The Stovebolt Site Forums The Shop Area Engine Shop Starting

The 283 in my 49 Suburban doesn't want to start easily after sitting for a couple of days. In order to get it to go I have to pump it fast quite a few times. Once I have it running and shut it off the rest of the day it fires right off on the first rev. Can the Carb be leaking down? I can't smell any gas. The Carb is a 500CFM AFB. I bought it used from a fellow Stovebolter. The only thing I did to it was to oil the accelerator pump leather and convert it to manual choke. The choke seems to have no effect on the running of the engine. Also it uses a LOT of gas. Mileage is about 9/ 10 MPG. Would the fuel pump be the culprit? Anticipating the coming Winter here in Wisconsin I have the truck put up for the season. I have 9 a item list to accomplish before Spring including this starting problem. Maybe I should have left the electric choke on it. All advice appreciated.


Weeds

the mileage may be partly the carb [and choke], but the slow cold start is pretty common, have to pump a few shots in to start a small block that's been sitting for a while - with a manual choke, pulling it half out until it fires should help - do the pumping and choke just an instant before you turn the key - if the choke can be on without affecting a warm engine you have something wrong there, have you looked at the action of the butterfly when you activate the cable?

Bill

Hy Weeds, it sounds like the carb is either leaking, or evaporating the fuel out of it when it has been sitting a while. I know the "Q jets" have a problem with their core plugs (on the bottom of the main body) leaking, most high perf carb rebuilders seal them with epoxy. Maybe someone with experience with AFBs will chime in.

The carb could be leaking. LOT of gas / 9/10 mpg maybe your problem. Float level could be off. While the engine is running at idle, look into the air horn of the carb and see if any fuel is bleeding from main discharge. This check indicates high float level. Check the choke is it open.

Converting to a manual choke is at least part of the problem. If the auto choke is adjusted properly, it's pretty much foolproof- - - -just tap the gas pedal once to let the choke index itself and crank until the engine starts. The electric connection is involved in releasing the choke, not applying it. It should be fully open in 3 minutes if the outside temperature is below 70 degrees, and one minute above 70. Connect the choke heater wire to a switched ignition voltage source, or an oil pressure sensing switch. I prefer the oil pressure method, as the choke doesn't continue to heat itself if the engine stalls.

You might have to tinker with the float level, jets, and/or metering rods to help the gas mileage problem.
Jerry