McCulloch Chain Saws

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Thanks! I get placing rubber between case and muffler, but how do you hook up the pressure tester to the intake? Some sort of purchased fitting, or is it homemade?

Do the same for the intake except add a nipple for your hose. No machining required. Drill, tap or tight press fit and use sealant.
Ron
 
I have been watching some videos about Bob Walker and building a custom full circle crank shaft for a saw instead of an offset one. Does the Sp81 have a full circle crankshaft counterweight? If it doesn’t would this be possible for a machinist to build? I know a very good machinist. He’s good and would probably grumble about the left hand threads. Would that be possible for an average machinist? He is better than average.
I'm a retread machinist and to answer the question. It is a lot of very close tolerances kind of work. Can be done with some good equipment and lots of time. Probably be high 000.00 or low 0000.00. Myself I'm not sure if the gain is worth the price, maybe for a race saw where the money doesn't matter. Just my. .03 cents
 
Do the same for the intake except add a nipple for your hose. No machining required. Drill, tap or tight press fit and use sealant.
Ron
If one can just bolt a plate over the intake with drilled and taped fittings then problem solved, If it is a saw with a type of pipe or tube as part of the intake is what I was talking about. This is just to make it a bit more clear.
Thanks.
 
I'm a retread machinist and to answer the question. It is a lot of very close tolerances kind of work. Can be done with some good equipment and lots of time. Probably be high 000.00 or low 0000.00. Myself I'm not sure if the gain is worth the price, maybe for a race saw where the money doesn't matter. Just my. .03 cents
Retired? Your better then "retread" Todd.
 
0331201835.jpg
Here is where I'm at so far. Couple questions... The house on the back under the handle has all the screws out but wont come loose. Do I have to take the gas tank off first? Also the flywheel nut is proving difficult. Should I try some penetrating oil? Or just more muscle?
 
So am I better to block carb/case and use the spark plug hole?

You have to block the intake, exhaust and plug. I don’t know if there Is an ideal opening to use for the hose. Some modify a spark plug and others put it in one of the blocks. I believe the MAC factory kits used the intake block - there are folks here that know. There used to be pictures here but I cannot find them.

Ron
 
View attachment 813083
Here is where I'm at so far. Couple questions... The house on the back under the handle has all the screws out but wont come loose. Do I have to take the gas tank off first? Also the flywheel nut is proving difficult. Should I try some penetrating oil? Or just more muscle?
If you don’t have an IPL for your saw, get one. A picture is truly worth a 1000 words.
Ron
 
If you don’t have an IPL for your saw, get one. A picture is truly worth a 1000 words.
Ron
I do have the IPL. I guess I need to read more. I got the service manual from the beg for manuals thread, but I cant print it off until I get to work on Thursday... Stupid Covid 19 :)
 
View attachment 813083
Here is where I'm at so far. Couple questions... The house on the back under the handle has all the screws out but wont come loose. Do I have to take the gas tank off first? Also the flywheel nut is proving difficult. Should I try some penetrating oil? Or just more muscle?
There is a small bolt inside the airbox to the rear where the throttle linkage comes thru. There are 2 small bolts at the carburetor with a keeper for them. And there is a bolt inside the oil tank for the front. Youll also have the oil rod so once the front bolt is out then sorta pull backwards and itll pop off. Also a gasket for the insulator. Sometimes they are sticky.
 
A piece of inner tube on both the exhaust and intake works fine to seal them with block off plates if you're using a spark plug adapter for the injection point. I don't find the application of an actual sealant to be necessary. In the absence of block off plates, just slide pieces of rubber between the muffler/exhaust and the carb/intake as block off adapters and test away.

If using the intake as the injection point, fashion an adapter that will fit across the entire assembly to include both spacers on either side of the tank and ensure the integrity of all the adjoining surfaces and associated gaskets. A piece of aluminum stock with a barbed fitting is easy to make and works great for an intake adapter. A busted off spark plug with some rtv and an old piece of fuel line or barbed fitting works for a spark plug adapter. I use an 'O' ring also instead of relying on the metal washers to seal the plug adapter at the threads.

Always test both pressure and vacuum. A vac leak at a crank seal can often be closed by pressure.
 
I don’t post much like I used but I still keep a watch on you guys to make sure you’re behaving.

Cleared 5 dying trees today that’s been bugging me for a couple years. Got sidetracked and didn’t picture the large one.

d75f9cb88fa924702d0aac93433071ce.jpg


22b22ff7a9fe54665afda910d7973fba.jpg


All the old Macs still kicking butt.
 
A piece of inner tube on both the exhaust and intake works fine to seal them with block off plates if you're using a spark plug adapter for the injection point. I don't find the application of an actual sealant to be necessary. In the absence of block off plates, just slide pieces of rubber between the muffler/exhaust and the carb/intake as block off adapters and test away.

If using the intake as the injection point, fashion an adapter that will fit across the entire assembly to include both spacers on either side of the tank and ensure the integrity of all the adjoining surfaces and associated gaskets. A piece of aluminum stock with a barbed fitting is easy to make and works great for an intake adapter. A busted off spark plug with some rtv and an old piece of fuel line or barbed fitting works for a spark plug adapter. I use an 'O' ring also instead of relying on the metal washers to seal the plug adapter at the threads.

Always test both pressure and vacuum. A vac leak at a crank seal can often be closed by pressure.
I know about the pressure testing did not really think about the vacuum test. Makes sense thank you.
 
I don’t post much like I used but I still keep a watch on you guys to make sure you’re behaving.

Cleared 5 dying trees today that’s been bugging me for a couple years. Got sidetracked and didn’t picture the large one.

d75f9cb88fa924702d0aac93433071ce.jpg


22b22ff7a9fe54665afda910d7973fba.jpg


All the old Macs still kicking butt.

Good to see ya round again. Still have a dozen 82cc's?:)
 

Latest posts

Back
Top