A/C B power unit over heating

Wheat47

Well-known Member
I've mentioned this problem here before. I will also re-post it in the Tractor Talk Board
I've got a A/C model B power unit that was used to repower an early 1281 NH self-propelled baler.
When it gets above 170 deg. radiator temp, it quits. I started baling this afternoon, and it did its thing again, quit.
Which I expected. I checked for fuel flow. Good. However, I touched the carburetor, and it was extremely hot.
I almost blistered my fingers. Upon close examination, I believe the intake/exhaust manifold has an internal thermostatic
device to provide warm air until it warms, then is supposed to allow normal air. (I think.)
I'm wondering if the thermostatic thing is stuck in heat all the time position and causing the carb to boil out the gasoline.
There is a plate, about 2 x 4 on the manifold, held on with two screws. They are well rusted as they get all the heat
from the exhaust. I assume the thermostatic thing is in there, also well rusted. But I don't want to take it off, as I'm sure
the screws will twist off, and then what???
Anyone know anything about this set-up?
Anyone have a diagram of how that works?
Or am I looking for a new/different manifold (most likely!!)??
And of course, I have hay down. It is now 6PM here. In an hour or so, I'm go fire it up and bale as
long as I can, even after dark!!
 
Nothing in the parts book shows a thermostatic system of any kind. I'd find a way to gut it to get the hay done now, then buy an aftermarket manifold and eliminate it all together. That plate is just a cover for a passive heat transfer port.
AaronSEIA
 
From other comments, I think I'm gonna remove that plate, clean out that space see what happens.
I've even thought of putting a small heater fan or blower to blow cooler air over the carb.
Thank you for the reply!!
 
the plate should be a DATA plate that gives valve clearance and timing... Does the motor have a magneto ? I would bet the coil or condenser is getting hot and cutting out... Then OK after an hour of setting... check for spark when it quits.
 
Yes, magneto. I switched Mags. No difference.
Could be a data plate, so rusted, you can't tell.
Thanks for the reply.
 

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