Motor won’t stay running

[413]

Good thought. And good question.



OP says it will run for 30 seconds but maybe that's with the key in start?

He said it runs for a few seconds and dies. Total run time is 30 seconds.

The coil is not overheating in a few seconds, it will run quite a while with 12 volts to it.


Now then I'm going with a vacuum leak. Look over the intake runners and make sure all vacuum ports are plugged.

 

[AJ/FormS]

( I haven’t timed it yet. )

Well that's probably it then, not because the timing is wrong but because with too much timing, the throttle has to be closed to not have a high idle, and when you close the throttle, that shuts off or at least reduces the amount of Transfer-slot fuel dispensation.
My guess is that an extra turn of the curb-idle screw will get you in the ball-park. If the idle speed is too high, just retard the timing until she is happy.

If you take the carb off, reset the transfer slot exposure to between dead square and a lil taller than wide..... then leave it there! adjust Idle-speed with timing.

 

[Dana67Dart]

The coil is not overheating in a few seconds, it will run quite a while with 12 volts to it

I agree but if the coil is full volted for 5 minutes before the start attempts and the points are closed, maybe.


But I agree it is most likely a fuel delivery issue.

 

[harrisonm]

I have a few thoughts:
1. I am not trying to be rude, but when you completely rule out something, in this instance the carb, you can chase your tail forever looking for other problems only to eventually find that it is the carb. I have learned that the hard way! I am NOT saying it is the carb, I am just saying not to rule it out at this stage. It's like losing your keys and saying, "They couldn't possibly be in the garage, so I won't even look there. Then, two days later, you fine them in the garage. Oh yes, I remember now. My phone rang and I set my keys down so I could dig my phone out of my pocket!
2. You said the carb worked fine on another 400 big block 3 weeks ago. Perhaps something got jostled or tweaked between engines. Perhaps the idle adjustment for one engine isn't working well on the other. Perhaps a float is sticking. Who knows, but I would not rule out the carb yet. You've got several very knowledgeable guys suggesting that it could be the problem. Try this; crank the mechanical engine idle speed screw (the one on the linkage, not the idle mixture screws) in so that when the engine starts, it will run at way above an idle speed. That should help bypass the idle circuit.
3. Get someone to help you by dribbling some gas down the carb when it starts. If it keeps running then but not on it's own, I would lean towards carb, fuel pump or a partially clogged fuel filter.
4. It is not on an actual Engine run stand, so perhaps something is not hooked up properly? My friend Mark, the guy with the Studebaker Power Hawk, has an actual engine run stand. We have had several engines on it. It sounds to me like your setup is not working well for you if you can't even get it started and then shoot some gas down the cab before it dies.
5. Bad timing could be your culprit. That would be tops on my list.
6. A vacuum leak will ABSOLUTELY allow an engine to start and run but NOT idle. But that will be hard to check if you can't get the engine to stay running.
7. You might have to install the engine to figure this out. That way, everything can be hooked up properly, and you should be able to figure the problem out easier.

 

[Inertia]

Base gskt mismatch, vacuum leak, plug all vacuum fittings on carb, particularly PCV hose fitting .

 

[Bewy]

If the carb was run with E fuel.....
E fuel is hygroscopic, absorbs water. If the carb was left to sit for awhile, you would lilely get corrosion in the fuel bowls...& blocking the idle jets.

 

[Kendog 170]

 

[Dartswinger70]

Stand there and spray carb cleaner in the air horn it while its running in squirts...if it stays running its the carb...or some sort of fuel delivery issue...sometimes troubleshooting is a simple as that...

 

[Dana67Dart]

Stand there and spray carb cleaner in the air horn it while its running in squirts...if it stays running its the carb...or some sort of fuel delivery issue...sometimes troubleshooting is a simple as that...

see post 5 then post 6, I guess its not that simple, but it is! (and yes I'm busting the chops of the OP)

 

[Dartswinger70]

see post 5 then post 6, I guess its not that simple, but it is! (and yes I'm busting the chops of the OP)

Yup...that points you in a direction anyway I uses to use the carb cleaner trick on towed in no starts to just figure if it was spark or fuel related.

 

[moparhunter]

Thanks to all the replies. I really do appreciate it. I haven’t had a chance to get back to the motor yet but will later on the week and will update my findings . Once again, thank you very much to everybody that is replied. I appreciate the support and advice .