The Ford Barn

bill h · 07-21-2014, 11:54 AM

1947Ford adjustable mallory electronic ignition and dual strombergs. .I've been having problems with ignition timing which I have now set with a vacuum gauge 19lbs steady at idle. I have not yet made timing marks. Previously it idled at 500 rpm's. The only problem was the idle screws were backed off completely having no contact but drove fine. Since I have advanced the timing naturally the idle has increased and (800) now the problem is to decrease the idle. The car runs great and doesn't appear the ping.i have disconnected the linkage and there is no binds just no way to decrease the idle. The carbs were rebuilt at one point but since I've used them with this set up I could not decrease the idle. Any thoughts. Thanks as always

ford38v8 · 07-21-2014, 12:10 PM

Bill, crank the idle mixture screws all the way closed, then open them both to 3/4 turn open. Start and warm up the engine, then find the sweet spot with each idle screw. This will also mean adjusting the idle speed on the throttle, as right now your idle speed is controlled by the volume of gas entering rather than the volume of air.

supereal · 07-21-2014, 12:31 PM

I'd suspect one or the other of the Stromberg carbs is leaking gas internally. It is also possible that you have a vacuum leak, such as a cracked or loose wiper hose. My experience with Mallory ignition is that they are very tricky to set correctly, particularly with dual carbs.

bill h · 07-21-2014, 12:43 PM

The problem is with the throttle screws. I can take them off and take off the linkage and through them away and I still idle at 800 rpm. I don't think I have a vacuum leak. I've checked and a vacuum is a a very steady 19lbs. Thank Bill

51 MERC-CT · 07-21-2014, 01:04 PM

Quote:

Originally Posted by bill h

The problem is with the throttle screws. I can take them off and take off the linkage and through them away and I still idle at 800 rpm. I don't think I have a vacuum leak. I've checked and a vacuum is a a very steady 19lbs. Thank Bill

Do as 38v8 says, adjust idle mixture screws first then play with curb idle.

OLD...BILL · 07-21-2014, 02:32 PM

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Hey Bill: The throttle plates are not closed...find the one screw on the right side in the linkage, IS this the idle screw your talking about ?? push the linkage back to close the throttle plates, you may have a bent shaft, or the plates are worn or bent, and leaking ... disconnect the accelerator pump rod, it may be holding you open ?? or on the wrong post.??.... ALL the " air / fuel Mixing " screws are out 1-1/2 turns out, on both carbs. ??
So whats next ? a leak in the system, intake to block, carb base to intake. but...but I never took it apart... one good calf back or back-fire, can displace a small, maybe lose gasket and start to leak, I use a big no,,no..no .. big boom ,, fire,,no..no can't use that SSOOOO WD-40 is the least boom / boom,... Maybe some light weight oil, around the carb, base or the intake, and watch it disappear, and the engine RPMs change up or down ?? OR.. put the original distributor back in service...for a test ?? ( one of the best there is ) the old crab is hard to beat...... OLD.....BILL

07-21-2014, 11:54 AM	#1
bill h Senior Member Join Date: May 2010 Location: Toronto Ontaro Posts: 129	Engine idle 1947Ford adjustable mallory electronic ignition and dual strombergs. .I've been having problems with ignition timing which I have now set with a vacuum gauge 19lbs steady at idle. I have not yet made timing marks. Previously it idled at 500 rpm's. The only problem was the idle screws were backed off completely having no contact but drove fine. Since I have advanced the timing naturally the idle has increased and (800) now the problem is to decrease the idle. The car runs great and doesn't appear the ping.i have disconnected the linkage and there is no binds just no way to decrease the idle. The carbs were rebuilt at one point but since I've used them with this set up I could not decrease the idle. Any thoughts. Thanks as always

07-21-2014, 12:10 PM	#2
ford38v8 Senior Member Join Date: Jul 2011 Location: SF Bay Area Posts: 6,634	Re: Engine idle Bill, crank the idle mixture screws all the way closed, then open them both to 3/4 turn open. Start and warm up the engine, then find the sweet spot with each idle screw. This will also mean adjusting the idle speed on the throttle, as right now your idle speed is controlled by the volume of gas entering rather than the volume of air. __________________ Alan

07-21-2014, 12:31 PM	#3
supereal Senior Member Join Date: Jul 2014 Location: Iowa Posts: 1,634	Re: Engine idle I'd suspect one or the other of the Stromberg carbs is leaking gas internally. It is also possible that you have a vacuum leak, such as a cracked or loose wiper hose. My experience with Mallory ignition is that they are very tricky to set correctly, particularly with dual carbs.

07-21-2014, 12:43 PM	#4
bill h Senior Member Join Date: May 2010 Location: Toronto Ontaro Posts: 129	Re: Engine idle The problem is with the throttle screws. I can take them off and take off the linkage and through them away and I still idle at 800 rpm. I don't think I have a vacuum leak. I've checked and a vacuum is a a very steady 19lbs. Thank Bill

07-21-2014, 02:32 PM	#6
OLD...BILL Senior Member Join Date: May 2010 Location: Northern California,coast Posts: 552	Re: Engine idle Sponsored Links (Register now to hide all advertisements) Hey Bill: The throttle plates are not closed...find the one screw on the right side in the linkage, IS this the idle screw your talking about ?? push the linkage back to close the throttle plates, you may have a bent shaft, or the plates are worn or bent, and leaking ... disconnect the accelerator pump rod, it may be holding you open ?? or on the wrong post.??.... ALL the " air / fuel Mixing " screws are out 1-1/2 turns out, on both carbs. ?? So whats next ? a leak in the system, intake to block, carb base to intake. but...but I never took it apart... one good calf back or back-fire, can displace a small, maybe lose gasket and start to leak, I use a big no,,no..no .. big boom ,, fire,,no..no can't use that SSOOOO WD-40 is the least boom / boom,... Maybe some light weight oil, around the carb, base or the intake, and watch it disappear, and the engine RPMs change up or down ?? OR.. put the original distributor back in service...for a test ?? ( one of the best there is ) the old crab is hard to beat...... OLD.....BILL