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Chainsaw won't start


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09-22-12, 03:55 AM   #1  
Chainsaw won't start

I am having problems with poulan pro chainsaw.. I have rebuilt carburetor, replaces fuel line and spark plug. Still nothing.. I have tried to put gas and starting fluid in air intake, but still nothing.. I have cleaned carburetor thouroughly still am not sure what the problem could be... the spark plug has spark... Any ideas??

 
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09-22-12, 06:13 AM   #2  
The compression on something like that is usually the culprit. Pull off the muffler and look inside the cylinder to check for scoring on the piston and/or cylinder. If there is you probably don't have the compression you need. It would take about $85.00+ to replace those parts.

 
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09-22-12, 07:22 AM   #3  
One issue that has stumped us time and time again is a clogged spark arrestor screen/muffler. Not sure its the source of your problem, but a real quick and easy thing to remove to eliminate the possibility that it's your ghost.

Good luck-

 
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09-22-12, 02:13 PM   #4  
Do a quick compression test on this saw with a GOOD compession gauge and be done,,if it is under 90 lbs trash it,,,if over 90 lbs it should run. The clogged spark arrestor comes form engine or gas mixture being to rich, if the engine cannot breathe it won't run. Good luck. What has always stumped me is if you dribble a little bit of gas in carburetor and or spark plug hole and it won't fire, whats that deal all about??

 
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09-23-12, 06:31 PM   #5  
Hey thanks for the replys, if the piston is scarred would it not crank at all? I do not have a compression tester but it seemed to have decent compression using the thumb method. Should I try some starting fluid in sparkplug hole to see if it cranks? Is it possible to just be flooded from me trying to crank it? Just trying to get this running for a friend who has helped me our ...

 
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09-23-12, 06:40 PM   #6  
If it's scarred badly enough, no it wouldn't crank up. Is the spark plug wet?


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09-24-12, 02:26 PM   #7  
Hey, got back around to chainsaw today.. it acts now as if it wants to crank but can't get going?? It is not adjustments to carburetor tried that.. I am thinking that it might be still having problems getting gas to carburetor of engine?? what is best way to check this.. i have already replaced fuel line and filter.. any help would be appreciated...

 
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09-24-12, 07:21 PM   #8  
If you're meaning by trying to crank, it's firing and doing a little sputtering trying to keep the rpms going, your compression isn't likely the problem, but the flooding more than likely is.

Take out the plug and spin the engine over about fifteen pulls with the throttle held in full position. Then add a teaspoon of gas/oil to the plug hole, stick the plug back in it, and with full throttle pull on it to see if it will take off. You may have to do another fifteen pulls or so, but keep the throttle in fully open position while you do this.

 
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09-25-12, 01:27 PM   #9  
K i am about ready to shoot this with my shotgun... Every about 15 pulls it acts as if it will sputter, but will not rev up... I will try marbobj what you suggested and see if that will work.. It will hit, but just not get up and go.... could, the flooding really be this problem??

 
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09-25-12, 06:12 PM   #10  
Yep. If you get it to fire, even though your arm is ready to quit, it's not likely a compression problem. Once you get it dried out and started, then you can look at performance/idle issues that could be attributed to carb adjustments, etc.

 
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09-26-12, 02:47 AM   #11  
Could be that your exhaust muffler is blocked. Pull it off and blow through it, check that the exhaust port/s aren't blocked too.

Using correct petrol/oil mix and fresh fuel ?

You say it has spark - just because you see a spark when the plug is removed doesn't mean it is of sufficient quality to fire off compressed mix in the cylinder.

 
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09-26-12, 01:26 PM   #12  
K last night if started to crank, I am feeling as if now I just need to adjust carburetor.. What is the best place to start with adjustments so the machine will crank and allow you to work with the two screws.. If I left it out one turn from all the way in and it still won't stay cranked do I screw in or let out?? And if i do what screw do I screw in or out? Almost there thanks for the help...

 
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09-26-12, 05:42 PM   #13  
Turn both mixture screws in until they lightly seat, then see if it will start. I think it's flooding and you have carburetor problems.


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09-29-12, 12:16 PM   #14  
k, it cranks, sometimes I can get it to idle but when i throttle it chugs and goes dead... How will I adjust screws if they are all the way in cheese??

 
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09-29-12, 01:25 PM   #15  
Try 1 1/2 out from lightly seated on the one marked "L". If it will idle there and die with the "H" screw turned into lightly seated, then turn the "H" out 1 1/2 from lightly seated. If your carb is OK it should run and accelerate to some degree at those settings.

Go back to the L screw and turn it in/out until you get max rpmsat idle. You'll likely have to go in to increase the engine speed. When you get max rpms there, turn the screw back out 1/16 of a turn and leave it.

Then go back to the "H" screw, hold the throttle at fully open and adjust the screw in/out for max rpms. You normally will go in. When you hit the max rpms the engine should snap open quickly on acceleration.

Now make sure you do this. With max rpms on the "H" screw setting, turn it out slightly to drop the rpms from max. Go at least 1/16 of a turn. This will give you a slightly richer mixture for power and cooling. Without doing this final adjustment you can burn up a two stroke, which is what you have in that saw.

Your final adjustment will be to idle with the saw fully assembled with the chain on it. Adjust the idle speed screw (the one that holds the throttle open) until the chain just starts to move. Then back it off slightly.

 
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09-29-12, 09:53 PM   #16  
That'll do it. If it still floods, you have carb problems.


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09-30-12, 11:19 AM   #17  
K I am taking apart carb one more time to clean. Does it matter which screw goes back In adj. h and l. I took them out to clean pretty sure but not positive. When I tested it out had gas spitting from air intake is this normal? It will rev wide open or maybe idle, but want do both, any ideas what any of this means??

 
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09-30-12, 01:00 PM   #18  
Spitting out the intake can be a bad reed valve or a plugged exhaust port or a really leaky carb.If you're getting pressure behind the discharge out the intake, it would be reed valve or plugged exhaust. This is in knowing the engine will start = rings sealing well enough.

 
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10-01-12, 12:38 PM   #19  
k marbobj the engine will start, but will not run.. Like I said it will idle sometimes, and be full throttle sometimes, but will not do both... if Idle it idles for a while and then quits.. I have tried many settings of carburetor, just will not run properly.. Does a poulan pro 375 have a reed valve?? If so where can I find it?? This is so annoying, I just want the machine to run.. The exhaust port is not clogged i can see the piston very well.. Any ideas?? thanks... Cheese, I have tried the adjustments that you said and yours marbobj for the carburetor but none still did not work well... please help someone if you can thanks...

 
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10-01-12, 01:02 PM   #20  
Bad fuel

How old is the gas and oil mixture? Did the saw have fuel in it from a prior season? Are you sure the fuel oil mixture is correct?

If the problem is when it is cold, it may be there is to much oil in the mixture causing fouling.

If the problem is when it is hot, you may have to little oil in the mixture and the saw is struggling to be lubricated.

Check the condition of the spark plug, does it look burnt, or oily? How old is the spark plug. Is your ail filter old or clogged?

Does the motor spin easily when the plug is out, if not it was partially siezed due to lack of oil in the mixture.

IS the clutch for the chain clean and lubricated? IS the chain lubrication working? Is the chain bar clean and lubricated? Chain tension to tight or to loose?

Before adjusting or changing carb or jet settings, please do all the above evaluation because if it was bad fuel and you adjust things, it will be difficult to get it running correct again. Also, only ajust one thing at a time.

 
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10-01-12, 05:44 PM   #21  
In terms of cleaning the carburetor, how far apart did you take it to clean it? Also did you change the fuel filter in the tank and make sure the gas cap is venting OK.

It could be to the point of either putting a kit in it or replacing the carburetor. If you have good fuel, as mentioned, and the base adjustments aren't working in the normal range, at least a kit would be in order. This would have a diaphragm for the pump and one for the reservoir and a few other replacement parts.

Along this line of thinking, the diaphragm for the fuel pump may be stiff and not able to work properly unless the engine is driving it at the higher rpms.

No reed valve on that one. It likely has piston port timing.

 
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10-01-12, 07:14 PM   #22  
hey, I took the carburetor apart and replaced all parts with kit...Using new gas and oil... how do I check the gas cap venting?? anything else i can check??

 
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10-01-12, 07:39 PM   #23  
Just loosen the cap and see if it changes anything. You have changed the filter inside the tank?

While it's idling, spray some wd 40 around the carb gaskets that mate it up to the engine. If it changes the running of the engine you likely have a gasket leak.

 
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10-01-12, 07:57 PM   #24  
hey, yes i changed the filter inside.. I will try the wd 40.. spray it where the carb meets engine?? I also noticed that when it does run at idle the engine speeds up slows down, speeds up...then after a short time of that it goes dead.. Does this help any??

 
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10-01-12, 08:24 PM   #25  
Still sounds like a carburetor problem to me. Sometimes making adjustments and adding new gaskets isn't enough. It may need more cleaning, or the metering lever adjusted or replaced, or another carb.


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10-04-12, 07:41 AM   #26  
How do you adjust the meter level Cheese?? Could these problems have anything to do with the clutch, or saw??? also, because this chainsaw is so old any ideas on where i could order a new carburetor or at least get parts number for it??

 
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10-04-12, 09:35 AM   #27  
When an engine speeds up and slows down, then stops, it means it's running out of fuel. The saw parts of what you have (bar/clutch/chain) wouldn't be involved, although those parts have to be working properly to have a working saw.

In a crankcase fed pulse pump carburetor like you would have, you need the crankcase pressure to be correct (crank seals not leaking), the path to the diaphragm of the pump to be clear and non leaking, and the diaphragm itself to be flexible to do the pumping of the fuel. On the carburetor side of the pump it needs to be clean to allow the fuel to pass through, be metered properly, and vacuum tight as different pressure variances are part of the design to allow it work.

You can check the vacuum/pressure leaks with the WD40 or something similar.

A 375 Poulan Pro isn't an ancient saw. I have not only PP 250 but a 306 (which is ancient) and both run very well.

IF you're really into fixing a carburetor, you could likely handle the metering rod adjustment, but a lot of novices simply keep the old one when they install the new kit. If you put in a new kit, you would have run across the metering rod. How did you handle that?

 
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10-05-12, 07:27 PM   #28  
Hey I took carb apart and replaced needle. Marvbob what would the wd 40 do ?? Just spray it on that part of carb ?? Do you think seafoam might help? I still think there is somerhing wrong with carb what is best way to deep clean it .. I can't fi
d part number for new carb Boone can find it in our shops ?? Any ideas to any of this ??

 
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10-05-12, 08:21 PM   #29  
If you replaced the metering arm/rod, you'll need to adjust it get the right amount of fuel held in the fuel reservoir. What is the make/model number of the carb?

Spraying the WD40 around the carb gaskets and crank seals while the engine is idling is a good way to check for vacuum leaks. Don't spray it into the intake of the carb, but around the gaskets that are between the carb and the engine cylinder.

At this point you've replaced the filter, the fuel lines are pliable (not stiff and brittle), and you've put a kit it with the diaphragms and new metering arm (which needs adjusted). Is there a primer bulb on that saw?

You've also tried loosening the cap to check for tank venting.

Now it still runs for a short time, then dies. Will it run wide open for any period of time - chain and bar mounted? Chain is lubed and spins free?

How long ago was that saw running well? Did it sit unused for a long time?

 
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10-06-12, 02:35 PM   #30  
K it will run currently full throttle.. No idling still spitting gas out air intake at least to begin with how do you adjust metering lever? Shouldn't it be level with something? Thanks for your replies

 
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10-06-12, 03:24 PM   #31  
You usually need the make and part# of the carburetor for the settings. Did you go through the base and tune procedure I gave you for the High ("H") and Low ("L") mixture screws. If you did, then you still have a full throttle working, but not the low speed/idle?

You can try Sea Foam. I use it in a lot of stuff with good results, but it won't take the place of mixture screw settings or setting the metering arm.

If you use the Sea Foam only run a 32:1 oil gas mix in the tank full you use the Sea Foam in.

Let me check a couple places for the metering arm setting. I may be on a Poulan site.

 
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10-06-12, 04:23 PM   #32  
Here's a U Tuber for you on a Walbro rebuild. That's likely the make of yours, but no guarantee. I have a Walbro on my 250.

Rebuilding Walbro Carburetor (Chainsaw) | Free Auto Vehicle Repair Videos at VehicleFixer.com - Find your inner mechanic

I tried the "click on" it should work.

Where he's measuring the metering arm, he should have put some pressure on the needle valve to fully seat it and the pivot pin. Just set your new one in that manner.

 
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10-07-12, 12:31 PM   #33  
k, it idles fine, but will not work full.. it seems as though it wants too, just at beginning then falls off and dies if i give it full throttle.. i tried wd 40 to spray where you said. it seemed to at least rev up some when i pushed throttle.. the gasket on end of carburetor where the carb meets engine, should i replace that?? think it could be my problem?? i will check the video out for pin setting.. making throttle adjustments, seems to at least let engine run... If i ever figure this out, i will truly have learned so much about chainsaws.... I also noticed that when i make adjustments to carb with it idling, seems the engine made no adjustment what's up with that??

 
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10-07-12, 01:26 PM   #34  

k, it idles fine, but will not work full.. it seems as though it wants too, just at beginning then falls off and dies if i give it full throttle..
Normally if it will not throttle up from idle, adjust the L screw out 1/16 turn at a time.
i tried wd 40 to spray where you said. it seemed to at least rev up some when i pushed throttle.. the gasket on end of carburetor where the carb meets engine, should i replace that?? think it could be my problem??
If it idles but revs up a bit when you spray a certain gasket (make sure you are not spraying into the carb at the same time) then that can indicate a leaking gasket which is sucking air and will not allow carb adjustments to be consistent or effective. If that is the case, yes replace the gasket.
I also noticed that when i make adjustments to carb with it idling, seems the engine made no adjustment what's up with that??
The adjustments do not effect idle per say, L adjusts the transition from idle to high RPM, (when you pull the throttle it revs up smoothly without stumbling) the H adjusts for full throttle mixture. I generally try to adjust for max rpm then work on the step up off of idle. I like to use 3/4 to 1 turn from lightly seated myself to begin with, but the other steps mentioned are the same. If you do have a vacuum leak, the adjustments will only frustrate you as it will not be consistent.


Read more: http://www.doityourself.com/forum/ou...#ixzz28e7yEAZH

 
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10-07-12, 06:56 PM   #35  
The L screw should make a difference at idle, but the H won't so much. Try backing out the h screw a little and see what happens. Since it tries to rev and then falls off, that tells me the H screw is the one needing backed out a bit, or the H circuit isn't getting enough fuel for some reason.


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10-07-12, 07:25 PM   #36  

The L screw should make a difference at idle, but the H won't so much. Try backing out the h screw a little and see what happens. Since it tries to rev and then falls off, that tells me the H screw is the one needing backed out a bit, or the H circuit isn't getting enough fuel for some reason.

God bless!


Read more: http://www.doityourself.com/forum/ou...#ixzz28fcnPMS8
What good will that do if he has a leaking intake gasket?

 
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10-08-12, 01:10 AM   #37  
Not much, but I didn't see that the intake gasket was leaking. He said "i tried wd 40 to spray where you said. it seemed to at least rev up some when i pushed throttle.." Which is inconclusive. "It seemed to" and "when I pushed the throttle". Spraying around the carb while pushing the throttle will get a tiny bit better response regardless of the gasket because it will pull in aerosols from the spray that close to the carb. If it revved up nicely while spraying that gasket, then I'd be convinced it was the gasket.


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