Stumped! Possibily solved!

[woodbutcher]

Have you considered that the carb OR the adapter might be afflicted with a POROUS casting that won`t show up as a vacuum leak until the engine warms up.
Have you checked the adapter carefully for any hairline cracks that would permit a vacuum leak as the engine warms up?
Good luck.Have fun.Be safe.
Leo

 

[Frankenstang]

Got up this morning and swapped in a spare set of points I had and it fired right up, all cylinders firing, idling smooth. Slowly started missing within a minute till back where I started.

:idea: Did you change the condensor along with the points? Just spit ballin here...Also you mentioned 'known' good coil, but have you tried a new one...that idea is much more of a shot in the dark because coils are not cheap and generally you cannot return them once used, but they can act wierd...plus AFAIK there are two types of old ignition coils resistor and nonresistor... and don't believe they're interchangeable. You might also do the old fashioned pull one plug wire at a time till you find one that does 'not' make a difference in idle...otherwise I'd be back to fuel as others have suggested...could have fired up okay after a sit and then quickly progressed to a flooding condition...have you checked the plugs for excess carbon/fuel during testing...checking the fuel flow rate on the pump is pretty straight forward for a stocker (1 pint per 30secs IIRC) might be time to try a substitute carb to eliminate the fuel system. That's all I got at the moment....Good luck!

EDIT:

This will wind up being something stupid simple and I will freely admit it

Totally agree with you there...Occam's Razor....and understand how it can be to avoid that tunnel vision, hang in there you'll find it (playing mr. obvious here) but always good to pull back and take a break as well....many times the sollution or possible solution comes to me when I'm not conciously thinking about it.

 

[Explorer]

The carb has given me problems in the past. Took three teardowns to get it working to start with. But has been doing well for last six months. I can't see anything wrong with carb or adapter plate. Shot some Seafoam down the airhorn/tube, cranked a little and filled it back up with Seafoam. I'll let her sit overnite and see what happens. I can see a diff with idle mix screw. Closed it won't even try to start. Plugs dirty up fast, but dry. The coil I used is a new one off my 302 Bronco with DSII that runs perfect so I know thats good. Even put it back on the 302 to make sure it didn't smoke it. I'll call in the morning to see if I can pickup another good carb(not holding my breath). Checked the condenser it's fine. It almost "has" to be heat related or carb is loading up the engine. It was the coolest morning I've had all week, and the first it's run right. Appreciate the help guy's, it will not beat me.

 

[bmbm40]

Just curious- what carb is on there? If nothing at the yard maybe Napa or Craigs List. I put an add on CL a few years ago wanting a 250 and not expecting a response and got two calls within two days and one of those motors is in my Bronco now. Some one close by may have swapped a six for an eight close to you.

 

[Explorer]

It's the stock 66 Autolite 1100 SCV carb. Since I updated the dizzy to the 68 with centrifical advance I'll try to find a non SCV 1100 carb. 68-69 had the smaller 170 carb (1.10 venturi/156 cfm) but no SCV and should do fine for this application. Same throttle bore. Blasted 1V carbs cost almost as much as a 4V.

 

[69.5Mav]

Explorer

Two things stick out for me, both of which I have had trouble with in the past.

One, a condenser can read good on a checker and even be good for a little while then go bad as it heats up. Just to be sure change it, theyre cheap.

Two, a plugged fuel system can look ok for a short while then stop flowing. I would prime the carb with a half cup of fuel and if it starts and runs consistantly on that fuel then dies when it runs out or even continues to run until stopped and sitting over night you could have a marginal fuel pump that won't deliver enough fuel to start the car at low cranking RPM but once running works well enough to run the car.

 

[Explorer]

Did the condenser routine, I can see fuel squirt when accelerator is moved. Pulled the carb again this morning after trying to start and fuel is puddled in intake. Too much fuel if anything. Needed to change exhaust manifold gasket anyway, so pulled that off and checked good for any cracks in intake. Mustang junkyard, got no answer so left message, but no return call yet. Put an ad in another forum looking for a carb. Think I'll post in the classifieds on here. Somebody should have a carb laying around. Don't like how the vacuum line is run to tranny so going to rework that while I'm waiting, eliminate another potential leak. Nice thing about being retired, got plenty of time. Son's not happy with no car, but thats life. Need to fix this so I can get back on my own project. Pertronics did replace my defective reluctor, much better design, may stick it back in once it's running. Appreciate all the ideas, more minds=more ideas.

 

[MustangSix]

Long shot, but look at the fuel pickup in the tank.

They get clogged, fall off, collapse, whatever, and fuel won't flow properly. They don't need to be completely clogged, just too much restriction. The pump will eventually fill the bowl, but can't keep up, so the engine dies off then won't restart until a little more fuel can seep into the pump and eventually fill it. It's run for a while, then die. The pump might even be able to fill the bowl enough that the accel pump will squirt, but not enough to keep the car running. Sometimes the problem gets compounded by the same crap clogging the filter.

As a test, the next time it quits, run a line from a gas can to the pump inlet and see if it restarts. If it does, you found the issue.

 

[Explorer]

5psi fuel pressure, clear filter at carb stays full.

 

[69.5Mav]

You could try disconnecting the fuel line and plugging it and see if that helps to start and run the car until the carb is dry.

 

[Explorer]

Fingers crossed! Got up and did a few things that really needed done anyway. Reworked vac line to tranny, disabled SCV circuit on carb. New plugs(only 6 months old), new wires, still no improvement. Been awhile since I fooled with points. All my books said point gap is .026 or .027 depending on year. V8's listed .017 or .021. Regapped to .019 and she fired right up. Set timing, idle mix, even hooked up vacuum advance to manifold vacuum and let it idle for an hour. It'll have to start again in the morning before I venture out for a test drive. Tired of loading it on the trailer to get it home. But, first time it's actually started and run in a week. Wish me luck.

 

[JackFish]

Perhaps the balancer has slipped?

 

[Explorer]

Timing marks come up perfect. How would slipped balancer effect point gap?

 

[69.5Mav]

All my books said point gap is .026 or .027 depending on year. V8's listed .017 or .021. Regapped to .019 and she fired right up

DOH!

Thats where my book says to set mine on the 170. My chev 235 L6 wanted .015 to .016. At .026 youre gap was to big and the coil wasnt getting enough points closed time to charge the magnetic field.

 

[Explorer]

Remember I said it would be something stupidly simple?

 

[JackFish]

Timing marks come up perfect. How would slipped balancer effect point gap?

Oh never mind I need to read better, I see you got 'er going. Way to go!

 

[bubba22349]

If the distributor has a lot of ware in upper bushing or shaft than the point setting is going to change as the rev go up. Also I would only use a dwell setting is a much more accurate way.

 

[Explorer]

It's a "new" rebuilt dizzy, while that means nothing with today's quality standards, it seems tight. My dwell meter, seriously have to look for it. Haven't seen it since I quit working on VW's about six years ago. With another frame off build and spare parts, engines, tranny's setting around, the garage is a mess. I'll get the Mustang out for a road test later this morning.

 

[Explorer]

Had her out a couple times today and all is well. Actually running really well, getting rid of the old Load-a-Matic seems to have helped the response. Even found my dwell meter today, now if I can find the right dwell setting for it. Thanks for the help guy's.

 

[ludwig]

Actually running really well, getting rid of the old Load-a-Matic seems to have helped the response. Even found my dwell meter today, now if I can find the right dwell setting for it.

Sounds like a country song played backwards: you get a girl, the dog comes back, you get drunk and get married.