I have a good battery, brand new starter, and solenoid. After running the truck for 10-15mi i shut it off and it turns over really slow. Then fires up? Fires right up no problem when cold? Where should i start?

 

Back the timing off 2*. It's to far advanced. Is my guess.

 

Where is the starter from? I had same exact issue. Got mine rebuilt at reputable shop and it took care of problem. I never buy an over the counter parts store starter. Agree could be the timing as mentioned. Also make sure the vacuum advance plate in distributor is returning to home position when no vacuum.

 

johnr6,

Yes, the prior suggestion to back off the timing is a good one. If that does not do the trick you may want to look for a so-so electrical connection. Heat increases resistance and a connection that works when cold may not be quite good enough when warmed up. Whenever I have an electrical issue I always clean the battery terminals first. (and make sure they are tight) It does not cost anything and it is quick. Since your battery and solenoid are new, it could be that one of those connections are not quite tight. While you are at it, you may want to check the battery ground as well. Lastly, the starter itself is grounded as it mates up to the bellhousing. Usually not a problem but you could run a separate ground strap from one of the starter mounting bolts to the frame for added grounding. (Probably not needed.)

 

So I have a similar issue after messing with my idle/timing/vacuum/mixture screws -

1. If I set the timing so that the vacuum is JUST in the "normal" range than I have the same problem johnr6 is having.
2. If I set the timing based on the highest vacuum reading I get the hard start problem AND pinging.
3. If I back off of the timing until just before it starts getting rough than no issue with starting or pinging but my vacuum reading is in the red.

Now saying all of this I was thinking my starter was getting hot since the headers run next to it but if engine set to #3 above it starts every time without issue.

 

Could be alot of things mentioned above, the only thing i can swear to is getting rid of the tired monster OEM size starter and replacing with a mini high torque, the thing is amazing. Half the size and could care less what the temp is.

 

Do you have headers?

 

No headers. Im going to try adjusting the time and bought a heat sheild to wrap the starter. And see how that works. Thanks everybody

 

My mechanical fuel pump will let gas flow all the way back to the tank. It takes some cranking to get gas back to the engine. A check valve fixes the problem. Don't know if this is what is happening to you, but might be worth checking.

 

Clean your battery contacts and cables.. get'em nice n shiny then apply petroleum jelly on the assembly to seal out airborne contaminants.

 

Another possibility not mentioned is the distributor might be getting weak....

Engine was not mentioned, however if it is an FE....they can be real finicky and not start at all when the engine is hot until it cools down then starts right up as there is not a problem...

That is what I went thru with my 390 in 2014, the counterweight springs were weak as this syndrome gave me no warning - all of a sudden it just happened while vacationing in northern Canada with my camper (took me a day to figure out).

I would grab the rotor (top of distributor shaft) and rotate it as far counter clockwise as possible and let go to see if it snaps back with authority or just limps back to it's position (checking strength of the counterweight springs)...if this is the diagnosis of a weak distributor, replace the springs or distributor.

Since the engine does start but slow when warm or hot, I think it's just a timing issue as noted - and I would also check if the timing chain is worn or loose by grabbing the fan blade or place a socket on the crank bolt and check for slack.

All my Fords have Milodon true double roller sets as the chains don't stretch.