Poulan Chain Saw Won't Rev High Enough

otis_xing

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I have a Poulan 18" chain saw that I purchased from Lowe's circa 2010. It has become hard to start and won't stay revved up long enough to cut anything, the rpm's die down after just a second or two. Does the carb just need a good cleaning? I welcome any suggestions, it is worthless in it's current state.

Thank you.
 

bt3

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Howdy.

I'm highly experienced with Stihl, and have no experience with your Poulan, however, let's try a few things.

Gum and varnish in a 2 stroke carb, especially a chainsaw carb are often the culprits of loss of horsepower (revs) when throttle is engaged. Some will idle OK, but die under load. Before you tear the carb apart, take off the air filter and get a bright light source and look into any ports you can to see if you can see any issues. Get a Carb Cleaner and spray it into any ports and openings. Start the saw and see if this has helped. If not, then you can pull the carb and check out the ports, needle valve, etc. It sounds like a clog or gum issue to me.

I assume you have made sure your air filter is clean, yes? Also, I don't know if you have a spark arrestor screen on the muffler output like a Stilh, but those are notorious for clogging and reducing horsepower. I am also assuming your spark plug is fresh and working well, and that your Magneto is generating good spark. Finally, I am assuming you have good compression and no clogging of a fuel filter. These are all basic things that I assume you have thought of or checked.

Fresh fuel is KEY. Dump out your old fuel and put in fresh mixed fuel. In my opinion, You should invest in a can of Stihl or Husqvarna PREMIXED High quality canned fuel. It's worth a try. The stuff has a shelf life or "machine life" of up to 24 months AFTER opening the container, it's very high Octane, AND, guaranteed to have NO ethanol or similar additives. This no gumming or clogging of the carb when it sits.

When I run Stihl MotoMix in my saw, it runs better. There is NO denying that. It literally runs like a top with perceived higher revs with MotoMix fuel. And the fuel will not gum, clog, or go stale like other user mixed fuels. The oil mix ratio is also spot on with very high quality 2 stroke oil mixed for you, and I can leave it in the saw for up to 2 years without worry.

PS, I am NOT a Stihl employee nor a stockholder. I just happen to own their saw and like their MotoMix premixed fuel. It's amazing stuff. Now, if you are a professional Arborist that blows through 5 gallons of 2 stroke fuel a week, it's far too expensive, but for a home saw user? It's worth every penny. It's all I run any more. Amazing stuff.
 

ILENGINE

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As a poulan tech I see this all the time. With the unit being a 2010 the problem could be anything from a cracked fuel line, at the fuel filter, allowing dirt to get into the internal carb screen. A clogged screen in the muffler, which on some of the newer units is not cleanable, and will require replacing the muffler. The carb being out of adjustment, which happens about 99% of the time, because they are too lean from the factory, and about need adjusted out of the box. the complete carb for you saw runs in the 30-40 dollar range, and in most cases isn't worth repairing. If you have a primer which I suspect you do, there will be a 50-50 chance that the check valves in the carb will stick open and then will won't prime, and you will have to replace the carb any way.
 

motoman

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Great thread responses. Readers be grateful for free professional advice.:thumbsup:
 

otis_xing

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Thank you gentlemen for all of your responses. I will work my way through the list of possible causes, starting with the cheapest/easiest fixes. Thanks again for all of the suggestions.
 

otis_xing

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Howdy.

I'm highly experienced with Stihl, and have no experience with your Poulan, however, let's try a few things.

Gum and varnish in a 2 stroke carb, especially a chainsaw carb are often the culprits of loss of horsepower (revs) when throttle is engaged. Some will idle OK, but die under load. Before you tear the carb apart, take off the air filter and get a bright light source and look into any ports you can to see if you can see any issues. Get a Carb Cleaner and spray it into any ports and openings. Start the saw and see if this has helped. If not, then you can pull the carb and check out the ports, needle valve, etc. It sounds like a clog or gum issue to me.

I assume you have made sure your air filter is clean, yes? Also, I don't know if you have a spark arrestor screen on the muffler output like a Stilh, but those are notorious for clogging and reducing horsepower. I am also assuming your spark plug is fresh and working well, and that your Magneto is generating good spark. Finally, I am assuming you have good compression and no clogging of a fuel filter. These are all basic things that I assume you have thought of or checked.

Fresh fuel is KEY. Dump out your old fuel and put in fresh mixed fuel. In my opinion, You should invest in a can of Stihl or Husqvarna PREMIXED High quality canned fuel. It's worth a try. The stuff has a shelf life or "machine life" of up to 24 months AFTER opening the container, it's very high Octane, AND, guaranteed to have NO ethanol or similar additives. This no gumming or clogging of the carb when it sits.

When I run Stihl MotoMix in my saw, it runs better. There is NO denying that. It literally runs like a top with perceived higher revs with MotoMix fuel. And the fuel will not gum, clog, or go stale like other user mixed fuels. The oil mix ratio is also spot on with very high quality 2 stroke oil mixed for you, and I can leave it in the saw for up to 2 years without worry.

PS, I am NOT a Stihl employee nor a stockholder. I just happen to own their saw and like their MotoMix premixed fuel. It's amazing stuff. Now, if you are a professional Arborist that blows through 5 gallons of 2 stroke fuel a week, it's far too expensive, but for a home saw user? It's worth every penny. It's all I run any more. Amazing stuff.


I have checked the air filter; it is fine. The spark plug seems very clean. I have sprayed a ton of B12 in the carb and it did help just a little. It will rev somewhat higher now and for a longer period of time, but not an extended period of time.

Two things that I have noticed is that it will only start while half-choked, even after the engine is warm and that it dies almost immediately if not kept level. In older models that usually meant there was a problem with the float sticking, but I don't know in these newer models. I am going to check the fuel filter next and replace the spark plug. Any other suggestions?
 

possum

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There is no float on poulan chainaws. Check your primer bulb and fuel lines. See if the filter has broken off and is laying in the tank. Pump the primer bulb and see if fuel is coming into the tank. If fuel has been left in it much then the carb is more than likely shot as already has been mentioned. The more often you use a cheapo Poulan the better off you are.
 

bt3

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Other than checking the fuel filter and fuel lines, I'd definitely check the Spark Arrestor Screen just behind the muffler to make sure it's not clogged. The exhaust ports and screen must be clean. Otherwise a 2 Stroke will not generate any power or high RPM.

Finally, other then filter and Fuel delivery issues, I would suspect gum issues in the Carb itself. If all else fails, pull the carb and check all ports for gumming and clogging. Clean them out completely if and when you find clogs and gumming.

If all that has been discussed fails, I'd then suspect low compression issues, I.E. Worn Piston Rings. However, from your description of spraying in carb cleaner, I'd lean more heavily on suspecting carb/fuel/exhaust issues.

Again, this is why I prefer MotoMix Pre-Mix fuel. Perfect suspended lubrication at the right ratio with no separation or deterioration within 24 months after opening.

I agree with Possum that the more you run that saw (within reason) the better. This is true of many 2 stroke motors. AND AGAIN YET ANOTHER REASON TO LIKE MOTOMIX! Many issues revolve around stale or poor quality fuel that is deteriorating and gumming up the lines, carb and exhaust ports. Most of the fuel purchased from the pump and mixed on your own is not good to leave sitting in your saw for any length of time, unlike MotoMix that you can leave in your saw for up to 24 months.
 

Jack17

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I'm currently using Poulan Wild Thing 18" that I bought back in 1997. One thing I've learned over all these years of using it is that they don't like any sawdust in their air filters...at all!!! Pull an air filter out and try to start it up without it. Just so you know (in my case) original fuel lines lasted 12 years before replacement was needed.

P.S.
Almost forgot. My saw won't start with a choke ON and I was unsuccessful in adjusting the carburator to make it right. I think that the carb is just worn out and it really needs replacement. The way she starts now is: Choke OFF. Prime the bulb. Throttle fully open and locked with the trigger lock. Two - three pulls she fires up full speed ahead. Be careful, chain goes around real fast! Moment she starts unlock trigger, bring it back to idle and warm it up a little...and you're good to go.:wink:
 

motoman

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Wonder why my 18" Husqy chainsaw is so hard to pull start, even with the compression button pushed?? It runs fine one started. Thanks
 
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