Backfiring through carb when accelerating hard
Thread Starter
|
New User
Joined: May 2011
Posts: 2
Likes: 0
Backfiring through carb when accelerating hard
I have a 77F250 4WD with a 400. I drove from Wisconsin to San Diego a few months ago and had no issues with the engine. Recently, it started to backfire through the carb when accelerating. I checked the timing and it was was running at 2 BTDC. I adjusted it up to 10 BTDC at idle. This helped. Instead of backfiring all the time when accelerating, it is only doing it when I accelerate hard. I checked the vacuum advance next and the diaphragm was shot, so I replaced the vacuum advance. This seemed to help out some, but it still backfires periodically on hard acceleration. It also seems to be worse after the engine warms up. When it is warming up, I can accelerate any way I want with no backfire. Has anyone else had similar problems?
Cargo Master
Joined: Jul 2010
Posts: 2,099
Likes: 8
From: York, Pa
I would try changing the acc pump diaphragm and double check the stroke like fmc400 said. If that doesn't help I would check the color of your plugs. If your on the lean side they will backfire through the carb more. I had that problem before.
Fleet Mechanic
Joined: Jun 2011
Posts: 1,804
Likes: 5
From: Southern California
Just fixed that same prob with mine. Replace spark plug wires and make sure the firing order is correct. Someone had my spark plug pluged in in the wrong order. IDK how it started and ran. If u need the correct order, let me know.
Mine rund really well now
Mine rund really well now
Thread
Thread Starter
Forum
Replies
Last Post
JeepScrambler
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
3
Oct 24, 2014 10:18 AM
areoseek
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
26
Sep 25, 2013 05:30 PM
evam350
Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460)
12
May 26, 2012 04:52 AM
