bogging down under acceleration

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Sep 15, 2003 | 07:46 AM

rusty78

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bogging down under acceleration

I bought my truck back in February and hadn't had a problem with anything until recently. The intake manifold gasket blew out at the rear, causing the truck to backfire through the carburetor. I replaced the intake gasket and had the carb rebuilt. Now, I can get the truck to start and idle fine but it wants to bog down when you press the accelerator. It stumbles whether it's in park, neutral or under load. I've checked the timing and made sure there are no vaccum leaks (it's running at a steady 20 inches of vaccum) and also adjusted the carb until I'm blue in the face. The truck ran fine before the gasket went out so I'm at a loss as to what the deal is. Anybody have any ideas? Thanks in advance.

Sep 15, 2003 | 08:02 AM

rusty78

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bogging down under acceleration

p.s. I forgot to metion that this is a '78 F-250 with a 351m and an automatic. sorry

Sep 15, 2003 | 08:55 AM

ranger429

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bogging down under acceleration

what kind of carb? motorcraft? could be the accelerator pump gone bad

Sep 15, 2003 | 08:57 AM

beartracks

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bogging down under acceleration

You might need to adjust the accelerator pump.

Sep 15, 2003 | 10:33 AM

rusty78

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bogging down under acceleration

It is a Motorcraft 2 barrel. I just had it rebuilt so i figured it should be ok, how do you adjust the accelerator pump? thanks for the advice

Sep 15, 2003 | 12:13 PM

beartracks

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From: Albuquerque

bogging down under acceleration

I think that has the same pump set up as a Holley. With the engine off look down the through the carb and give it a little gas. Choke should be all the way off. You should see an immediate squirt of gas out of the nozzles in the top part of the carb. If not there is a screw and spring assembly that pushes on the diapram lever. That's the adjustment.