McCulloch Chain Saws

Rugged made
shop deals on amazon
Treestuff
Shop deals on ebay
Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
You will need to tare it down far enough to see the outside top of the cylinder. It will have a A, B or C stamped on it. You will match the piston up with that or if you have to have the cylinder replated then it won't matter they will fit the bore to the piston. By the way the A B or C is the size of the cylinder. It is very little but enough that it needs to be followed.

Brian
 
You saw has what is called Q porting. Looking into the exhaust port you see where the top of the port makes a upward peak. That is to let some compression off, enough to let it start easier. My self I prefer a compression release and have thought about putting one on my PM800. The Q port is in my opinion not enough to make an easy start.

Brian
 
Rob, usually the cylinder is stamped near the spark plug hole. If there is no marking then consider it a "B".

Brian, have you seen a squared off Qport like Rob's. I don't think I have.

Ron
 
There should be a stamp on top of the cylinder indicating "A", "B", or "C". The "B" piston (92519) is readily available from cheapchainsawparts for $50, others come up from time to time typically from $69 to $99..."A" is 92518 and "C" is 92520.

There are no real tricks to disassembly of the 10 Series saws, just remember there are 8 screws holding the crankcase halves together, 4 internal (12-24 screws) and 4 external (8-32 screws). Remove the two screws that hold the clamp for the boot before you take the tank off the body of the saw, there is one screw in the oil tank that holds the front anti-vibe mount.

The 82 cc saws are thin ring except for a few early SP80 models, there are rings in there but they are stuck in the grooves.

Mark
 
Thanks guys. Went out tonight and pulled it pretty much all apart. Probably the only thing left is to clean it well and then pull the case halves apart. It was fairly straightforward except for: 1) getting the rear rubber isolators out from under the choke linkage and oiler linkage; 2) realizing that the carb-to-cylinder boot had screws under the carb; and 3) pulling the hose off that goes from carb area to crankcase. The latter wasn't actually hard, but I kept looking for a clip to release. Turns out it is just a wire ring crimped on or something.

Mine is a 'B' cylinder head, luckily, so that should be good for getting a piston, assuming the head is salvageable. Even found on on eBay for under $40. Not bad. Comes with rings and wrist pin (?) too. Does the "1186" engraved on the head mean it was made in 11/1986?

20170918_204612-L.jpg

20170918_200117-L.jpg


Thanks,
Rob
 
Will I have to pull the flywheel and clutch off in order to keep disassembling? The flywheel doesn't worry me too much but I thought I read that putting the clutch back on requires special tools?

Rob
 
No special tools to put on but may require a puller to get the clutch and flywheel off. Loosen the nut on each until the nut os level with the end of the shaft, pick it up by either clutch or flywheel which ever one that you are trying to get off and rapp the nut with a hammer and usually they will letgo. It is better to have them off. While rebuilding the saw you will want to replace the crank seals.

Brian
 
Rob, should be wrist bearings with piston. Doubtful that a pin is included.

What does the cylinder look like inside? I am really curious about what appears to be a square top of the Qport.

Ron
 
rwoods said:
Rob, should be wrist bearings with piston. Doubtful that a pin is included.

What does the cylinder look like inside? I am really curious about what appears to be a square top of the Qport.

Ron
Click to expand...

I think it was a 'piston pin' that is included. A small cylinder thing.

I haven't pulled the case apart today. Had to deal with other stuff instead. Maybe tomorrow. What does a 'normal' Qport look like?

Thanks,
Rob
 
May just be the camera angle or some transfer or possibly a variance in casting that resulted in a slightly higher exhaust port. All I have seen before yours and Mark's have rounded tops. I believe the little ridge is where the outside and inside molds meet. The outside has a squared off slot that meets a rounded inside top. Possibly your's was cast with the inside mold elevated slightly. Whatever it is it matches with the melt pattern on the piston. Below to illustrate what I am talking about are photos of an NOS cylinder.

As an aside, did you notice that it appears MAC marked your cylinder as an A and then changed it to a B.

Ron

IMG_2524.JPG IMG_2527.JPG
 
rwoods said:
May just be the camera angle or some transfer or possibly a variance in casting that resulted in a slightly higher exhaust port. All I have seen before yours and Mark's have rounded tops. I believe the little ridge is where the outside and inside molds meet. The outside has a squared off slot that meets a rounded inside top. Possibly your's was cast with the inside mold elevated slightly. Whatever it is it matches with the melt pattern on the piston. Below to illustrate what I am talking about are photos of an NOS cylinder.

As an aside, did you notice that it appears MAC marked your cylinder as an A and then changed it to a B.

Ron

View attachment 602626 View attachment 602627
Click to expand...

Interesting info. To my untrained eye I don't see much difference between your pics and mine. Are you talking about the tip of the 'V' or the other side?

As for the piston, you think that is from heat/melting? To me it looks like something got into the cylinder and scraped/gouged the piston. But I am a total newbie when it comes to engine problems.

And yes, I did notice the "A" crossed out and changed to "B". Is that because they measured it and found that it was different than originally intended?

Rob
 
Sorry for the one upside down picture. I was talking about the tip of the V - yours looks to be square where mine is round. Yes, I think your piston is melted. Look at the streaks to the side of the gouged out area. It may have also ingested a needle bearing or something else. You can tell better once you crack it open.

Ron
 

Similar threads

C
Want to Buy McCulloch Super 250
Replies
6
Views
740
Bill G
B
Chainsaw Collectors
McCulloch 610 chain brake guard install, help?
2
Replies
20
Views
1K
singinwoodwackr
singinwoodwackr
B
New from Bavaria
Replies
5
Views
409
Syncop8r
Syncop8r
J
A few very nice old saws
Replies
0
Views
352
jackdaripper
J
L
McCulloch Mini Mac 35
Replies
1
Views
292
gumneck
gumneck

Latest posts

Back
Top