Hard Starting Hot

[Rich72C10]

I got the returned carburetor installed this morning. I have to say, it's much easier to get her to run down the road without her falling flat on her face. I think I got her dial in okay, though on Tuesday I'll have my shop take a look (she is going in to relook at my rear end leak). The difference is night and day but it is apparent I am no carburetor tuner. This is even with my fancy timing light (to watch for max idle) and vacuum gauge (to watch for max vacuum)!

With that said, I still have these problems:

1. Can't get the anti dieseling solenoid to do its job, still idles ~500 RPMs when solenoid is disengaged.
2. The above is with the throttle closed, of course, and the high pitched whistling is still there. The whistling goes away once I adjust above 600~650 RPMs.
3. The left (passenger) adjustment screw is still really loose, lots of wiggling. The right (driver) seems okay, especially compared to the left. I haven't any idea what issue this could cause, if anything - other than perhaps being able to fine turn the mixture on that side of the carburetor.

Seems the "whistling" would be a air leak, which in turn allows the engine to still idle, even though the throttle is fully closed.

Edit:

From Mark @QuadraJet Power

It is idling at 500 now? That is so low that the anti dieseling solenoid would not be effective. I thought that solenoid was primarily utilized to kick up the idle speed when the ac was turned on.

With throttle blades closed and low idle speed, the carb is pulling air through every possible point. Throttle blades are typically open slightly to get proper idle speed and allow the flow through the primary blades. Your carb, as with most, has a bypass air system to allow some air with throttle blades mostly closed. Might have a sound if you try to force all the air through the bypass.

Idle adjustment screws often wiggle. No problem.

I am a bit disappointed that it seems they haven't any clue as to the operation of the GM Stop Solenoid / Anti-Dieseling Solenoid.

[Carl Spangler]

Originally Posted by Rich72C10

I got the returned carburetor installed this morning. I have to say, it's much easier to get her to run down the road without her falling flat on her face. I think I got her dial in okay, though on Tuesday I'll have my shop take a look (she is going in to relook at my rear end leak). The difference is night and day but it is apparent I am no carburetor tuner. This is even with my fancy timing light (to watch for max idle) and vacuum gauge (to watch for max vacuum)!

With that said, I still have these problems:

1. Can't get the anti dieseling solenoid to do its job, still idles ~500 RPMs when solenoid is disengaged.
2. The above is with the throttle closed, of course, and the high pitched whistling is still there. The whistling goes away once I adjust above 600~650 RPMs.
3. The left (passenger) adjustment screw is still really loose, lots of wiggling. The right (driver) seems okay, especially compared to the left. I haven't any idea what issue this could cause, if anything - other than perhaps being able to fine turn the mixture on that side of the carburetor.

Seems the "whistling" would be a air leak, which in turn allows the engine to still idle, even though the throttle is fully closed.

Edit:

From Mark @QuadraJet Power


I am a bit disappointed that it seems they haven't any clue as to the operation of the GM Stop Solenoid / Anti-Dieseling Solenoid.

FWIW, I always assumed the anti-dieseling solenoid was ONLY intended to stop dieseling when the ignition is off. The solenoid wasn't intended (when off) to kill the engine when the ignition is ON.

That said, I feel your carb pain! If it makes you feel any better, I think I've had my 1 barrel Rochester apart at least 20 times in my quest (finally achieved) to get my truck to run sweet.

[Rich72C10]

Originally Posted by Carl Spangler

FWIW, I always assumed the anti-dieseling solenoid was ONLY intended to stop dieseling when the ignition is off. The solenoid wasn't intended (when off) to kill the engine when the ignition is ON.

That said, I feel your carb pain! If it makes you feel any better, I think I've had my 1 barrel Rochester apart at least 20 times in my quest (finally achieved) to get my truck to run sweet.

That is correct on the Stop Solenoid. But I can remove the idle screw and turn back the Solenoid screw all the way back and it idles 500 rpms. On my old Carb she plan dies. My assumption, which could be wrong, if the carb doesn't die (staved of air/fuel?) - it can still diesel. On the visor instructions, it stays to hold the gas pedal a bit when warm to get it started - which makes sense as the solenoid isn't strong enough to push up the throttle.

I think @Steeveedee was correct. I just used a good bit of "Can of Air" on the choke coil to freeze it (can upside down while spraying the coil). It looks like I was letting the choke plate close way to much, which points to me being sloppy on the adjustment yesterday. As for the vacuum thingy, it's working like a charm.