Hard to start when hot.

[N-Dually]

OK, Let me beat a dead horse, but I have tried to research this!

I have just completed a Weber 32/36 conversion. My truck starts right up in the morning and again when I leave work. It runs good, idles good, runs good, no flat spots or hesitations that I can tell. It idles a LITTLE rough in my opinion, but it may be the nature of the beast.

The problem... After I drive it and it warms up to normal temp, it sits for about 1-1.5 hours and then I am off again. At this point it is a bit hard to start. I have to give a bit of gas before it starts up. Once it starts, it runs fine. I know it is heat related. It only does this when hot. I just don't know how.

I have a fuel filter at the carb and the fuel pump. They are clear, fuel is in them, and I don't see any foaming.

I read that the Weber might need a float adjustment, but highly unlikely with a new one. I also read that what seems to be vapor lock might be the issue. It does get very hot under the hood. That you should run the fuel lines away from the engine. I have already done this. You can see it here:



Anyone have any advice? I am confused, simply because it seems to run so well in all other aspects.

Thank you!

[PEZi]

Define "a bit hard to start"

Mine does this all the time once it has sat a bit... but its because the fuel slowly flows back to the tank while it sits... takes a second or two to get it back up to the carb once you start it.

[synack7350]

same here. and for a notable difference in idling plugs, wires, cap, rotor, dizzy at full advance (disclaimer I don't have a light yet so I can't actually tell you how many degs btdc or atdc its running just sounds right), and coils! I'm bummed you had to go with that regulator....

[N-Dually]

Sounds like mine. I have actually watched the fuel go back into the tank a bit when I was troubleshooting the fuel pump wiring. When I say a bit, I mean like a second. Maybe not that long even.

BUT... Mine only does it when the engine is hot...

I messed with the timing a little yesterday. Just a little. No difference really, and I had a dreaded dead spot this morning... I put it back when I got to work.

Bummed because the regulator? Why? It gives me piece of mind and it makes sure I have the instructed psi.

[fastboatman29212]

IMO the "hard to start when hot" is not caused by the fuel running back to the tank. That IS probably the reason why my truck requires a couple extra cranks to start when cold, but it always starts immediately each time after that 1st start, even after several hours of sitting.

Dually - Please give us a few more details - does it cough and sputter (with hot starts)? If you get it started (hot) and then shut it off immediately, is it hard to start again?

[86 720]

My truck was doing the exact same thing when I first got it. Would be fine at first start up, after several errands, and at t the end of the day. However if I was driving for a while in between stops, than it would be hard to start or no start until it cooled down.

Culprit was the starter, even after several checks at the parts store. Finally I pulled the starter and bench tested it. Passed the first time and failed the next three times.

Take it out and bench test it at the auto store. Their hand held devices aren't accurate in my experience. Start is easy to remove and install.

You might want to replace those cables with 2ga. while your at it. Larger wire is better current flow with less resistance. I would replace at least the ground up to 2ga.

[N-Dually]

My truck was doing the exact same thing when I first got it. Would be fine at first start up, after several errands, and at t the end of the day. However if I was driving for a while in between stops, than it would be hard to start or no start until it cooled down.

Culprit was the starter, even after several checks at the parts store. Finally I pulled the starter and bench tested it. Passed the first time and failed the next three times.

Take it out and bench test it at the auto store. Their hand held devices aren't accurate in my experience. Start is easy to remove and install.

You might want to replace those cables with 2ga. while your at it. Larger wire is better current flow with less resistance. I would replace at least the ground up to 2ga.

Hey, thank you for your input! Interesting. Did yours turn over good? Mine does.

[fastboatman29212]

Culprit was the starter, even after several checks at the parts store. Finally I pulled the starter and bench tested it. Passed the first time and failed the next three times.

You might want to replace those cables with 2ga. while your at it. Larger wire is better current flow with less resistance. I would replace at least the ground up to 2ga.

I suppose that if the starter was "weak" it could cause it to not wanna start, but I sure would look for other causes first, especially if you get a good strong spin on the motor from the starter. Larger cables can only help, as he already pointed out.

One idea just came to me. Next time it's HOT, squirt a shot of starter fluid down the carb before you crank it. If she starts easy when you do that and hard when you don't, then you pretty much have a fuel/carb issue as the root of the problem, and not a starter.

Let us know. I'm very interested in knowing the solution.

[86 720]

Hey, thank you for your input! Interesting. Did yours turn over good? Mine does.

It does now! First crank every time. Had to replace a supposedly new starter, not reman..

[N-Dually]

Hey, thank you for your input! Interesting. Did yours turn over good? Mine does.

It does now! First crank every time. Had to replace a supposedly new starter, not reman..

Good, but what I meant was, when you had your old starter, did it turn the engine over freely? Mine turns it over easily.

Also @ FBB, Once started it runs good. No sputtering, stalling, etc. The only other problem that I have is that it occasionally diesels a little. I have adjusted the speed idle down to where it just touches the throttle linkage. As for the hard start after I turn it back off... It just hesitated for a split second. I restarted it 3 more times, and it fired right up with no problems at all. (Didn't diesel either, but that is very intermittent...)

I am thinking that something isn't quite adjusted correctly. Though I have a mechanical and electrical/computer background, my knowledge on carbs and timing is very limited. Actually this is the first time I have ever replaced a carb. At least she's running!

As for a buddy squirting starter fluid, I have none of either at the right time.

[fastboatman29212]

As for a buddy squirting starter fluid, I have none of either at the right time.

You don't need a buddy to squirt the starter fluid. Just pop the hood, take the air filter off and shoot a squirt or 2 down the throat of the carb. Then climb in the cab and crank it. Basically, you are just giving the motor a prime of fuel (just starter fluid instead of gasoline). People start old cars all the time by pouring some gasoline down the carb and they don't even have a fuel line hooked up. You could do that instead but you really don't wanna carry around a can of gasoline inside your truck. The spray can of starter fluid is WAY more convenient.

[N-Dually]

@ FBM,

I managed to squirt some starting fluid in to the carb as suggested. It did the same this. Perhaps it is vapor lock? Hmm...