Hi,
Just wondering if any of you use an idle stop solenoid to help with engine run-on (aka dieseling) when you turn off your engine?

Occasionally, I have engine run-on when I turn off the key in Park. I've already lowered the idle speed as low as possible, so don't think there's any more I can do there. I know that I can turn off the engine in gear, but would like to be able to turn off the engine in Park.

Attached is a pic of one option: the Holley idle stop solenoid (P/N 46-74) and the bracket (P/N 20-9). According to Holley, this bracket is designed for 4150/4160 baseplates.

Any comments or suggestions are welcome.

Thanks

if it will adjust up enough, and doesn't interfere with any linkage, i would use that.
however, make sure the transfer slot is not exposed. if it is, you will have to make mods to the internals so the transfer slot is not exposed, and the carb will still idle.
the only other option may be to drill a small hole in the primary butterfly's, but that would be a last resort.
i can't say what mods will be needed, as i know virtually nothing about holley carbs, just carterbrock types.
others with much greater knowledge about holley carbs will certainly tell you what to do to solve your problem.

Always used one on a 340-TQ setup.
With idles up around 900-1000rpm, definitely helps.
Get a good solenoid if possible.
When they fail, it's a nuisance, but you just crank up the normal idle screw to get you going again.

If you shut the engine off in gear it will not diesel or run on as long as the idle speed is below 100 RPM or so

I'd like to know if that solenoid has the power to push the throttle open. I would like to find one that would work for bumping the idle up when the a/c compressor kicks on.

I use the idle stops on all my six packs that I restore or tune. I set my transfer slot at .040 with the idle set screws and see if I can tune it to idle correctly at that. IfI can get that setting to work, I set the idle stop solenoid at that point. Then you can back off the carb idle screw enough that it can close off the butterflies and then it should stop the after run condition. I don’t know of a solenoid that can overpower the carb and kick it up. The factory ones that I restore can only hold the tension if you crack the throttle. The repops can’t even do that.

I use the Holley one on my 340. It does not have the power to open the linkage, but it does hold the linkage open once it is extended.

I set mine up for around 850-900rpms in N or P for easy shut down with no dieseling. Then in the drive gears, it idles about 950-1000rpms with the foot on the brake.

YO7_A66:

Does the Holley bracket (P/N 20-9) work with your Holley carb? Or did you need to fabricate your own bracket?

I have a 750 cfm Brawler carb (P/N 67200). It has 2 screw holes near the primary throttle shaft that the bracket attaches to. Attached is a better pic of the bracket and where it attaches on the throttle base plate.

I am using the Holley 20-9 bracket on a QF carb. Since they are both similar, the bracket should mount the same.

When the solenoid/stop is extended, the hex head just needs to hit somewhere solid on your linkage so that it is repeatable.

Typically you have to give a little pedal-push while key is ON (power to Sol.) to extend the plunger before cranking.
None are meant to Push the carb linkage, only to Hold it.

YO7_A66:

Thanks for the pics! Looks like everything bolts up ok.

One last question: does the idle stop solenoid interfere with your air cleaner base? I have a 14 inch open element with a 1 1/4 inch drop base. Is your setup similar?

Good, and the solenoid does not interfere with my 14" drop base air cleaner.