My 65 Mustand hesitates at accelateration. It happens bad in first and 2nd gears.. then after it gets going a bit its not as bad.. I had the oil, Tranny and Diff fluids changed this weekend.. and the hesitation got worse and it backfired all the way home.. I rencetly changed the air filter and was told to try the fuel filter.. but then somone just told me that was highly unlikely. after the backfire incident I sprayed carb cleaner on the carb area and the backfiring stopped but it still hesitates.. HELP!

SIDE Note the Carb (single barrel ) was rebuilt about 3 months ago.

 

i assume you have a 6 cylinder. change the fuel filter its cheap. also check your timing

 

mabeye some crud got pushed around the carb, and is blocking some passages. could happen after a rebuild

 

could be a timing issue, or maybe the carb i think. maybe the accelerator pump on the carb is not giving it a full shot. it could possibly even be a short, check for cracked spark plug wires or burned points. good luck!

 

demon is on the most likely problems: timing or accelerator pump. That is, if what you are describing is what we think of as hesitation. A better term might be "stumbling."

If it is running out okay at high speed, the fuel filter is likely not the problem, but as said earlier, it's cheap and easy to replace. It never hurts to have a fresh filter.

SOoo.. Start by taking off the air filter and peering down the throat of the carburetor while giving it a quck shot of the throttle, WITH ENGINE OFF. You should see a small stream of raw gas come out of the accelerator pump nozzle. If not there is your problem. If you do see the gas, then check the timing.

It is likely that one of these areas will be your problem.

 

I have checked the carb and there is gas being released witht he engine off.. I will check the points today.. I am struglgling with getting the hosuing off of the fuel filter! the mechanic that rebuilt the carb told me that he hasnt seen a dirty fuel filter on a 65 in 20 years.. and sad that was prolly not my problem.. but it would be nice to at least eliminate that ! its so strange that it idles so nicely.. but the minute i try to drive its jerky and hesitates.
THanks for your tips!

 

he probably hasnt seen a 65 in 20 years lol, gas tank rust is a problem on these old cars.

 

The timing is checked with a timing light. Most auto mechanics these days haven't
even seen a carborator, let alone a timing light. And it probably wouldn't be worth buying one, you won't use it much.
Get to a shop that specializes in old cars, preferably Mustangs. They could easily fix your problem. Have them put in a Pertronix kit that eliminates the points too, then you'll never have to mess with them again. It's a simple device that hides under the stock distributor cap, but it works quite well.
Are you in the bay area? Mustang Fever is an excellent shop here in south bay near San Jose.

 

I think my exhsuband has a timing light I can borrower maybe he woudl be nice and do it for me.. the mechanic that rebult the carb is a Vintage guy in Novato. I am in the North Bay..I would take it to Novato but really trying to stretch my dollars these days.. thus.. asking the gallery thank you for all the input.. I am thinking Timing, fuel filter/pump are where i am starting!

 

Many mechanics are puzzeled at failed engine parts that only cost $3, like fuel filters, lol. They seem to be experts on jobs that cost at least 3 figures. With the backfiring, it sounds like a timing issue.

If you have $100-$200 (total cost-parts and labor) you can spare, go for a pointless ignition. Your timing will stay steady, and you will never have to change points again. I have a Petronix Pointless system that fits within the existing distributor cap and it works great. Do some digging online. You can even find DIY sites with pics if you want to install yourself, but you'll need a timing light. Good luck.

CP