Hi all, I am new to this forum and am having problems with my 65 mustang. It has a 289 that I built 10k miles ago, it's relatively stock, bored .20 over with a edlebrock 1406 carb and a HEI distributor. Well it ran damn near perfect until a couple weeks ago when I tried to drive it. It would drive fine up to about 65-70 mph, and then it would start to stutter. Well it has gotten a lot worse since then. So I tried a few thing to fix it. I replace fuel filter and pump, pickup coil and modulator, and cap on distributor, new spark plugs.... No luck, so I pulled the carb off to check the float levels and clean the screens in the carb. The float levels were off and the screens were pretty dirty so I though this would be the problem for sure, I put the carb back on an still no luck. So I pulled the heads to check for any burnt valves or any other problems, my exhaust valves were pretty nasty and needed to be reseated, so I got new valves, got them back from the machine shop, torqued everything down, adjusted valves. When I started it up everything seemed fine, it would rev up like nothing was every wrong, then the next time I started it.... It was back. So I am asking for y'all's advice and wisdom, I don't know what else it could be, I uploaded a YouTube video so you could see what I am talking about. Thanks a lot!

http://youtu.be/YifPx7pPR3E

 

Trash the carb, wrong tuning and it's getting pissy as weather changes, possible culprits.

The only things that really change over time like that (usually) are fuel, trash in the fuel building up, and wear with ignition components.

What cam did you use and did you break it in properly? What oil did/are you using?

 

It doesnt have the manual choke does it? Manual choke is the best thing ever if you are lucky enough to have one simply drive to the speed at which is begins to stumble then slowly add choke until the problem goes away or gets worse.

If adding choke clears up the problem you almost 100% have carb issue probably plugged up high speed circuit if it gets worse when adding choke it could be ignition or some other issue.

-Gun

 

hello;

first, if you have distributor vacuum advance disconnect and plug it.

set your initial timing between 12 and 14 for now.

if its still bad leave the hose disconnected.

why were your ex valves bad after 10k miles? whoever built that engine should be fired.

what exactly was wrong with them?

your idle circuit "sounds" ok.

the prob is either your carb or your ignition. it sounds electrical to me.

what carb is it?

if its a holley the gas level should ve just below the inspection window. if gas pours out when you remove the screws then the level is too high.

if the carb is an edelbrock, take it off and give it to someone you hate really bad.

if you have an msd bypass it.

if you have pertronix, put the points back in it

try a different set of plug wires even if yours are new

try a different coil

is your original pink ignotion wire still used or was it bypassed for some fancy crap ignition stuff?

 

Did it sit for a while? I'd siphon out the gas, and add all new fresh. The fuel today goes bad pretty quick. If you parked it for the winter, I'd change the gas out.

 

Okay, so new carb (Holley 670) new plug wires and new ignition coil..... No luck! And it didn't sit for a while, it was my daily until it started acting up. I've never been so stumped

 

did it have this prob before you installed the new wires and coil.

if not then try everything in post 4 then get back to us.

 

It's acting exactly the same as earlier, even with then new carb, coil and wires. How do you bypass a MSD? The distributor is a GM style HEI from summit racing

 

so the answer to this is yes?

do you have an msd?

does it have points?

 

Yes it did have the problem
And this is the distributor I have http://www.summitracing.com/parts/sum-850022/overview/make/ford