McCulloch Chain Saws

[leeha]

Fantastic score you got struggle.
The 660 is a nice saw and the 3100
is a great saw as well.
Congrats


Lee

 

[heimannm]

660 vs. Super 250 - I looked at the IPL's a while back and they show different part numbers, with McCulloch who really knows?

Struggle, very nice indeed. You will be suprised how much pull is in that 660 when you drop it in a log...be sure to hold on or it will take you for a ride.

Mark

 

[cpr]

SK has a very interesting saw on "that place". Never seen a 740 with decomp before. More Franken-McCulloch...

 

[rwoods]

SK has a very interesting saw on "that place". Never seen a 740 with decomp before. More Franken-McCulloch...

I haven't either so I looked it up last night - Model Profile: 740 - shows one in the drawing but I think that is actually a 795 shown if I made out the lid correctly. Ron

 

[cpr]

SP125 came today. Looks very clean, bore and piston look good, but compression is only 95psi. Not complaining, just trying to figure it out.

1. Could the piston be hitting the schrader valve on my tester at TDC and not giving a true reading?

2. Decomp replaced with a bolt. Leak source?

3. Popsicle stick bore check seems to indicate stock bore and it is an unpainted, unnumbered block which I would guess is a replacement and would not have been bored. But if it indeed had been and reassembled with the wrong piston... I hope this isn't the case. This new job doesn't give me time to be tearing into a saw at that level.

Anyway, what do you guys think? I don't want to start it until I figure this out.

 

[stinkbait]

SP125 came today. Looks very clean, bore and piston look good, but compression is only 95psi. Not complaining, just trying to figure it out.

1. Could the piston be hitting the schrader valve on my tester at TDC and not giving a true reading?

2. Decomp replaced with a bolt. Leak source?

3. Popsicle stick bore check seems to indicate stock bore and it is an unpainted, unnumbered block which I would guess is a replacement and would not have been bored. But if it indeed had been and reassembled with the wrong piston... I hope this isn't the case. This new job doesn't give me time to be tearing into a saw at that level.

Anyway, what do you guys think? I don't want to start it until I figure this out.

Something is not right with the decomp or your pessure tester. My 125 has the original cylinder and it is unpainted, so that doesn't mean anything.

 

[Brian13]

Does the cylinder look like it was freshly honed. Maybe the rings are wore out, and it just needs a re-ring.

 

[cpr]

No discernable honing marks. It is very clean inside, zero carbon as if this was a very recent rebuild. Could be the rings... That would suck. No time...

 

[Brian13]

Do the SP125s have pinned pistons or are the rings free floating. Can you maneuver a ring end to see the gap.

 

[cpr]

floating. I'll check that out later.

 

[leeha]

SP125 came today. Looks very clean, bore and piston look good, but compression is only 95psi. Not complaining, just trying to figure it out.

1. Could the piston be hitting the schrader valve on my tester at TDC and not giving a true reading?

2. Decomp replaced with a bolt. Leak source?

3. Popsicle stick bore check seems to indicate stock bore and it is an unpainted, unnumbered block which I would guess is a replacement and would not have been bored. But if it indeed had been and reassembled with the wrong piston... I hope this isn't the case. This new job doesn't give me time to be tearing into a saw at that level.

Anyway, what do you guys think? I don't want to start it until I figure this out.

How doe's the piston, cylinder look through the exhaust port.
I have seen many sp125's with unpainted blocks. It could very
well be original. The rings could be stuck in the piston grooves,
or just plain ole wore out.
I would say you will most likely be taking it appart.


Lee

 

[cpr]

Pics...

 

[rwoods]

Didn't the seller list this saw "Runs Great with lots of NEW!! including the tank, panal and much more"? I took it that he had rebuilt the saw at least in part. Ron

 

[Brian13]

 

[cpr]

Thanks Brian, how DO you do that?

Yeah that's the way it was listed alright.

I checked around a little more. Piston has a slight dent on the crown over between ports. I've seen much worse on here, I don't think that's the problem. The piston will rock quite a bit on the pin when you roll it slowly through compression. No satisfying little chuff when it breaks over tdc. Not sure the piston should move that much on the pin center line when I poke it with a popsicle stick through the plug hole.

Anyway, I'm done looking at it. I'm not going within a foot of it until I hear back from the seller. I'm keeping it, but it's not worth what I paid like this.

Guess I'll just be quiet about it for now until this is over...

 

[cpr]

BTW, I believe I was wrong about the rings. They appear to be pinned and move freely within their limits, so that's not it, nor is it the plugged decomp. It's leaking past the rings.

Now I'll shut up. :mad-tongue:

 

[Brian13]

That sucks I hope you can get the seller to work with you. I will send you a pm about pics so not to clutter the thread.

 

[stinkbait]

I don't believe that is a 125 engine. I don't think that the 125 engines have the divider in the exhaust port. Mine has the 0val shaped exhaust port.

 

[Busmech]

125

I may be wrong but I've never seen a 125 with a bridged exhaust but then I've never seen a CP opened up. All of the SPs Cs that I have have a more oval port with no bridge.

I type too slow

 

[cpr]

Yep, I think you're right.