it seems like its a new thing every week. i timed it, it ran good for a week, carb accel pump wasnt working, so i rebuilt the carb. ran good for a couple days, now it seems like the same damn problem, its like a hesitation like when the accelerator pump was bad just not as severe. and its only under load. my accelerator pump is pumping just as it should i dont know what else it is since i just cleaned and rebuilt the carb 2 days ago, unless my fuel filter could be plugged up? what do you suggest? what could be the problem

 

If it has a screw in filter on carb definatly change that. Change any others while you're at it. Check vacuum line to distributor, vacuum leaks, especially since you just had it off. Don't think the filters will your problem though, with it only happening under load.

 

My truck was doing the same thing, seems the spring on the adjust screw was worn and it would wiggle out after a little while, also the bolt for the timing was loose and it would move under acceleration.

 

im not running any vacuum advance because it seems to advance way too much, ive tried with it and without it and i have the same problem, i have no vacuum leaks either ive tested for vacuum with a gauge.

 

im using an old screw on filter as an in line cus its all i had, but i just remembered dont the carb to intake gaskets blow out a lot on the edlebrock performer 400. someone told me there was a spacer for it that prevented it from happening, which i dont have. ill throw it on the vacuum gauge again see what i get maybe just check that gasket

 

All street engines need to run a vacuum advance. What do you mean it "seems to advance too much?" Is the engine pinging at cruise? That's another problem that simply gets revealed by the vacuum advance - the vacuum advance is not the actual problem.

If you did not replace the fuel filter when you rebuilt the carburetor, you must do that.

What did the vacuum gauge say? There are few situations where the engine can have a healthy vacuum reading, but run poorly - unless the issue has zero interaction at idle (which doesn't sound like it's the case if it's off-idle that the issues shows up).

 

what i mean is that its advancing more than 60 degrees under load and it does start pinging under load. and i just set the timing to 10 degrees advanced. I've been told 60 degrees is way too much, and I've been running this truck with no vacuum advance since i got this truck and with ones before it, I've never had a problem until now. i haven't had the time to look at it yet this week, but i will this weekend, i will let you know what vacuum is and if i find a solution, till then any other suggestions are welcome

 

well more than 60 degrees revving the engine up with no load,

 

Time for a new Vac Adv canister. Yours has a failure in the total advance stop mechanism inside.... It is going to a ported connection on the carb though; right?

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one would think that... thats what i thought int the first place so i bought a whole new distributoor because i went through this problem once thinking that before, are tyou certain that that is the only cause for that problem to happen? its 60+ degrees revving the engine up in park

 

what is a normal amout of advance? could i be getting too much vacuum? i have edelbrock performer 400 intake and performer carb

 

and this is a 79 f250 400 btw

 

Here is a link regarding initial timing, curving, vacuum and total advance if you would like to read:
Carbed Ford Message Board :: View topic - The Ultimate Duraspark Ignition Timing Guide

 

Very good info! I never knew that up to 60* might be acceptable....

From the post/article:
Thanks gfw 1985! I always thought the high 40's was max....

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ok, i just read that whole article and it was very helpful, now i have one question, vacuum advance is supposed to use manifold vacuum? i did a lot of asking around and not once did someone say manifold vacuum, i was under the impression vacuum advance was for when you want to accel fast and the centrifical advance wasnt enough. so either was a vacuum advance wasnt my problem because i experience this issue at Close to WOT or WOT, anything below half throttle is fine