McCulloch Chain Saws

[PogoInTheWoods]

Good info, but that's for a hi and lo adjustable sdc.

It was simply intended to show you the order of the diaphragms which are the same for the fixed jet version.

​

1 turn out on a fixed jet is also usually a good starting point for the low circuit. Between that and the idle screw you should be able to obtain something to work with.

Well think I'm definitely leaning towards air leak on the sp81.

Tear it down and find out. Could be as simple as loose intake components or as involved as a leaky seal. Won't know till you investigate all the possibilities -- which should include testing the integrity of the short block itself by a vac/pressure test. If you're real serious, invest in a MityVac 8500 pressure/vac tester. $55 if you shop around. And don't rely soley on a pressure test when chasing a leak..., especially when you suspect seals. Pressure can often close a vac leak at a seal.

 

[Maintenance supervisor]

Well think I'm definitely leaning towards air leak on the sp81. I went through the stock fixed jet carb last night. It is spotless with good diaphragm and gaskets. Fuel line and filter are perfect. The tan check diaphragm was out of order, I fixed that. Adjusted needle arm.

Just ran saw and it doesn't idle well. You try to bring idle up and it just keeps wanting to climb. I started with lo jet 1.5 turns out. Turned it in a bit, no change. Started turning it out...2.0, 2.5, 3.0 turns out....revs just kept climbing. My guess is if it'll keep taking fuel like that then it's pulling in air.

Unless someone tells me otherwise not sure it's even worth trying points and condenser on this saw? I'm thinking carb boot under tank or crank seals are no good.

Yeah , when I've had check valve problems the saw will idle nicely but lean die on wot .
Usually I will get the saw to idle with a full tank of gas and tip it to either side and a leaking seal will pretty quickly reveal itself.

 

[PogoInTheWoods]

SP81 IPL...

 

[mogulmasher]

It was simply intended to show you the order of the diaphragms which are the same for the fixed jet version.

View attachment 756927​

1 turn out on a fixed jet is also usually a good starting point for the low circuit. Between that and the idle screw you should be able to obtain something to work with.



Tear it down and find out. Could be as simple as loose intake components or as involved as a leaky seal. Won't know till you investigate all the possibilities -- which should include testing the integrity of the short block itself by a vac/pressure test. If you're real serious, invest in a MityVac 8500 pressure/vac tester. $55 if you shop around. And don't rely soley on a pressure test when chasing a leak..., especially when you suspect seals. Pressure can often close a vac leak at a seal.

My comment was mostly in reference to a starting point for setting low jet. Thanks!

Yes, I think it's time to get deeper into this saw. Sadly I purchased it with the understanding it was a very low use saw. Supposedly was a 2 owner saw and original owner didn't use it much. Well bottom plate is welded, paint is more worn than pics show, obviously ignition has been changed, etc. so it's had a life typical of this type of saw. Which is fine, just wish I knew what I was getting into.

 

[PogoInTheWoods]

SP81E...

 

[mogulmasher]

Yeah , when I've had check valve problems the saw will idle nicely but lean die on wot .
Usually I will get the saw to idle with a full tank of gas and tip it to either side and a leaking seal will pretty quickly reveal itself.

Already replaced tank valve. Saw won't idle for crap, but actually runs up pretty strong. Unfortunately it ain't all there though cause my pm700 would outrun it.

I tipped saw side to side today. It had no change with flywheel side up and stalled with clutch side up.

 

[mogulmasher]

Poge, thanks for the IPL.

 

[PogoInTheWoods]

My pleasure. Tearin' one down isn't as bad as it looks and you should receive plenty of help here when you decide to dive into it.

 

[Maintenance supervisor]

Already replaced tank valve. Saw won't idle for crap, but actually runs up pretty strong. Unfortunately it ain't all there though cause my pm700 would outrun it.

I tipped saw side to side today. It had no change with flywheel side up and stalled with clutch side up.

Yup seal, at least you've got lots of information on this sight.
Out of curiosity is it an EBay saw?

 

[PogoInTheWoods]

You obviously don't need to tear it all the way down to do seals but I'd also be curious about how well the short block is sealed if I were you. Someone could have been in there and just bolted it back together without re-sealing. Be nice to know how the bearings are as well.

 

[mogulmasher]

Yup seal, at least you've got lots of information on this sight.
Out of curiosity is it an EBay saw?

Nope, got it from a member on here. I'm still satisfied to have the saw despite it's condition not accurately being described.

 

[Maintenance supervisor]

Nope, got it from a member on here. I'm still satisfied to have the saw despite it's condition not accurately being described.

For the right price I've been happy with some beat saws.

 

[mogulmasher]

Paid a touch more than I should have, but not too much. So I'm good. Anyways, I shelfed it for a bit, gotta get back to my Mac 790.

 

[Marine-piper]

McCulloch Super 44a had a gunked up piston, it finally came out a week later.
I honed the cylinder and cleaning up the piston now, going to get new Caber rings.
I'm looking for a case cover for the saw due to corrosion if anyone has one I'll buy or trade something that I have.

Homelite collector in training [emoji879]

 

[iwannachopwood]

Not to high jack any body but what’s this I found in the latest dead saw haul
38L C5956
440

Those are the numbers on the bottom here’s a pic! I’m trying I’m searching, winner that id’s this saw wins pics below thanks



View attachment 757024 View attachment 757023

 

[ThistleIA]

Don't see any pics but the 440 on the bottom of crankcase indicate its model number

Here's mine

 

[BigBlue]

This past weekend I tore down a nice Super Pro 81 that I got a while back. I knew the engine was toast from the lack of compression. As expected, I found the piston eaten up pretty bad on the exhaust side. I assume damage happens on the exhaust side because something enters the engine and falls to the bottom, right? Not from something entering the exhaust port? Anyway, the cylinder is scratched up a bit and won't be usable as is. It's not big gouges or anything, but I can feel it with my fingernail. If I had the cylinder re-chromed can that fill the scratches or is there another process that has to happen to fill them before chroming? I'm assuming repair is my only real option since I doubt whether a decent condition SP81 cylinder can be had for less than a couple hundred bucks? Are there any other cylinders that interchange with a SP81?

This was a real nice looking saw other than the engine damage. Hopefully I can resurrect it without too much expense.

Thanks,
Rob

 

[PogoInTheWoods]

Post pics of the piston and cylinder.

 

[mogulmasher]

Bigblue, damage often occurs on exhaust side first because it's hotter near exhaust port. Those scratches aren't damage from a foreign object physically, it's from lack of lubrication/heat and piston tearing at the bore.

From what I've seen it's usually cheaper to find a replacement cylinder than replating. Typically replating a cylinder cost at least a couple hundred bucks.

 

[BigBlue]

Pictures of the SP81 cylinder/piston damage:

The 'dip' in the edge of the piston is my fault and happened during disassembly... I needed to stop the piston/crankshaft from moving to remove the flywheel nut so I put the plasti-coated handle of a pliers in the exhaust port to prevent movement and apparently the nut was pretty tight...