m37 carb adjustment...???

Chunk · Post by **Chunk** » Thu Jun 25, 2009 6:26 pm

What is the best procedure for adjusting the carb on an M37? Lets say that the point gap and timing has been set,and valves properly adjusted too. Now... whats the proper procedure?

Joe

Chunk · Post by **Chunk** » Sat Jun 27, 2009 5:04 pm

Charles?

Lifer · Post by **Lifer** » Sat Jun 27, 2009 7:43 pm

You didn't specify exactly what you mean by "adjusting" the carb. If you've had it apart, you will first have to make sure the float is set correctly (the first adjustment). If not, you will need to adjust the idle screw (sometimes called the air adjustment). If the engine will start with it set in its current position, turn the screw in until the engine begins to run rough. Then turn it back out until the engine begins to run rough again. "Happy medium" will be somewhere in between those two points, but a vacuum guage will help you immensely in finding the "sweet spot" for your particular engine. Once you get that dialed in, you can play with the high-speed adjustment so that it idles as slowly as possible without faltering and with no choke applied. If you have the manual, by all means use it! What I have described is pure "shade tree" technique!

MSeriesRebuild · Post by **MSeriesRebuild** » Tue Jun 30, 2009 3:22 pm

Lifer wrote:You didn't specify exactly what you mean by "adjusting" the carb. If you've had it apart, you will first have to make sure the float is set correctly (the first adjustment). If not, you will need to adjust the idle screw (sometimes called the air adjustment). If the engine will start with it set in its current position, turn the screw in until the engine begins to run rough. Then turn it back out until the engine begins to run rough again. "Happy medium" will be somewhere in between those two points, but a vacuum guage will help you immensely in finding the "sweet spot" for your particular engine. Once you get that dialed in, you can play with the high-speed adjustment so that it idles as slowly as possible without faltering and with no choke applied. If you have the manual, by all means use it! What I have described is pure "shade tree" technique!

Lifer's technique is the way to do it. About all I could add is that the correct idle RPM is 600-650. Getting under that allows oil pressure to get really low, excessive idling at an extremely low RPM can cause the bearings to beat out from a lack of oil volume & pressure. Depending on the condition of your engine's oiling system, you may have to idle a little higher to play it safe.