Mystery poulan

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Rfarr1994

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I’m sure it’s no mystery to some of you but I just bought a poulan off of Craigslist no decals left. I tore it down and it has a 48 mm cylinder bore so I’m thinking a 3700 but I’m new to older poulans.
 

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Not a very good picture of the piston but it has the thin rings. I paid 25 for it and it needs an ignition coil and an air filter so if I can get it running i feel like I did pretty good.
 

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Thanks for the link, I guess someone robbed the coil for another saw because it was completely gone when I opened it up
 
Waiting on parts but putting it back together and cleaning as I go. The bottom end is lined with 40 years of crud. Don’t think just soaking and compressed air will clean it. Don’t have to tools to split the case and never done it before. Should I try and clean it or run it like it is?
 

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It's about the easiest case you'll ever split. 9 Phillips head screws and a little persuasion. no special tools required.

It goes back together with a fuel resistant sealer like Permatex Motoseal grey.

I'll PM you a link to a decent repair manual. You will see a little green envelope beside the bell and magnifying glass top right of your screen to pick up the message.

If you don't want to split the case, pour a bunch of mix into the crankcase and use that to clean it out.
 
I split the case and it was really easy. Got the saw all back together now just waiting on the coil to arrive. One thing I need to fix is the oil pump. I took it apart and cleaned the pump it sounds like it’s pumping but no oil is coming out. Can you buy replacements or is there any way to fix the pump?
 
Got the coil in today and got home tonight just in time to install it and get the saw started for the first time since I’ve owned it. I only ran it for a minute and didn’t have the bar on so I don’t know if the auto pump works I know the manual pump sounds like it is trying to pump. Don’t know if I need to prime the pump or something. also I’m used to running newer 50cc stihls and husqvarnas so I don’t know if it’s normal for a saw this age or maybe I don’t have the muffler seated all the way but this saw is at least twice as loud as any other I’ve run and the muffler is still stock.
 
You should pull the auto pump off and check the pickup line. They are often torn or cracked or have fallen off due to age. Don't forget to empty out the oil beofre you pull the pump or you will have a mess.
Clean the screen on the end of the line. Pay attention to the manual. The hose needs to be in the right part of the tank.

If the auto oiler doesn't pump you may need new gaskets and a pump diaphragm. Someone on the Poulan stickie thread is making pump diaphragms as they are very difficult to find.
https://www.arboristsite.com/community/threads/niks-poulan-thread.98495/page-2853#post-7491827
Just a cautionary note. Don't run them with no bar and chain as the clutch can spin off at light speed. A bunch of us have done that. Broken lights and other stuff or clutch parts all over the garage. I hear the parts can go 100 feet. I'm still looking for a clutch shoe.

You don't need the clutch on to test run for the oiler. LH thread on the clutch.
 
I had the bar on and ran it manual pump will not pump and no oil being throw off the tip of the bar from the auto oiler so it seems neither work. When I had the saw apart I took the oil assembly apart and cleaned all the old crud out of it. The diaphragm looked normal to me but I don’t really know what I’m looking at. I think I’ve read on here the auto oiler is impulse driven? I don’t know what that means or how it pumps oil
 
There is a hole in the saw case under the pump that leads into the crankcase. As the piston goes up and down there is negative and then positive pressure in the crankcase. The spring loaded pintle in the oil pump (under the diaphragm) is pulled down with crankcase vacuum (piston going up) and then the spring forces it back up. for another cycle.

There is a check valve in the pump which keeps the oil from being pulled back into the tank as the diaphragm pulses.

Any air leaks in the oiler system will not allow it to work.

I hope that make sense.

Did check the oil pick up line in the tank?
 
That makes sense. I’ll have to pull the pump back apart and take a better look at everything and clean it better. I never looked at the check valves when I had it apart the first time. I think I read on the poulan thread about soaking the diaphragm in oil overnight.
 
You should pull the auto pump off and check the pickup line. They are often torn or cracked or have fallen off due to age. Don't forget to empty out the oil beofre you pull the pump or you will have a mess.
Clean the screen on the end of the line. Pay attention to the manual. The hose needs to be in the right part of the tank.

If the auto oiler doesn't pump you may need new gaskets and a pump diaphragm. Someone on the Poulan stickie thread is making pump diaphragms as they are very difficult to find.
https://www.arboristsite.com/community/threads/niks-poulan-thread.98495/page-2853#post-7491827
Just a cautionary note. Don't run them with no bar and chain as the clutch can spin off at light speed. A bunch of us have done that. Broken lights and other stuff or clutch parts all over the garage. I hear the parts can go 100 feet. I'm still looking for a clutch shoe.

You don't need the clutch on to test run for the oiler. LH thread on the clutch.
I put the side cover back on without the bar to check for oiling, when that clutch flys off it's never fun!
 
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