SP81 Cylinder and Piston. Smoked?

[davidtown]

I recently purchased this SP81 from my neighbor at his garage sale. Paid $100. It ran. Pretty much full of old dust and chips so I pulled things apart to clean it and then looked inside the cylinder. What I saw was some scoring so I finished taking it apart.

My gut is saying that it is toast but wanted to check here first. Pictures are attached.

If it is toast is there anything that I can do to clean it up? Guessing No...
What parts transfer over to the SP81 from other saws? I'd like to get this to be a reliable saw. Yes, I could put it back together as is and run it till she completely craps out but that will delay the inevitable.

Be well,
Dave

 

[Chainsaw Jim]

I'd say your gut feeling is dead on. The cylinder can be re-plated by U.S. Chrome for around $250. If the rest of the saw is nice enough it can be worth doing.

 

[s sidewall]

Is that transfer or gouged?

Steve

 

[grizz55chev]

Is that transfer or gouged?

Steve

Looks like the plating is gone.

 

[davidtown]

Gouged. Unfortunately.

So, my only option is replating? Do I need to purchase a piston and send it with the cylinder when replating? New to the replating thing.

Thanks,
Dave

 

[s sidewall]

If it's deep, doubt plating will help.

Steve

 

[Chainsaw Jim]

U.S. chrome can also fix damaged cylinders. They do prefer sending a nos position along for accuracy.

 

[davidtown]

Thanks Jim.

 

[smokey7]

I think pistons are very hard to find. Personally i wouldnt put the 300 into that saw plus the 100 you bought it for basically a 150 doller saw to me. Id smooth the scuffs on the piston clean up the jug as good as i could maybe new rings and run it as a backup saw at like 20.1 mix. I just cant put good money after bad on a low value outdated saw.

 

[rwoods]

Piston looks pretty good to me. Bet it is a replacement. The cylinder looks to have a lot of transfer. I suggest you hit the cylinder with the acid-less flapping sandpaper method described and promoted somewhere on this forum. You might find it is all transfer and not gouges. Do not use acid, if you have a gouge or any missing plating you can destroy that cylinder quick.

Pistons can still be had with price depending on whether you have an A, B or C cylinder and NOS or aftermarket piston. I think you piston looks fine compared to a lot you find in these old saws. SP 81 are highly desirable saws. Ron

 

[DND 9000]

Parts availibility shouldn`t be a problem. The SP 81 is series 4231 but uses the well known 4137 series engine of the trimmers FS 80, 85 and others.

 

[rwoods]

Parts availibility shouldn`t be a problem. The SP 81 is series 4231 but uses the well known 4137 series engine of the trimmers FS 80, 85 and others.

Don’t believe a McCulloch SP81 chainsaw shares parts with a Stihl trimmer.

Ron

 

[CR888]

Don’t believe a McCulloch SP81 chainsaw shares parts with a Stihl trimmer.

Ron

The FS80 trimmer would go pretty hard with an 80cc Mac piston in it .....gotta get muhself one of dose!

 

[DND 9000]

Ok my bad, I`m sorry I didn`t had a closer look I`m sorry. did I think about?

 

[grizz55chev]

Ok my bad, I`m sorry I didn`t had a closer look I`m sorry. did I think about?

Lol!

 

[Chainsaw Jim]

I think pistons are very hard to find. Personally i wouldnt put the 300 into that saw plus the 100 you bought it for basically a 150 doller saw to me. Id smooth the scuffs on the piston clean up the jug as good as i could maybe new rings and run it as a backup saw at like 20.1 mix. I just cant put good money after bad on a low value outdated saw.

A properly restored sp81 will easily fetch $600.

 

[s sidewall]

Ok my bad, I`m sorry I didn`t had a closer look I`m sorry. did I think about?

We all get brain farts occasionally.

Steve

 

[rupedoggy]

A properly restored sp81 will easily fetch $600.

I knew I heard that cannabis was in wide use in Oregon.

 

[RandyMac]

Always has been.

 

[Cowdudy]

Parts would recover the 100 you have in it pretty quick. But,I just happen to have a sp81. It has started every time I decide to run it, and it’s in decent shape maybe could use some cleaning. . Not really sure it came with one but it doesn’t have a hand guard on it. I’m really not attached to it. If your interested I could post some pictures tomorrow.


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