Is my Partner S50's engine seizing up?

[GGraziano]

I inherited a Partner S50 chainsaw from my father about 10 years ago. It has been a pretty reliable saw, but I may have cooked my own goose here. It has been sitting on a shelf unused for about 2 years. It started and ran fine then. I attempted to start it the other day (after fresh fuel mix, etc.) and could barely pull the starter rope. My first thought was partially seized engine, so I removed the spark plug and tried the rope again. The engine turns over effortlessly. I put some 2 cycle oil in the cylinder and worked it around, drained it, and left it overnight. Sadly, the same situation confronted me when I tried starting it the next day. The other puzzling thing is I removed the pull rope assembly to see if there might be a problem there, but it seems fine. I could turn the engine over by rotating the flywheel by hand, but when you put the whole mess back together you can barely pull the rope. Could there be some kind of compression release that has stopped working? I've never heard of such a thing on a chainsaw, but I've never owned a Swedish saw before this. Given today's labor rates in a shop, I'm wondering if it even makes sense to pay to have this diagnosed by a pro.... Can anyone offer insight into what might be ailing it?

 

[LonestarStihl]

I had some issues with a gas blower and my local Stihl shop only charged $20 to diagnose and if they did the work that 20 went towards the work as well. May be worth asking a few local shops what they would charge just to diagnose

 

[grizz55chev]

Pull the muffler and inspect the piston, cylinder condition. If this shows no problem, then you have a starter rope binding, maybe a split in the spool where the rope rides.

 

[GGraziano]

Ok, thanks. I'll see if I can see a problem with the piston as you suggest. Txtroop, I have a couple of good shops I'll ask about diagnosing the problem on Monday.

 

[SawTroll]

Sounds like something is up with the starter, that makes it bind when the plug is in place, creating compression?

It does not sound like the engine is seized, as I read the description - but of course it doesn't hurt to look....

 

[burnses]

if it turns over nice by the flywheel with the starter off then you might have a issue with the starter assembly. On some huskies the pulley that the rope winds onto cracks and the rope binds in the groove...makes the saw real difficult to pull over then the plug is in...if no luck I could ck it out for ya im in Harvard...good luck

 

[GGraziano]

if it turns over nice by the flywheel with the starter off then you might have a issue with the starter assembly. On some huskies the pulley that the rope winds onto cracks and the rope binds in the groove...makes the saw real difficult to pull over then the plug is in...if no luck I could ck it out for ya im in Harvard...good luck

I've got a couple of good suggestions to check on, which I will do this afternoon. What is puzzling me is that the pull rope assembly works smoothly and easily when disconnected. Also, I rotated the flywheel by hand with the pull rope assembly off and it feels like I would expect it to feel. Still, put it all together and you can't turn it over fast enough to start it. Anyway, I have my "marching orders" for the moment. Thanks!

 

[spudulike]

Sometimes the fuel dries out when an old saw is left on the shelf and leaves thick oil around the bore and this seals it up and gives a higher than normal compression. Other than this, the carb could have a leaking needle valve that has filled up your crankcase with fuel so worth pulling the plug, turn the saw upside down and pull it over fast and see what comes out. If this is all OK and the saw pulls over smooth on the starter handle with the plug removed then just man up and give it a big drop start and it should pop.

Had a long dialogue on a similar basis with a 064 owner that he couldn't pull over. It appears he just hadn't used a saw with no decomp and a lot of compression before!

 

[Ikeholt]

Since it turns over fine with the starter cover off, my first guess would be your starter cover is binding on the flywheel pawls. You need to slowly pull the rope as you put the cover in place. Work the rope back and forth to make sure it turns freely. Plenty of parts for those around.

 

[GGraziano]

So I checked some things, and here's what I found. I removed muffler to view piston and assure port was not blocked. What I could see of the piston and ring looked fine--like new, in fact. Port is clear, and compression is still too high with port wide open. I tried backing the pull rope assembly out a bit, in case it was binding against the flywheel pawls. It made no difference. I'm beginning to think that the old fuel/oil mix left in it too long, leaving a residue that is causing the compression to be too high is the most likely explanation. I'm thinking now might be a good time to own a compression gauge to prove/disprove the point. Assuming I can find one nearby that doesn't cost an arm and a leg, does anyone know what I should expect to see if it is normal?

 

[grizz55chev]

So I checked some things, and here's what I found. I removed muffler to view piston and assure port was not blocked. What I could see of the piston and ring looked fine--like new, in fact. Port is clear, and compression is still too high with port wide open. I tried backing the pull rope assembly out a bit, in case it was binding against the flywheel pawls. It made no difference. I'm beginning to think that the old fuel/oil mix left in it too long, leaving a residue that is causing the compression to be too high is the most likely explanation. I'm thinking now might be a good time to own a compression gauge to prove/disprove the point. Assuming I can find one nearby that doesn't cost an arm and a leg, does anyone know what I should expect to see if it is normal?

Pull the plug squirt some wd 40 in the hole, crank it over till dry, install the plug, run it.

 

[smokey7]

I thought I read that the op hadput someoil downthejug already.... Maybe its built up in the case?

 

[grizz55chev]

I thought I read that the op hadput someoil downthejug already.... Maybe its built up in the case?

That's why I suggest putting wd 40 in, might clean the oil out and still have enough lubrication to prevent a dry cylinder, and wd40 will make it smoke briefly but it'll fire and not foul the plug.

 

[Justsaws]

Flip the saw around so that any liquid in the crankcase can drain out the exhaust port or pull the spark plug and let it drain out the hole. Might have an excess of fuel/oil in crankcase, everything will work fine slowly put becomes very hard to pull over quickly. Old carb kits and large temp changes will allow this to happen. Let it sit and drain for a bit, you can pull over the saw with the plug removed but make sure it is switch off and that the plug wire can not ark a spark and ignite the fumes shooting out of the hole.

 

[GGraziano]

I think I'm getting there. I just had it running for about 3 seconds. Compression tested 105-110 psi, so I threw the darned thing back together and tried it. I only got a pop at first, then nothing. So I tried a little snort of starting fluid in the cylinder head. It still pulls hard, but it will turn over enough to spark and ignite. Now I have to see if I need to remove and clean the carb if it appears it isn't gettiing consistent fuel supply. I suppose the same old fuel crapping up the engine could affect the carb, too. I've got to give my arm and shoulder a rest before cranking that beast again, though. A good time to try draining and drying out. Thanks again!

 

[grizz55chev]

110 psi low side of where a saw will run. Probably needs rings.

 

[GGraziano]

Hi again. Been trying to get over a cold while waiting for a carburetor rebuild kit to arrive. Enough folks suggested crap in the carburetor to convince me a rebuild wouldn't hurt. Determining what carb was in it turned into a real Easter egg hunt! I finally identified it as a Walbro, and the construction of it didn't look too intimidating. There were all the usual frustrations with a first-timer trying this. The throttle linkage proved to be the peskiest item, falling off the trigger every time you disconnect from the carb. (Frankly, I still could not tell you how I got it reattached in an area impossible to see.) I noticed, in the course of doing all this, that the fuel line was badly split where it connects to the carb. The other weird thing to my limited mind is the other end, where it goes into the tank, appeared to just be forced into a plain hole in the top of the tank. The more I thought about this the more I wonder if this is the problem: shouldn't the fuel line go all the way to the bottom of the tank? Has a piece of line and a connector maybe fallen into the tank? I don't see how this beast could get any fuel absent that. Am I making sense?

 

[Jeff Lary]

Hi
I could be way off but I think your problem is low compression.

 

[GGraziano]

My father was a mechanic all his working life. I inherited virtually none of his abilities. I don't believe I ever heard him swear at a car or small engine. I, on the other hand, shed blood and utter much profanity to effect even the most basic mechanical work. While trying to resurrect his Partner S50 saw, I could picture him shaking his head and saying: "Gary, if you're working flat rate you'd starve." Maybe so, but I freakin' fixed it! I just came in from starting and running it for short interval. It ended up needing a new fuel line and filter. I found the petrified remains of the old one inside the tank. The only remaining issue, which I will address before attempting to cut with it, is the throttle linkage is binding a bit, making the trigger stick. There's no way to know, but it might not have even needed the carburetor rebuild. As long as it worked, I'm happy. Thank goodness for the Internet. I would not have attempted it without it.

 

[Jeff Lary]

glad that is all it was good on you .