Model M crawler engine

VCguy

Member
A friend of mine just bought a 1936 model M crawler that wasn"t running. He replaced plugs, points and condensor, rebuilt the carburater, replaced radiator core, adjusted valves, rebuilt water pump, cleaned out fuel tank and istalled new sediment bowl and filter. The engine starts and runs on all 4 cyliners but will only idle. The throttle shaft on the carb turns when hand lever is moved but rpms don"t change. Also water in radiator boiling after running about 5 minutes but temp gauge only shows 180 degrees. (new gauge) Any ideas on the throttle and cooling system problems. Thank you for your help.
 
First off i would say radiator is blocked and or water pump not working.2nd the govener rod is stuck is the slide and will not move you have to free it the try again,Also if you have had the carb off make sure the little tab is located in the correct place on the cross shaft,or 1 last thing the linkage is binding.
 
hi
the lack of throttle control is probably the sleeve around govenor spring stuck in its bore, remove the side plate behind mag and you will see the throttle shaft with spring on right hand side. you may be able to free the sleeve from here but will probably have to remove the radiator and gov cover to tap it in and out.
overheating open rad cap with engine running and check for cirulation you should see water flowing from top hose and down into core, is no or low flow remove top tank from rad. i know core is new but when engine is started rust flakes are pumped out of block and block top of core. if this is clear and it has not had a later thermosat added the problem may be the water space in the block fill of rust the only real why to clean out fully is to pull the liners, i Know people who have had success with a lye solution the process is fill rad with solution run till boiling drain and flush repeat as neccessary at your own risc...
 
When throttle lever is moved the governor linkage moves and the throttle shaft in the carb turns (took the triangular cover off end of throttle shaftand it moves) which indicates to me that there still might be a problem in the carb. Just had carb rebuilt but I guess there still could be a problem in it. It was doing the same thing before carb was rebuilt. As far as the overheating problem, even though radiator has a new core, there could have been junk in the block and head which have now blocked tubes in radiator. May end up taking top tank off radiator and checking for blockage. Thank you for the suggestions. Any other thoughts on the throttle issue?
 
(quoted from post at 08:20:36 04/26/13) Yes, it has a water pump. Been rebuilt.

Does it have a thermostat? You don't mention that, so I thought I would ask. It could be sticking.
 
Hi
I still think the throttle problem is the gov sleeve. I bet you only see the throttle shaft at the carb move with the engine stopped you could try to prove this by turning the shaft by hand from behind if the spring loaded cover is missing or with a pair of grips on the outer end of shaft. Note if you run engine with economise cover removed (cover with 3 screws) i think the engine is likly to run rich at idle.
 

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