B with Exhaust lift

[DoubleJFarmsWA]

So, I have a B that has the exhaust lift on it (and 2 one way plows). We rebuilt the cylinder leather cup seal, and reassembled. I read on here that we should add a little oil daily to the cylinder. I am currently rebuilding the carb, as it was not working good, and am thinking that may be one reason the lift is not lifting the plow. Attached is a picture, of part of the exhaust lift, what is it?

[Jim Becker]

That is the control valve. In simple terms, it is a check valve. The system has 3 main components: pressure valve, control valve, and cylinder.

The pressure valve is located on top of the exhaust manifold. When closed, it forces exhaust to pass through the control valve to the cylinder. Failure of this valve to close tightly is a main cause of failure to lift. Rust is the main problem. It needs regular maintenance.

The control valve has a check valve with a neoprene washer as the valve seat. When operated to lower the lift, a disk is pushed off the seat. Deterioration of the washer can keep the lift from staying up. Swelling of the washer can sometimes prevent the lift from lowering. Running the engine with the hose that connects to the cylinder open tends to overheat this valve and contribute to deterioration of the washer.

The cylinder is fairly self-explanatory. It needs a regular dose of oil to keep the leather seal in condition.

[DoubleJFarmsWA]

so, I rebuilt the carburetor, and put some oil in the exhaust lift cylinder. The B will lift the plow to latch, if someone gooses the throttle linkage above what the governor is having it run at. I tried adjusting, and have the low idle at 560, but with full throttle it only goes up to 1260, and I believe it should be up to 1400ish. I tired lengthening the rob from the governor linkage to the carb (2 turns), to push the throttle more open. It did not appear to help.

[Jim Becker]

. . . I tired lengthening the rob from the governor linkage to the carb (2 turns), to push the throttle more open. . . .

Yeah, that won't help. That link is adjusted with the engine off. Remove the pin, push the throttle control fully forward and pull the disconnected linkage fully back. This sets both at wide open. Adjust the length of the link so the pin will just slide in without moving the other parts.

You should easily get high speed idle up to 1,540. (1,400 is rated speed at full load.) You adjust fast idle speed with the high speed adjusting screw, a cap screw on top of the governor housing. It will be screwed in part way with a lock nut holding it in place. Loosen the lock nut then back the screw out a little at a time until you get the right speed. Then lock it in place with the lock nut.

My experience is that you need the engine pretty well rev'ed up for the lift to work. If it doesn't after you tweak the engine speed, you may need to clean up the pressure valve. Rust causes problems with them.