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I posted an earlier thread about problem sith my old poulan chain saw. The model is S25. I received several responses and appreciate each one. On my earlier thread titled Need Help With Old Poulan chain saw i listed all the thing I have done to the saw and all parts which I have replaced.
I had some time this morning so I went to the shop took the spark plug out and tried the pull rope. The engined pulled very easily and with no resistance completely through the pull. I replaced the plug, LEFT OFF THE PLUG WIRE and tried to pull the rope. It felt like the engine had 300 pounds of compression. By jerking hard on the starter rope it will move only a few inches. I do not understand this at all.
I have my original owners manual for the saw but it isn't much help. Does anyone know where I might find a complete repair manual for the saw?

All help and suggestions will be greatly appreciated.

Frustrated Texan and yes we all still need rain.

wilburn cox said:

I posted an earlier thread about problem sith my old poulan chain saw. The model is S25. I received several responses and appreciate each one. On my earlier thread titled Need Help With Old Poulan chain saw i listed all the thing I have done to the saw and all parts which I have replaced.
I had some time this morning so I went to the shop took the spark plug out and tried the pull rope. The engined pulled very easily and with no resistance completely through the pull. I replaced the plug, LEFT OFF THE PLUG WIRE and tried to pull the rope. It felt like the engine had 300 pounds of compression. By jerking hard on the starter rope it will move only a few inches. I do not understand this at all.
I have my original owners manual for the saw but it isn't much help. Does anyone know where I might find a complete repair manual for the saw?

All help and suggestions will be greatly appreciated.

Frustrated Texan and yes we all still need rain.

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you got the right plug in it? piston hitting the plug?

If you place your thumb over the spark plug hole then slowly pull the rope. Is it still hard to pull? Is flywheel binding on coil or cover?

Wilburn, A long shot. If the saw is old it probably has transfer ports cast in the crankcase. Are they somehow blocked? If yes, then the empty spark plug hole gives the only relief to compression. With plug in you are forcing air past the piston rings which is difficult. Wrong piston fitted without cutouts on skirts?Someone chime in here.:anyone:


I wish we could share some rain. 52 inches since Sept, 12 inches this month

Mikel1 said:

If you place your thumb over the spark plug hole then slowly pull the rope. Is it still hard to pull? Is flywheel binding on coil or cover?

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Thanks Mike;
Yes, if I place my thumb over the plug hole the starter will pull but I can feel a lot of pressure on my thumb. No, the flywheel is not binding anywhere.

Thanks for your question and offer of support,
Red Cox

motoman said:

Wilburn, A long shot. If the saw is old it probably has transfer ports cast in the crankcase. Are they somehow blocked? If yes, then the empty spark plug hole gives the only relief to compression. With plug in you are forcing air past the piston rings which is difficult. Wrong piston fitted without cutouts on skirts?Someone chime in here.:anyone:


I wish we could share some rain. 52 inches since Sept, 12 inches this month

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Thanks Motoman; The saw is old. I won it in a sales contest in about 1978/1980. One reason I like the saw is that it is all metal, no plastic like my newer saws. I have had the saw completely disassembled but I am not familiar with transfer ports in the crankcase. Are these ports small holes such as with carbs??
As for the piston..and cut outs on the skirts. I could not find a NEW PISTON AND CYLINDER FOR THE SAW so I ordered a used set from a place called "Chain sawr". The piston and cylinder was an exact match for the original ones in the saw.
Your are correct, the EMPTY spark plug hole allows the pull starter to move the piston and everything freely without any hesitation. With the plug installed and plug wire off then the starter is extremely difficult to pull and it feels like the whole crankcase is full of air. I took the muffler off this morning and with the plug installed I don't think any air was coming through the exhaust port.
You could be right about transfer ports but I, being honest would not know what to look for if I dismantle the engine again. Any help appreciated.

Here is what I did to the saw last year and then just placed it on the shelf while getting busy with other things.

Completely dismantled the saw BUT did not remove the piston rod from the crank shaft. Carefully cleaned all parts of saw.
New parts installed,
1. New chain sprocket
2. Soaked carb. and installed new carb kit and all gaskets
3. USED PISTON AND CYLINDER ordered from "Chainsawr" these were in great shape, clean and matched original ones in saw , installed new rings
4. Replaced all gaskets including cylinder and crankcase
5. Disassembled gas tank, cleaned and added new gasket, fuel line and new filter inside tank
6. New dust shield and air filter
7. New flywheel key
8. New oil cap on on bar oil tank
9. New pull starter pulley and rope.
10. I DID NOT DISASSEMBLE THE DIAPHRAGM OIL PUMP supplying oil to the bar and chain.

I have three mowers. a Kubota tractor and several pieces of equipment which I repair, rebuild and keep running bur I have never had a problem like this. That's why I am determined to get this little saw back in good condition. My wife says it's a "Man thing"

thanks for any help

Red Cox

tomsteve said:

you got the right plug in it? piston hitting the plug?

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Thanks tomsteve; yes the plug is correct and there is no indication the piston is hitting the plug no odd sound and no bent tip on end of plug.

Thanks for your input; Greatly appreciated

Red Cox

What about the cylinder gasket? Were they identical as well? Did you make one? Just use sealant?

Fish said:

What about the cylinder gasket? Were they identical as well? Did you make one? Just use sealant?

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Thanks Fish. The cylinder gasket was a new one. I did not use sealant. The original cylinder gasket on the saw was stuck and when I removed the cylinder it messed up the old gasket. I could not compare it to the new one.

Thanks again for you response.

Like I said earlier, you either have excess fluid hydro-locking the piston, or something has changed the ratio in some way, like excess carbon, different stroke or different piston, or closer fit of the cylinder to crankcase that would change the ratio. there were many models that were real close to this one, maybe you have a slightly different crank/piston, etc...

Check out those threads I sent you in the p.m., there are some serious poulan nuts there that could probably help, they love those old Poulans.

Fish said:

Like I said earlier, you either have excess fluid hydro-locking the piston, or something has changed the ratio in some way, like excess carbon, different stroke or different piston, or closer fit of the cylinder to crankcase that would change the ratio. there were many models that were real close to this one, maybe you have a slightly different crank/piston, etc...

Check out those threads I sent you in the p.m., there are some serious poulan nuts there that could probably help, they love those old Poulans.

Click to expand...

Thanks again Fish. There are no fluids in the saw at this time, has been dry for several days. No carbon anywhere. Piston & cylinder were replaced with a used set ordered from "Chain Sawyr". Piston and cylinder were a match for the original from the saw. Motoman answered earlier today and said some of the old saws had transfer ports cast in the crankcase and they might be blocked. I have no idea what transfer ports are. Are they tiny holes such as carb. passages?? I will check this out as I have some more time.
I appreciate the 2 forums you mentioned and I did register for the "SawHawgz.com. I have not yet posted my situation on their forum but will shortly.

Appreciate all of your suggestions.

When you took the exhaust off could you see inside the cylinder?

Jrleddy said:

When you took the exhaust off could you see inside the cylinder?

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Thanks JrLeddy; Yes I could see inside the cylinder and it was clean and not scored. Piston (portion I could see) was clean.

Red Cox

Wilburn, I am certainly not an expert on 2 strokes and did talk partial trash about piston skirts. It's the piston crown which acts like the intake and exhaust valve. I have been on line and will offer the following that might help.

Compression is surprisingly high if a you tube is to be believed 190 PSI on a rebuild. Yikes.

My own Husky has a compression release which I use. It really makes a difference in starting. The web is full of examples of compression releases. If yours is too old to have one it may be you are feeling "normal" compression ? During a portion of the stroke both the cylinder head and the crankcase are under compression.

Transfer ports are part of the two stroke engine. In the really old days that's all there was. Reed valves are widely used now and sit in the intake runner back of the carb. But they apparently would not give your symptom.

Fish has apparently suggested some online refs. I will add "indianmcinfo.com" and "pilotfriend.com" for excellent cutaways and animation of the 2 stroke operation. Might help.

There is a forum member who said he was the "two-stroke dude" in his shop (my words) We need to get his attention.


Edit: I reread your post about "no exhaust felt." Stay with that clue. If you look at the animations you will see the engine has to breathe.

motoman said:

Wilburn, I am certainly not an expert on 2 strokes and did talk partial trash about piston skirts. It's the piston crown which acts like the intake and exhaust valve. I have been on line and will offer the following that might help.

Compression is surprisingly high if a you tube is to be believed 190 PSI on a rebuild. Yikes.

My own Husky has a compression release which I use. It really makes a difference in starting. The web is full of examples of compression releases. If yours is too old to have one it may be you are feeling "normal" compression ? During a portion of the stroke both the cylinder head and the crankcase are under compression.

Transfer ports are part of the two stroke engine. In the really old days that's all there was. Reed valves are widely used now and sit in the intake runner back of the carb. But they apparently would not give your symptom.

Fish has apparently suggested some online refs. I will add "indianmcinfo.com" and "pilotfriend.com" for excellent cutaways and animation of the 2 stroke operation. Might help.

There is a forum member who said he was the "two-stroke dude" in his shop (my words) We need to get his attention.


Edit: I reread your post about "no exhaust felt." Stay with that clue. If you look at the animations you will see the engine has to breathe.

Click to expand...

Thanks motoman.. I think it was you who suggested I check out the forums on sawhawgz.com.. I registered for their forum but have not ads yet posted my situation on it