What else could it be?
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New User
Joined: Jan 2005
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From: South-Eastern PA
What else could it be?
Hey guys. My 78 f150 w/351M and holley 4bbl has a rough spot when I'm on the gas after the engine is warmed up. In the past 2,500 miles I've done carb rebuild, new plugs, wires, cap, rotor, fuel filter and set the timing, fuel mix and float level.
It was running great for a long time (majority of the 2,500 miles) until about two weeks ago. Now it has this rough spot, almost a hesitation/stumble. Doesn't seem as bad when cold or at higher rpms.
Tried my spare ignition module today and rechecked the float level and tried a few different timing settings...now I'm back to 14 degrees btdc. Engine still acts the same.
I've been searching the site for a while now, all the suggestions to cure hesitation seem to be the things I've tried.
I guess power valve is next, unless someone here has another suggestion.
Thanks
It was running great for a long time (majority of the 2,500 miles) until about two weeks ago. Now it has this rough spot, almost a hesitation/stumble. Doesn't seem as bad when cold or at higher rpms.
Tried my spare ignition module today and rechecked the float level and tried a few different timing settings...now I'm back to 14 degrees btdc. Engine still acts the same.
I've been searching the site for a while now, all the suggestions to cure hesitation seem to be the things I've tried.
I guess power valve is next, unless someone here has another suggestion.
Thanks
Thread Starter
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New User
Joined: Jan 2005
Posts: 11
Likes: 0
From: South-Eastern PA
Thanks guys.
Yeah, I'll probably throw in a new power valve tomorrow first thing, eliminate that possibility.
I have checked the carb for obstructions.
The dizzy is definitely tightened down at 14 degrees btdc.
I've always run 93 octane...could it be this higher alcohol content gas?
Should I tune it differently from the stock settings?
Maybe I'll pull the spark plugs again tomorrow too.
Yeah, I'll probably throw in a new power valve tomorrow first thing, eliminate that possibility.
I have checked the carb for obstructions.
The dizzy is definitely tightened down at 14 degrees btdc.
I've always run 93 octane...could it be this higher alcohol content gas?
Should I tune it differently from the stock settings?
Maybe I'll pull the spark plugs again tomorrow too.
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Thread Starter
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New User
Joined: Jan 2005
Posts: 11
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From: South-Eastern PA
Problem solved...dizzy...thanks for the help guys!!!
It was the dizzy. Pulled it and it had a catch while spinning it, I guess the bushing was shot. So, got the new dizzy in today and the truck is running great. Good acceleration bottom to top, nice idle and no hesitation or flat spots. Dad said I even smoked the tires pulling away from the garage on the fist round the block after setting the timing.
Thanks for the help guys.
Thanks for the help guys.