Questions about Husqvarna 51 chainsaw

[jeffbecky1]

Hello, I'm new to this forum and have a few questions about a Husqvarna 51 chainsaw that I got from a consignment store. They said it had compression and spark but could not get it going. I bought it for $20 and took it home. I tried to start it and could not get even a little cough from it. Took off muffler and saw a little scoring but not bad. Took off carburetor and cleaned it up. Took spark plug out and checked for spark. Has some spark but can't tell if it might be weak. What year was this saw made? Can anyone tell my by the serial number - 2170579?

I have good running 55 Rancher. Thinking of taking the ignition module off and trying it on the 51 to see if it will fire up. What do you all think?http://www.arboristsite.com/images/smilies/frown.gif

 

[HiOctane]

Check the compression first,exhaust dont tell everything even if you see a bit of scoring.If compression is good,drop few drop of gas under the plug.If she still dont start ,then ignition is bad.Your saw is '92.You can use the module from 55.

 

[jeffbecky1]

Compression was low, now what?

Compression was low, now what? New piston and rings? Where to buy good parts at a reasonable price?

 

[mattinky]

You need to tear it down and see how bad the damage is, if the cylinder is'nt too bad you can clean it up with muratic acid (do a search there's tons of info here on doing it) You can get an aftermarket piston & rings from Bailey's for a good price. But... first & foremost you need to find out why it siezed in the first place or you'll just fry your new piston. I would highly suggest you install new crank seals while you're at it

 

[cjcocn]

Compression was low, now what? New piston and rings? Where to buy good parts at a reasonable price?

That piston only uses one piston ring. Bailey's is a good source. If you do a search on piston rings you will find tons of info to walk you through it, plus a few more leads on where to buy rings.

If you buy your piston rings at Bailey's, they will send you 2 and you can keep one for a spare. Also, you should look at buying their piston ring compressor set - it is only about $4 and makes it very easy to install the rings.

Check your grommets between the carburetor and the cylinder. If they get too worn out then they do not seal properly. Check that they are still supple and not distorted.

.... Oh yeah, unless you have all required replacement parts and can do this job in one night, keep all of your bolts, screws, etc separate in little zip-lock bags and write down where they belong. I left mine sitting on my bench and for some stupid reason thought it would be a good idea to move the cloth that the parts were on "just a little bit." It was "fun" sorting everything out again.

 

[jeffbecky1]

Thanks for the info

Thanks for the info, I'll tear into it sometime this week.

 

[jeffbecky1]

Piston scored, cylinder not bad(I think)

Piston scored bad on exhaust side, cylinder doesn't look bad. Will have to try the acid thing after I find out how to do it. Found new 45mm piston on eBay for $20 + $6 shipping.

I was wondering about how much wear these cylinder get over the life of the saw and thought there might be some slop with the 45mm piston. Should I use a 46mm piston from a 55Rancher? Or is that going to be too tight?

Whatcha think?

 

[cjcocn]

Piston scored bad on exhaust side, cylinder doesn't look bad. Will have to try the acid thing after I find out how to do it. Found new 45mm piston on eBay for $20 + $6 shipping.

I was wondering about how much wear these cylinder get over the life of the saw and thought there might be some slop with the 45mm piston. Should I use a 46mm piston from a 55Rancher? Or is that going to be too tight?

Whatcha think?

If your cylinder is worn that bad then the nikasil coating may be compromised. Also, there is no guarantee that it wore perfectly round, or that it wore enough to fit a 55 piston in there.

Get a micrometer to check the cylinder to see if it is out of round. If it is, or if you cannot get the cylinder cleaned up, then you can consider throwing both a 55 piston and cylinder in. Otherwise, just go with a new piston, rings, etc.

FWIW, I just re-ringed a 51 from the early 90s and it worked out okay.

HTH