Back fires through carb
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Back fires through carb
i have a 79 f 150 with a just rebuilt 351m stock distributor and a new Holley 4160 carb. my problem is is that when i put it to the floor it backfires through the carb but not once it has some speed going. it also just doesnt feel like it has the power it sould have. i checked the vacume advance and initial timing every thing is fine any suggestions. It also just doesnt have the power it should have.I think it might need richer jets
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Joined: Dec 2001
Posts: 22,436
Likes: 17
From: Louisville,Ky.
Back fires through carb
May need a different squirter in the carb. I believe that most of them come with a #25. I would maybe try a 28. I would also drive it normal for about a week then pull the spark plugs to see how they look, if they are white, it is too lean and needs bigger jets. if they are black then it may need smaller jets. Also, check for vacuum leaks ans make sure that there isn't s screw in the secondary throttle linkage to make it open manually. This will cause a major bog and backfire due to there is no accelerator pump for the rear barrels and they are designed to open slowly.
Jimmy
PS. Is the vacuum advance hooked up on the passenger side port coming out of the metering block just in front of the choke? It should be.
Jimmy
PS. Is the vacuum advance hooked up on the passenger side port coming out of the metering block just in front of the choke? It should be.
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Back fires through carb
Im going to try the different squirter size and maybe a more aggressive accelerator pump cam..How would i go about taking the squirters out and should i change only the primaries or both. As for the timing i have already advanced it more and it didnt get much better just a little.
Moderator
Joined: Dec 2001
Posts: 22,436
Likes: 17
From: Louisville,Ky.
Back fires through carb
It only has one set. It is in the front, and is located in the center of the front barrels closest to the front rim and is held in by a phillips head screw. Just unscrew the screw, you might want to hold the assembly with needle nosed pliers so that you don't drop anything down the carb. Also, there is a gasket under the screw and under the squirter. Make sure that you put new ones on the new squirter.
Jimmy
Jimmy
