustment screw. Trivial - just a couple few minutes. Opening up the H screw about 3/4 a turn made the difference.

I still may need to tweak the idle settings a tad but it runs decently enough. It definitely vibrates more than one would want to experience for extended usage.

Rather than running it dry before storing - I dumped the unused gas back into a storage container and hit the primer to pull out most of the remaining fuel from the carb/lines.

RE: poulan trimmer will not run w/ choke off?

Wow 3/4" is a lot! usually it's about 1/8 to 1/4 turn? But if it runs good can't beat free! I wouldn't let it set too long without using it or you maybe back to square one.

RE: poulan trimmer will not run w/ choke off?

I would add a cap full of Marvel Mystery Oil to each tank. It will help out dried out rubber parts.

RE: poulan trimmer will not run w/ choke off?

My bad - it WAS a quarter turn as in 1/4 - NOT 3/4 - that was a typo!!!

Thanks for the tip on MMO - I have some around in fact.

RE: poulan trimmer will not run w/ choke off?

My 1 year old Poulan trimmer absolutely would not run off choke no matter what I did to the carb. Just yesterday I took it out to the concrete driveway, smashed it, then ran over it. I feel so much better now. My new Robin NB2050 trimmer weighs only 8 lbs. and runs perfect.
........C'est la vie, Poulan.

RE: poulan trimmer will not run w/ choke off?

hey rdaystorm, are you getting too much rain!?!. I feel for you I did the same thing to cheap sears trimmer two stroke about 15 years ago, I too felt relieved I didn't have to pull that rope again.

My wife thought I was going off my rocker. Well, she was part right. three years later I was dianosed with brain tumor that was pushing on my brain causing several systems to go haywire. I attributed my moment of weakness to the tumor which evenually caused me all sorts of problems. rage was one of them. Luckily I made it through it.

RE: poulan trimmer will not run w/ choke off?

Roflmbo I usually leave the cement repair procedure to Polan Chainsaws ..sorry ptgr lol .

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