Need help with chain saw

[exbass94]

I have an old (mid-late 80s) Husqvarna model 50. When it actually starts, it runs great. The hard part is getting it started. Most of the time, when you pull the cord, it will only move an inch or two and violently snap back into the saw, ripping it out of your hand. The engine is not seized, as I said, it runs absolutely perfectly.
If I remove the spark plug, I can turn the engine over with the cord a hundred times and it will never snap back. As soon as I put the spark plug back in and the engine has compression again, it starts snapping back again.
Lately it's been one problem after another with this thing, but I suppose that's to be expected when using a saw that's older than I am.

 

[Shran]

Make sure the clutch is in good shape as well as the pull starter assembly.

 

[Earl43P]

Make sure the spark plug isn't just a bit too long.
Crank it over as you approach fully seated, see if it's hitting.
BTDT, try a shorter plug.

 

[chandymanusa]

If its hard to start pull muffler and check for carbon build up in exhaust port this is a problematic spot for 2 cycle engine and check muffler for being plugged up some critters like to build nest in them

 

[exbass94]

The spark plug is fine, it's the same plug that's been there for years (new plug but same part number) and it runs fantastic when it actually starts. I just rebuilt the whole starter assembly, including rewinding the recoil spring what a PITA that was. This problem has been going on before that though, it would usually start after a few tries, but yesterday it just wasn't happening.
I'm gonna remove the muffler and check for carbon next and see where that gets me.

 

[exbass94]

So, I finally got around to working on this thing the other day. I found that pouring Seafoam into the cylinder and letting it sit overnight does nothing to clear up carbon. I ended up pulling the whole cylinder off and scrubbing it out with carb cleaner and a toothbrush. I also cleaned off the top of the piston. It's clean as a whistle now, I just need to put it all back together and see if it works.

I can't put it back together until I get a new gasket though. The dealer is closed for the holiday and I may not have time to go there till Friday. I'll try to get there sooner. If this doesn't work, then I am officially out of ideas and out of patience, and the first person with $20 gets a nice used chainsaw.

 

[Downey]

if you get rid of it make sure you buy a stihl

 

[Will]

I have an old (mid-late 80s) Husqvarna model 50. When it actually starts, it runs great. The hard part is getting it started. Most of the time, when you pull the cord, it will only move an inch or two and violently snap back into the saw, ripping it out of your hand.

Sounds like it may have an automatic decompression valve. If it does, you pull the rope slowly until you feel resistance and then stop and let the rope back in. Then you pull hard. I have a big motor like this and before I learned about automatic decompression valves I had the handle break in my hand. That hurts.

And use starting fluid. I use it on my old Echo trimmer which won't start without it, but runs like a deere with it. I also use it on my Yamaha generator because I use it so rarely the fuel system is always dry.

 

[exbass94]

UPDATE if anyone cares: Finally got the new gaskets and put it back together the other day. I reinstall the spark plug, yank the cord and.....it turned over without trying to break my hand off!! After a couple more pulls and some starting fluid, it fired right up.

I tried to cut down some tall stumps, but the chain is as dull as a butterknife. So, now I gotta attempt to sharpen it, or just get a new chain. This thing sure is a project, but a really good learning experience. I'm getting to be a pretty good small engine mechanic.