Will NOT start hot.

[timc930]

63 IIa. I have replaced the following:

1) New 1BBL Carb from Host
2) Elect Fuel Pump
3) Plugs
4) Cap
5) Wires
6) Points
7) New Coil

If I just sit, and let the truck idle for approx 15 minutes, then shut it down 1) It will restart if I try with less than a minutes time elapsed since shutting down, but if I wait say more than 3-5 minutes the truck will not restart. I disconnect the fuel line from the carb, run the pump, plenty of gas comes out, but I let it run for about a minute just to get cool gas thru the lines, then reconnect. Still will not start. I don't think I have a vapor lock, as I get plenty of fuel out the line when disconnected.

1) Is is possible that the exhaust manifold is getting the intake manifold to hot, thereby vaporizing the fuel as it comes into the intake? The reason I am asking is that if I our a bit of fuel into the intake, it bubbles like it is boiling. I have not changed the manifold configurations, and the gasket is between the intake and exhaust, just thought I'd ask this. It seems fuel related, as it will immed retire if I try to start within a minute of shutting it down, I just don't know where the issue is, as again, I seem to have plenty of fuel pressure.

2) Once the truck cools down it fires right up.

Ongoing Problem!!!!

[o2batsea]

Has it done this from the moment you installed the new carb or has it just been getting worse over time or did it just start doing this?
I agree that it seems to be fuel-delivery related.

[timc930]

No, I had this problem last summer as well, added the above parts over winter to try and resolve. Been fighting this problem for a while now. Runs fine in winter though!

tim

[swbseries]

Even though you have a new coil, it could be defective. Try to putting the old one back to see if it solves the issue.

[slowmo]

It does seem fuel related. I know the hot start procedure for air cooled aircraft engines involves delivering more fuel during the start sequence. Have you tried choking during a hot start? Sounds at first counter intuitive but it does fit into your hypothesis 1).

[ArlowCT]

Testing for spark at the plugs when hot may help prove that it is a fuel problem. If you don’t have a spark tester grab one at the parts store and give it a shot.

Is there a spacer between the carb and the intake? Often I have seen plastic spacers fit to reduce the heat transfer to the carb. Also, where did you mount the fuel pump? The fuel today is very different than it was years ago and has a big effect on timing and carb settings. I have found setting them by the book is useless now and do all of my tuning by ear. I’ll be interested to find out what the issue is.

[timc930]

Fuel pump is mounted on inside of pass fender. No plastic between manifolds, just the oem gasket, and I just replaced two weeks ago. Agree on testing spark at the plugs, actually my next step, as you say, will show fuel or spark as the problem. I'll mess with it more this week.

[ArlowCT]

No plastic between manifolds, just the oem gasket, and I just replaced two weeks ago.

Sorry, I may not have been too clear on the spacer. The ones I have seen were between the carb and the intake acting as a barrier for heat.

I have been running an electric fuel pump for years and only with the last one was I able to completely get rid of my vapor lock issues during the summer. I mounted this one to the frame rail right next to the gas tank, I have access to it through the center cover in the seat box. This puts the fuel pump where they work best. Turns out these pumps hate to pull fuel but will push it all day long (plus pulling a vacuum on the fuel will reduce the boiling point even further), I guess this is why so many electric fuel pumps are found in the gas tank. It may prove to be worthwhile moving your pumps location and always carry a spare. I've had a few crap out with no warning.

[timc930]

SO I may have found my problem, still checking it out, but i wanted to post what I have found so far. I got the truck hot so that it would not start. I took the coil off and put it in the freezer to cool to off, put it back on the truck and it fired right up. This is the second "new" coil, as I bought the first one from O'Reilly's, then just to rule it out when I started having the problem, I took it back and exchanged it. So, either the coil is positioned in a bad place, or the O'Reilly coils are not adequate for the heat generated in the Series engine bay.

Where is the coil supposed to be mounted out of curiosity???

tim

[triumphtr7guy]

In your case Tim, sounds like in a freezer unit. chuckle chuckle
Not unusual to have stuff fail right out of the box, some brands several times.
firewall is the place for mounting, and if you have to repostion it, keep in mind accessability. Did that with my TR7, was way down on the firewall and moved it up so I dould clip leads to the coil without electrocuting myself by touching something.
Good Luck,

Bruce

80 TR7
73 Series III

[timc930]

with the car idling, and the coil laying on top of the air filter away from the heat of the engine, the coil get's so hot you can't hold it. Is this normal? Again, this is the second new coil (Borg Warner) that I've had. It's a 12V coil with no external resistance required.


tim

[LaneRover]

I have heard that there can be 'issues' when using a 'hot' coil with points. But it could just be that they tend to go through points. not sure if your Borg Warner coil is considered a 'hot coil' or not.

[timc930]

So I think I am just going to get the Pertronix D176600 Dist and their Coil and be done with the Ign issues/concerns and move on to other issues...

[slowmo]

The next time it is hot and won't start I would first remove the fuel line and see if the carb is getting gas. If so I would then yank spark plug #1 and do the spark test. I am not sure you have identified the problem yet. Fuel or spark?

It could be that the delay when you popsicled the coil allowed the engine to cool enough to start up?!

[timc930]

The next time it is hot and won't start I would first remove the fuel line and see if the carb is getting gas. If so I would then yank spark plug #1 and do the spark test. I am not sure you have identified the problem yet. Fuel or spark?

It could be that the delay when you popsicled the coil allowed the engine to cool enough to start up?!

When hot and will not start I have done the following:

1) Removed fuel line from carb, placed line in jug and run pump. Fuel flows and fills up the jug.

2) Removed air cleaner and activated throttle linkage and watched the fuel spray down the throttle body of carb.

3) Attached timing light to number one plug wire, cranked engine, no strobe. When car does crank, the strobe flashes while cranking.

4) Removed coil, put in freezer to cool it off, installed on the truck and it cranked right up. Usually it takes an hour or so for the truck/coil to cool down to fire.

[SafeAirOne]

3) Attached timing light to number one plug wire, cranked engine, no strobe. When car does crank, the strobe flashes while cranking.


Huh? :confused::confused:

[timc930]

Ordered the Pertronix Dist and Coil today. Hopefully this is the end.

tim

[timc930]

Installed the Pertronix Dist and Coil, took all of 15 minutes. Truck fired right up after install, let it idle for 30min or so while I set the timing and cleaned up, shut it off, waited around 10 to allow for the heat soak, and it fired right up. Did this several more times after driving, let it sit and idle, shut it off, wait 5, then fire it up. So far no problems.

Just to be safe, I am going to relocate the elect pump to under the pass side seat, and wrap the fuel line in insulation. Hopefully after all of this I am good to go again.

tim

[Opabob]

After replacing plugs and wires, after adding an electric fuel pump, and adding a fuel return line, the hot starting problem in my case continued to deteriorate to the point where it would just die after idling for 15 minutes. So, at this point it became easier to diagnose. Spark check confirmed the coil was indeed dying as it heated up. I added in the ballast that came with the new coil on the assumption that the old Lucas coil being replaced had an internal ballast so it would probably do no harm. So far the truck is running better and there is no trouble with hot starts now. I still notice some hesitation going through the gears after a hot start, and idle is stumbling a little. I should have checked spark from the get go, but I was not wild about fumbling around under the hood in the middle of traffic, and I usually drive alone any way. A bonus is that the tachometer now works. I'm thinking the tachometer jumping around is a possible diagnostic tool if it is wired to the coil...