I had something odd happen last weekend on my 78 F100 I need opinions on.

The electric choke does not work so I have always had to prime the carb with some starting fluid(rarely drive the truck) and usually after the first time it starts and runs for a moment it will continue to start on it's own without more spray. However this time I had to use the starting fluid numerous times before it would finally start on it's own. and one of the times it fired up it backfired through the carb hard enough to send the filter lid up to the hood of the truck....Regardless it finally stayed running and I took it up to get some gas and it ran great, no issues whatsoever...so I come home and grab my grandson for a drive and again all is fine and then we get stuck in some bad traffic for a car fire and the temp gauge goes up slightly(from the low line to the O in normal)...we get another mile down the road and all the sudden the truck bobbles and sputters and shuts off...I pull off the road and sit for 20 second and it fires right back up no problem....another mile and again same thing ...it did this 5 or 6 times before I finally got home....get home and let the truck sit while I am checking plug wires, etc..nothing out of place so after 15 minutes I start the truck up and drive it for a good 10 minutes with not one single hiccup or bobble and it sounded better than ever...so perplexed as can be I get back home and try to figure out WTF the story is...10 minutes later I take it out one more time and the temp was back up very very slightly like before..I get 1/4 mile down the road and start accelerating and again it starts doing the same crap as before.....so I just took it back home and said screw it for that day.

Sorry for the long story.....my question is does that sound like a carb issue(flooding maybe), or a timing issue?

On a possibly un-related note while checking things over I noticed the push down rod for the tranny is not hooked up and included the picture....I cannot for the life of me figure out where it hooks up to on the linkage because anywhere that makes sense, the rod doesn't reach to without the throttle being engaged

All help greatly appreciated

 

My first suspect would be the originl spark box if you still have it. Then possibly a clogged fuel filter or weak pump.

 

Same opinion. As far as the kick down rod, the carb appears to be from a manual transmission vehicle so does not have the extra linkage required to operate passing gear.

 

How would I tell if it is the original or not?

Also, would ti be wise to check the timing before spending money on a new ICM?

 

Is there a way to rig it to work, or am I just screwed? lol

 

yeah could be ignition related, like pickup coil, or ignition box, when it dies pull the coil wire and crank it through and look at spark. If it makes spark but no start, look at fuel. Remember that vapor lock is worse with winter fuel, the winter fuel is more prone to vaporizing than summer fuel on account that it is a diffferent formula. Fuel delivery or spark. I doubt flooding but maybe easy to tell, pinch fuel line off and crank it. Easy way to tell is carry a small can of gas and when she lays down on you, go and pour a LITTLE bit of gas down the carb, like a few table spoons and IMMEDIATELY crank it and if it starts then dies, obviously you have spark, so fuel is the issue.

 

yeah I thought of the fuel vs spark issue also...unfortunately though it starts and runs just fine until your down the road a ways

i did put 93 octane in it the same day this all started but that couldn’t affect it like this I am sure

 

What's said above are more likely causes, but my 73 did the exact same thing when I first got it and it was a rusty gas tank. When I pulled off the fuel filter and let it dry I could pour the rust out. It was entirely full of rust. Little pieces got through and gummed up the carburetor too.

 

honestly that could make a lot of sense....I hadn’t put gas in the truck in months and I put in a good 4-5 gallons....probably stirred a good amount of crap up

 

To eliminate the broke choke/starting fluid routine, I installed a manual choke which works better than the auto choke ever worked, as long as you know how to operate it. As far as the repeated stopping of the engine goes it could be either fuel or spark as the others have said. You'll have to do some checking to eliminate one or the other. Then you can narrow it down to find the culprit. I doubt that it's timing at fault, but it could be the module or something else in the circuit that intermittently interrupts the spark completely.
It could also be something fuel related; fuel pump; fuel filter; stopped up sock in the tank; cracked rubber fuel hose leaking air into the line, etc. Best wishes.

 

pdate on this

I installed a new fuel filter and replaced the ICM and sure enough the truck starts and runs much better now....BUT now I have a new problem. Apparently while trying to connect the new filter and line I put some pressure on one of the heater hoses(looks like maybe an overflow return to the water pump?) and the metal bib actually broke off inside the hose. I am hoping maybe someone can tell me which replacement I should get..looking online there appears to be many different sizes.

This is the pieces that I am referring to:

 

If it is the one to the left of the dizzy cap (#1?) I am thinking that looks to be the one threaded into the intake manifold. STOP do not try to remove it until you have put a ton of WD, PB blaster or acetone and trans fluid to loosen it up. If it is on the bottom of the pic (#2?), (#3?) then new water pump time. Unless I am looking at this really wrong.

 

Yes it is the #1..I intend to start PB blasting it today lol

Only thing is there are a good # of them listed online for this year truck with difference sizes..not sure which one i need

 

Exactly what motor you have in it?

 

the 302 2bbl