Vacuum advance/distributor causing issues?

[Chyrio]

I've been trying to track down this wierd issue with my g63b. It's got a 32/36 weber installed and tuned. Timing is set to 7-8° btdc. So the issue is the truck will start no problem when it's cold. Choke is working and it will fire right up. And it will drive with no issues. The idle will steadily increase by about 100-200rpm as the truck warms up. But if you turn the truck off when it's hot it usually will not start up right away again. It will just turn over and act like it's gonna start. Sometimes it will start and idle then you touch the gas and it dies. Then magically after constantly trying to start it/getting out and checking things for 5-10 minutes it will start up and act like there isn't an issue until you turn it off again. Yesterday I got curious and unplugged the vacuum advance and the truck started right up. Then died again. So I hooked the VA up again and then it started and ran fine until I turned it off again and then same issue. Anything else to check before I buy a new dizzy?

[85Ram50]

I have had a similar issue I have been blaming on heat. I have gone to a giant sized spacer 14mm if I remember correctly, for the Weber.
That seems to help it but it will still increase the idle unless a rev it at a stop when it is hot outside. Seems like in winter it doesn't get hot enough to do this. I have anew dizzy and coil and it has done this since then. In fact I died at a lumber yard and iot took forever to get it going again. That is what motivated me to get the larger spacer. I have a 180 Stant Thermostat I have been thinking about going to 160.

[Chyrio]

Ooo you know... Come to think of it. I still have the thermostat from Alaska ha ha so definitely the 180. But why would that change how the engine starts once its warm?

[85Ram50]

Some thermostats for this vehicle are 192.
IDK why. I'm good at stuff not so much with the theory. On mine I was thinking that the intake got so hot it was heating the Weber carb up so much it was making parts of it expand and those parts affected how it ran. I'm thinking it would be the linkage where the throttle cable connects and or some internal moving part. It eventually started that last time in the lumber yard when we poured gas into the carb directly. It took a few tries but it finally worked. I drove home without stopping. It ran fine the next day when it was cooler and gave me no problems.

[Chyrio]

Hmm. Mine has had this issue since I moved here. I guess it would be really easy to swap the thermostat and see if that fixes the issue. Other than that I'll look into the deeper adaptor for the weber carb... Do our trucks even need a VA? Can I just remove it to see if that's the issue?

[geezer101]

Next time either of you guys have this issue, try releasing the gas cap on the tank. If it's hot enough, you might be experiencing vapour lock. I don't think it's an ignition problem IMO. Seeming this is happening and the only real other common denominator you have is the G63B engine, maybe there's a coolant flow issue with the intake manifold? The flow through them is somewhat restricted, they have a habit of collecting chunks of debris from the block inside of them and are known to corrode out through the underside where the coolant basin is. The stock spacer gaskets are barely .25" thick and they don't exhibit the heat soak phenomenon BUT there might be some merit in the theory behind thermostat operating temps...

[85Ram50]

I did not mention it but geezer reminded me I did open the gas cap during the attempts to restart at the lumber yard. There was no audible release of pressure.

[Chyrio]

Hmm. I'll try the gas cap thing. Didn't think of that. And I'll take my chances with a 10 dollar thermostat and gasket if that doesn't work ��*♂️

[Chyrio]

Okay... Pulling gas cap did nothing. I've also noticed the truck has to sit for atleast 5 minutes for this issue to happen. Turning it off to go get something from the gas station or something it will start right up. But last night it did it to me again. So I got out and manually set the choke while it was warm and it started right up no issue. So maybe I have the fast idle or something not set right? I know how to set the choke right for the electric choke which I have done but how do you tune in the fast idle?

[85Ram50]

How did you set the choke? More open or more closed? I assume you had someone turn the key for you?

[Chyrio]

No I just pulled the throttle and set the butterfly valves then released the throttle. And I followed the recommended setting. Where it's like "loose". Where you can easily push it but still maintains rigidity

[85Ram50]

OK, I don't quite understand how that would work, but sure I know mine didn't like to start when the choke was holding the butterfly to closed so I would prop it open and start then go.

[geezer101]

The choke should open with the lightest amount of effort when cold. Like the weight of the choke butterfly is enough to make it droop a tiny bit. It will probably need fine adjusting depending on weather (full winter/peak summer)

[Chyrio]

I mean... The choke works fine though? When the truck is cold it starts up everytime with no effort usually the first turn of the key. The choke shouldn't be engaged when the truck is hot right?

[geezer101]

You're right - the choke shouldn't engage once the engine is hot. The chokes in these things are a metal heating coil running off the ignition circuit. If the choke has a ton of tension on it from the get go, it won't take much of a temperature drop for it to want to start closing again. My hypothesis - it will tolerate it in cold weather due to intake air temps being low and the air is more dense but in hot weather, it wants to lean out due to air intake restrictions from the choke wanting to close up (meh, I'm only taking a wild guess at this one - hopefully you're not chasing smoke)

[Chyrio]

Hmm. I mean when I take the intake cover off it's always fully open. But not while someone is turning it over? I guess maybe the coil could be trying to close it? I'll have my buddy turn it over while I watch

[camoit]

also make sure the choke is not closing to tight when cold. It only takes a floppy choke to fire up.
You can also change the exciter on the dist. It's a little plastic thing on the side with 2 screws. When they start to fail they will get hot and quit. Or just fail all together.

[Chyrio]

O gotta check the choke. But the exciter is like brand new. I replaced it like 6k ago.

[jldavis1969]

The issue sounds like hot soak to me. I have the same issue if I leave my D50 more than 10-15 minutes then try to start it. Carb too hot, Gas boils into the intake runners and floods the engine. Try this when it happens again, Hold the throttle down like you have flooded it and then crank it. will take 2 - 3 tries at wide open to clear the excess fuel.

[Chyrio]

Sweet! I'll give it a try tomorrow! Thanks for the advice jldavis1969!

[Chyrio]

Hmm. Might try one of these too https://www.google.com/url?sa=t&sour...iQoAPHB2ZG7DiZ

[Chyrio]

Also... Come to think of it when my Fuel pressure gauge worked it was reading like 3.5 to 4 psi... Recently I started slightly leaking fuel out of the regulator. I wonder if I need to dial the pressure down a little bit.

[xboxrox]

DUH..? Me not you...

Does my Mikuni have an exciter or is that a Weber part; I'm excited to know..?

DUH..? Me not you...

Chyrio, you in Alaska (?) and the truck warms up (?) possible I guess with global warming (?) I am planning an electric fan modification

DUH..? Me not you...

Hot engine when symptom occurs (?) Fix, check or modify things that will ensure the engine runs cooler (?) I been using the 50/50 premix stuff...

Good Luck & Wishing you Happiness while fixing your truck -- George

[Chyrio]

Chyrio, you in Alaska (?) and the truck warms up (?) possible I guess with global warming (?) I am planning an electric fan modification

I haven't update my profile. I moved to Phoenix in April! It made it all the way here overloaded by 600lbs
20190406_151248_HDR.jpg

[xboxrox]

Your truck has neat accessories camping anything & proves small don't mean weak... Arizona like Hawaii = no snow down low... Perhaps if not already done, you might consider an electric fan mod of some sort in order to achieve lower temps under the hood..? One YouTube video DON'T DO IT ABOUT ELECTRIC FANS IS WORTH WATCHING