MCCULLOCH The official McCulloch thread

[heimannm]

I haven't seen one of Brian's sets in person so I can't comment on what he's doing but the OEM parts are thin spring steel as you have discovered.











Mark

 

[qurotro]

I haven't seen one of Brian's sets in person so I can't comment on what he's doing but the OEM parts are thin spring steel as you have discovered.

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Mark

Thanks for the reply and the pic! I think I’m missing a gasket under the rubber pump piece. I’m not the first one into this thing.

 

[qurotro]

After some observation of the pics, is there anything under the steel shim? All I have is the shim itself and it seem something is stapled with it.

 

[heimannm]

The OEM piece has a thin cork gasket stapled to it.



Mark

 

[cinci5]

The OEM piece has a thin cork gasket stapled to it.

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Mark

Mark how thick is the spring steel part?

 

[hacskaroly]

The OEM piece has a thin cork gasket stapled to it.

I wonder who was the guy was who said..."let's just staple it" and another engineer said "hey that's a good idea".

 

[qurotro]

Mark how thick is the spring steel part?

Very thin. I believe it's sharp enough to cut your finger.

 

[cinci5]

After some observation of the pics, is there anything under the steel shim? All I have is the shim itself and it seem something is stapled with it.View attachment 444471

There shouldn't be a reason to replace the metal valve unless rusted.

 

[cinci5]

I wonder who was the guy was who said..."let's just staple it" and another engineer said "hey that's a good idea".

It was for the women who assembled them I assume.

 

[qurotro]

There shouldn't be a reason to replace the metal valve unless rusted.

I’m not intending to replace mine. But someone had mess with it before hence gasket is missing.

 

[Sloa]

When my saw was acting like that it ended up being an air leak. It wasn't pulling fuel because there was no pulse. The saw would even fire and run on prime.

Hello, may I ask how I would go about pressure testing. Do I seal at manifold in air box and exhaust. If this holds then check off and if not do I remove tank and repeat with bare intake . Next if fails I remove clutch and flywheel ( soap and water).
I will also get a supply of seats as Mark stated the swelling makes the Flat back unpredictable from day to day.
I do want to run with the flat back but am hedging my options, picked up two tillotson’s. The 63F is in great shape and the 87DT is rough but will get cleaned up. Also aware that a 090 carb can be used as well.
The sdc seems to be a little out of reach.

 

[heimannm]

0.003" thickness for the spring steel valves.

Sloa - remove the carburetor and muffler and make some thick rubber "gaskets" to cover the openings and use the carburetor and muffler to seal the intake and exhaust. An old inner tube works well. You will need to make an adapter to install in place of the spark plug in order to apply pressure and vacuum to test the crankcase.

PTO and flywheel side seals are the most likely source of air leaks so go ahead and remove the clutch and flywheel/points cover and points. It is possible for the gaskets in the intake tract to leak if the screws loosen up. To correct them will require disassembly of the fuel tank since two of the screws that hold the intake down are in the fuel tank. It is also possible for the crankcase cover to crankcase joint to leak; there is an o-ring between the cover and the crankcase itself.

The larger SDC carburetors (SDC18 and higher) have the same venturi and throttle bore size as the MAC and Tillotson HL carburetors used on the saws. There were adapters to allow the use of the SDC on 795L and Super 797 model saws. I am supposed to have some in my inventory but they have disappeared somehow.

Mark

 

[Sloa]

0.003" thickness for the spring steel valves.

Sloa - remove the carburetor and muffler and make some thick rubber "gaskets" to cover the openings and use the carburetor and muffler to seal the intake and exhaust. An old inner tube works well. You will need to make an adapter to install in place of the spark plug in order to apply pressure and vacuum to test the crankcase.

PTO and flywheel side seals are the most likely source of air leaks so go ahead and remove the clutch and flywheel/points cover and points. It is possible for the gaskets in the intake tract to leak if the screws loosen up. To correct them will require disassembly of the fuel tank since two of the screws that hold the intake down are in the fuel tank. It is also possible for the crankcase cover to crankcase joint to leak; there is an o-ring between the cover and the crankcase itself.

The larger SDC carburetors (SDC18 and higher) have the same venturi and throttle bore size as the MAC and Tillotson HL carburetors used on the saws. There were adapters to allow the use of the SDC on 795L and Super 797 model saws. I am supposed to have some in my inventory but they have disappeared somehow.

Mark

 

[Sloa]

Thanks Mark for the instructions on procedure. The super IPL does not show a o-ring at the connection. Read in previous posts 797 called for the o-ring but was dropped in the super and moto seal was used at that point. When I ran it before snow arrived with out the the tank all buttoned up Was able to run about two tanks of gas threw an auxiliary set up and sat rings . Felt confident seals held. After completely together can’t seem to pull gas .

 

[heimannm]

If the only issue is that it won't pull fuel I would concentrate on the carburetor, fuel line & pick up, and the gasket/flange where the carburetor mounts. If the crankcase is leaking so bad that it won't create the pulse needed for the carburetor, the saw could not run at all.

Mark