Carb Question

[dwhite]

I have a Chrysler 251 in my M37 along with the original ETW1 carburetor. There seems to be a flat spot when the accelerator is depressed too quickly. I'm trying to figure out if the vacuum power jet is clogged, or if the carb is just too small for the engine. Ideas? Thanks, Dale

 

[Storm 51]

Try contacting RMS on the G741 website. He is the guru of all things Canadian 251 / M37.

Good Luck with your project!

 

[M543A2]

There is a brass piston in a barrel you can see externally in the top cover of the carb that is held up by engine vacuum against a spring, then drops down from the spring pressure when engine vacuum drops under acceleration to shoot an enrichment jet of fuel into the carb throat by means of a pump in the carburetor bottom it is connected to similar to what is in Carter 4 barrel carburetors. You need to remove the top of the carburetor and check to see that the brass piston moves freely in the top cover and that the pump cup on the bottom of its rod is in good condition. This vacuum operated accelerator pump is why it does absolutely no good to do the old practice of pumping the accelerator on these trucks to enrich for starting. Without vacuum from the motor running, since there is no mechanical linkage from the throttle to this pump, you have no accelerator pump.

 

[dwhite]

Thanks for the help. I'll see if I can find RMS. I'll also take a look at the carb and see if it's operating correctly.

 

[GUNNY 155]

Accelerator pump problem is the likely problem but also check the timing with a timing light. Late timing can also be an issue.

 

[dwhite]

Thanks for your suggestions! I've gotten a couple of replies to check the timing first. Apparently these engines are very sensitive to timing. I'll also check the accelerator pump. Unfortunately I'll need to wait a little for the weather to warm up. Right now is -5F!!