2lumbarleft
ArboristSite Operative
In the just recent past, but perhaps by coincidence, I have run into several brand new looking Poulan chainsaws at garage sales that had scored cylinders. When I inspect saws that don’t start or shut down shortly after warming up, I usually first confirm the problem by looking into spark plug hole with a bright flashlight to view exhaust side of cylinders, and then confirm by removing the muffler and observing both piston and intake side of cylinders. I prefer visual inspection as compared to trusting in a compression gauge reading. Typically, scoring presented itself in a just one heavy vertical black line etched into the cylinder wall rather than many. I have seen this on both the wild thing models and Poulan Pro with the supposedly better cylinder wall coating. Why they continue to ship these saws to box stores in that lean of a condition is surprising.
Most recently, I watched a You Tube presentation from “Donny Boy” repair videos regarding Poulan chainsaw compression. I was surprised to hear that it was common to get readings around 150 psi. I always had thought that compression was probably much lower on those saws, perhaps 125 psi or less, primarily because they come with the blessing of the manufacturer to run 87 octane ethanol gas with 40:1 premix. The manufacturers already know they are running the carbs too lean because of the EPA, so why not recommend using premium gas to the cool the saw down? Another reason that I always thought compression was lower, is because those saws usually seemed to require skip chains to keep the rpms up in the full power range. I tried full comp chains on Poulan PP4218A models, even with the carburetors tuned properly, and they just didn’t seem to provide the required power to properly pull a full comp chain. I decided to run some compression tests of my own, and was surprised to see that the Donny Boy video was right! I consistently got readings averaging around 150 - 153 psi on several saws, and even got 162 on a brand new Poulan Pro 4218A. Here is my point. If compression is indeed that high, why aren’t they producing more power? Also, why in the world would any manufacturer recommend that it was OK to run 87 octane fuel with these compression numbers? Add a little old fuel with diminished octane levels, and the saw is doomed in the hands of the average homeowner, primarily because they refuse to throw out old gas pre-mix.
As far as the lack of power, I have to believe the problem is due to the muffler back pressure. The muffler deflector sure seems restrictive. I know some people out there have opened up these Poulan mufflers, as there have been some pictures in the past. To anyone who has actually done this on a Poulan, I am curious to what degree or percentage one might expect to see improvement in power? I saw a Blsnelling video running a muffler modified Poulan, and it appeared to really rip. However, that guy is a pro, and he probably ported it as well. I would love to hear your opinions. Also, if you are a chainsaw rebuilder, if you have any insights into the internal design of these Poulan engines that would cause them to produce less power, I would be very interested.
Most recently, I watched a You Tube presentation from “Donny Boy” repair videos regarding Poulan chainsaw compression. I was surprised to hear that it was common to get readings around 150 psi. I always had thought that compression was probably much lower on those saws, perhaps 125 psi or less, primarily because they come with the blessing of the manufacturer to run 87 octane ethanol gas with 40:1 premix. The manufacturers already know they are running the carbs too lean because of the EPA, so why not recommend using premium gas to the cool the saw down? Another reason that I always thought compression was lower, is because those saws usually seemed to require skip chains to keep the rpms up in the full power range. I tried full comp chains on Poulan PP4218A models, even with the carburetors tuned properly, and they just didn’t seem to provide the required power to properly pull a full comp chain. I decided to run some compression tests of my own, and was surprised to see that the Donny Boy video was right! I consistently got readings averaging around 150 - 153 psi on several saws, and even got 162 on a brand new Poulan Pro 4218A. Here is my point. If compression is indeed that high, why aren’t they producing more power? Also, why in the world would any manufacturer recommend that it was OK to run 87 octane fuel with these compression numbers? Add a little old fuel with diminished octane levels, and the saw is doomed in the hands of the average homeowner, primarily because they refuse to throw out old gas pre-mix.
As far as the lack of power, I have to believe the problem is due to the muffler back pressure. The muffler deflector sure seems restrictive. I know some people out there have opened up these Poulan mufflers, as there have been some pictures in the past. To anyone who has actually done this on a Poulan, I am curious to what degree or percentage one might expect to see improvement in power? I saw a Blsnelling video running a muffler modified Poulan, and it appeared to really rip. However, that guy is a pro, and he probably ported it as well. I would love to hear your opinions. Also, if you are a chainsaw rebuilder, if you have any insights into the internal design of these Poulan engines that would cause them to produce less power, I would be very interested.
oh never mind, not politically correct......yea you are right.
10x better
