Chainsaw problem

[Bruce King]

21 yr old Husqavarna 51 has been sitting around most of the time for 6 years. The pull cord assembly is good but takes a tremendous amount of effort to pull it 6 inches. It’s not the safety arm or the clutch. With the plug removed it’s smooth and easy. Has about 1/64 buildup on top of the piston. Internet sources say it’s very common but no one ever claims to have ever truly fixed this particular problem. I think the engine needs to come apart for cleaning and inspection. Anyone fixed one like this, very high compression?

[Izzy Camire]

Bruce, I have a 51 which I use when needed. The first couple pulls on the cord are like you describe I can only get a few inches. I keep at it and a couple of pulls later it is ok and it starts right up. The compression on them gets your attention. You may want to keep pulling and get it to start and perhaps it will clear itself up.

[Doug Dawson]

Bruce, I have a 51 which I use when needed. The first couple pulls on the cord are like you describe I can only get a few inches. I keep at it and a couple of pulls later it is ok and it starts right up. The compression on them gets your attention. You may want to keep pulling and get it to start and perhaps it will clear itself up.
If you keep it just inside the front door, and test it periodically just like a smoke detector or a GFCI (test monthly), it pulls easier.

[Bruce Wrenn]

Don't they have a compression release? My 50+ year old Roper (Craftsman) has one. Could be compression release valve is stuck from lack of use.

[Bruce Wrenn]

If you keep it just inside the front door, and test it periodically just like a smoke detector (test monthly), it pulls easier.Crank it inside and get two tests for the price of one, smoke detector and chainsaw. .

[Bruce King]

It used to get a little hard to pull but now the rope will break if I pull any harder. Saw a video on rebuilding a 55 which has a compression release but so far I don’t see one on the 51.

[Tom M King]

Ask in the Chainsaw forum, on the Forestryforum. Someone there will know about that specific saw.

[Bruce King]

Ask in the Chainsaw forum, on the Forestryforum. Someone there will know about that specific saw.
I was on there, that’s where I found this to be a common problem with many saws. Some fixes are on there but no help for mine. I’m taking the piston out this afternoon to look.

[Bruce Wrenn]

Could be a carbon build up, raising compression. PB Blaster makes a carbon desolving spray for small engines.

[Bruce King]

Plenty of carbon and something on the piston side. No scoring evident. After all this work I’ll be installing new parts. Having trouble with the ads though. Picture of whole top end kit with a part number of the cylinder is common. Mine is a 44mm and most kits are 45 or 46mm and they say they will work. Anyone upsized a cylinder on a chainsaw?

[Bruce Wrenn]

Parts list shows a decompression vavle

[Bruce King]

The 55 uses the same documentation as the 51 with notations on differences. 51 epa does not have one.

[Ronald Blue]

If I am reading your comments correctly your cylinder bore is 44 mm? Unless you are installing a matching piston you wouldn't want that sort of clearance. That would be a recipe for disaster. I'm probably misinterpreting what you are referencing.

I looked up the specs and it listed it having a 45 mm bore.

[lowell holmes]

https://www.lowes.com/search?searchTerm=kobalt%2080v%20chainsaw

Check this site, I have one and it is good.

[lowell holmes]

Check this site, I have one and it is good.

https://www.lowes.com/search?searchTerm=kobalt%2080v%20chainsaw

[Bruce King]

Here is the kit I ordered, it’s 45mm but designed to fit the 51 epa too.
I can install a compression release on this one.
https://www.hlsproparts.com/product-p/503609171.htm

[Bruce King]

Check this site, I have one and it is good.

https://www.lowes.com/search?searchTerm=kobalt%2080v%20chainsaw

I have the 80v kobalt lawnmower so I would consider getting that one too but need a lot of power for clearing after hurricanes.
I was about to cut down a Chinese Tallow tree due to all the greasy stuff that falls off it and onto my driveway when I found this one inoperable.

[Ronald Blue]

I went with the Ryobi 40 volt because I had the string trimmer. I've been quite happy with it. Surprising battery life and power. The nice thing is it doesn't matter if I use it twice a week or once every two years there aren't any gas issues from sitting unused. Oh the other big plus....is it's quiet. Only the whirr of the motor and chain. When I burnt wood for heat a gas saw was a no brainer. I get that you like/need to have a saw that performs when you have a hurricane clean up. Good that you have the skills to do this rebuild. Good luck on it.

[Bruce King]

Finally got the rest of the parts and got it running today.
What I learned was that the smaller saws are harder to pull since they don’t have a decompression valve. Add in some carbon buildup and the cord might break before a really strong person could pull it. I put in a larger cylinder/piston that accepts a decompression valve. It lasted 20 years with heavy use the first few years. Only buy one that has a decompression valve is my advice. They are self closing once the saw starts running.

[Bruce Wrenn]

My Roper (Sears) from 1973 has compression release. Otherwise there is no way I could crank it when I bought it fifty years ago, much less today.

[Tom M King]

My hotrod 066 had an aftermarket larger cylinder put on it, and it doesn't have a compression release. I put toes of my right foot in the back handle, and the left foot has to hold it down on top of the loop handle.

[Tom Bender]

Sounds like the piston is getting gunked up.