Old Poulan 25....

mrcaptainbob · October 06, 2017, 09:34:32 PM

It's a running saw I just acquired. The only issue with it is fuel spurts back through the carb. What would cause that?

dougand3 · October 06, 2017, 11:24:16 PM

Exhaust port clogged with carbon. Reed valve not seating properly.

mrcaptainbob · October 07, 2017, 02:32:24 PM

Thanks, Doug. I'll check both today....

Al_Smith · October 08, 2017, 07:46:32 PM

Are you talking about an s-25? If so I never saw one that didn't spit fuel .

mrcaptainbob · October 08, 2017, 09:49:26 PM

Side decal has Micro XXV on it. Beneath that it's in English.

Al_Smith · October 09, 2017, 03:59:40 PM

It could be any where from 2 to 2.3 cubic inch and will have single reed valve .I think it's just the nature of them to spit fuel .
The 2.3 cubic inch saws,s-25 da and others were a long life saw ,often used as pro tree trimmers choice over others until better models came out .The ones with a points ignition could go forever ,the recommended fuel /oil ratio was 32 to 1 if that means anything . ;D

mrcaptainbob · October 09, 2017, 09:43:32 PM

Spits fuel. Well, then okay. Since it's in the carb I guess it'll get re-sucked back in. As for that mix ratio, yes, I did see that on the decal. I have read that it's the same as today's 40:1 oil mix. I don't really care, as adding a separate smallish fuel can to the stash is no big deal. But if I can use it, I would. Just don't want to burn up an otherwise good little unit. Thanks for the help.

Al_Smith · October 10, 2017, 06:09:53 AM

I've got three of that model that run and one that gave me fits .That one had been ran without the sponge air filter and sucked some kind of seed into it and lodged under the reed valve .It doesn't seal correctly and it ignited on me several times .I'm done with that one .

As for a new reed I have no idea other than flea bay where a person would ever find one .

Al_Smith · October 10, 2017, 06:22:22 AM

This model and variations were made for years .The best are the all metal models .Some had just a stub exhaust,some an aluminum muffler and most later ones a steel muffler .It came in every color of the rain bow with the secondary models sold under a different name with a different color selling cheaper than a lime green Poulan branded .Later models offered an anti vibration model .
Properly tuned they will rev out at around 10-11 thousand RPM .This little gem was the first saw I ever owned and it still runs like a top from circa around 1974 .I cut a lot of firewood with at one time when I sold the stuff .I didn't rebuild the carb until after 30 some years ,one fuel line .
I actually dropped a 30" maple with a 14" bar .That's trick believe me . ;D

dougand3 · October 10, 2017, 10:32:44 PM

Here is an S25CVA disassembled (similar saw). See how flat the reed is.... If yours bows upward (downward in real life cuz carb housing is upside down) - could cause the spitting. Like Al says, they do tend to spit even when perfect. And if reed is angled down, you can flip over and that can seat it better.