gene
ArboristSite Lurker
Hi All, I have an old SP81 that my father bought new in the 70's and that I use from time to time on larger live oak.
The saw recently had a problem crop up in that it wouldn't stay running at idle and high speed power was down a lot, finally the saw quit and wouldn't re start.
Spark was fine, changed plug and condensor also. Spark still fine.
I haven't had to adjust the carb for several years since I rebuilt it last time (Walbro SDC). It seems fine. I tried running the needle in (1 only, high speed) and then back out to the previous setting to clean any junk out. No help. (I have a new fuel line in the saw)
Pulled gas tank/carb mount, cleaned and resealed carb to cylinder boot and installed a new crankcase pressure line and gaskets.
Still it won't start for anything.
I checked compression pressure with a good gauge and am seeing 25psi w/o oil and 30-35psi with WD40 sprayed into the cylinder. My Husq 42 pulled about 50psi no oil. (Yes, I had the throttles wide open when doing this).
Now, in the past when trying to start the SP81, if I didn't have the compression release in, a jerk on the starter rope would almost not turn the saw over, now it turns over pretty easy with, or without the compression release.
There dosen't seem to be any noise around the compression release when it is closed, just when open.
Do I have some broken rings?
Would the fact that the saw hasn't run in a couple of weeks make the compression pressure that it develops a lot lower than normal without anything being broken?
Is this thing worth fixing due to the wonderful avaliability of parts at every convenience store?
thanks in advance...
The saw recently had a problem crop up in that it wouldn't stay running at idle and high speed power was down a lot, finally the saw quit and wouldn't re start.
Spark was fine, changed plug and condensor also. Spark still fine.
I haven't had to adjust the carb for several years since I rebuilt it last time (Walbro SDC). It seems fine. I tried running the needle in (1 only, high speed) and then back out to the previous setting to clean any junk out. No help. (I have a new fuel line in the saw)
Pulled gas tank/carb mount, cleaned and resealed carb to cylinder boot and installed a new crankcase pressure line and gaskets.
Still it won't start for anything.
I checked compression pressure with a good gauge and am seeing 25psi w/o oil and 30-35psi with WD40 sprayed into the cylinder. My Husq 42 pulled about 50psi no oil. (Yes, I had the throttles wide open when doing this).
Now, in the past when trying to start the SP81, if I didn't have the compression release in, a jerk on the starter rope would almost not turn the saw over, now it turns over pretty easy with, or without the compression release.
There dosen't seem to be any noise around the compression release when it is closed, just when open.
Do I have some broken rings?
Would the fact that the saw hasn't run in a couple of weeks make the compression pressure that it develops a lot lower than normal without anything being broken?
Is this thing worth fixing due to the wonderful avaliability of parts at every convenience store?
thanks in advance...
