Joined: Nov 14, 2008 Posts: 91 Location: Minnesota
Posted: Sat May 22, 2010 6:39 am Post subject: em-bear-assing
My 52 M38, all orginal, starts hard when hot,
1. cold engine--starts first crank
2. when hot, sets about 20 minutes, cranks for 10-15 seconds-sputters, gas smoke until cleared out--!
I hear this is normal due to the carb setting on top of the exchaust manifold, it gets heat soaked , boils the gas out of the carb into the intake manifold causing a rich start when hot.
All ideas appreciated
Do you have the correct insulating gasket between the carb and the manifold?
The unit is upside down in this photo. That V sahped item helps atomize the fuel when it is very cold. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Nov 14, 2008 Posts: 91 Location: Minnesota
Posted: Sat May 22, 2010 9:16 am Post subject:
I have the thick gasket without the metal diverter installed.
My 46 cj2a started with the hand crank when hot, this one never would--is it the difference between carbs, a WO and YS ?
Yes it can be. Proper starting technique is usually the culprit. The lack of a regular accelerator pump is a problem. The starter must be in good shape and spin the engine fast enough to create enough vacuum for the system to work. Full choke and no throttle is the normal way to get her to fire early on.
Most hot starts done shortly after shut down can be made tougher if you haven't addressed the heat buildup and resulting vapor lock issues with the original routing of the line from the fuel pump to the carb. The Army issued a service bulletin moving that tube away from the exhaust manifold.
It is not uncommon for hard starting to act like a fuel issue when hot when in reality a slow turning starter or excessive advance of the ignition timing are the real cause. For the starter check grounds closely and look for corrosion buildup in connections and in the start switch.
The correct timing is 5 degrees advance and a 6 or 7 degree advance is ok for modern fuels.
The starter should be spinning the engine at least 300 to 400 RPM. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
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