1978 Scout II with 392 Engine Problems - Off-Road Forums & Discussion Groups
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post #1 of (permalink) Old 08-06-2009, 05:07 PM Thread Starter
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1978 Scout II with 392 Engine Problems

I've got a 1978 Scout II with a 392 V8 engine that's giving me problems only after it gets to operating temperature.

The engine backfires, stumbles, and has very little power after the engine gets to operating temperature. Before it's warmed up it runs perfectly and has lots of power.

I've replaced the mechanical fuel pump and that didn't help. I then bypassed the mechanical fuel pump and used an electric fuel pump. That didn't help either. The fuel pressure is about 3 PSI when the engine is running no matter if the engine is cold or hot at full throttle, or idle.

The timing is good at 3 degrees btoc using the #8.

The carb (Edelbrock Performer 600 CFM, electric choke) was replaced before I owned the Scout, but it looks fine.

The distributor and coil were replaced.

Please help!!
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post #2 of (permalink) Old 08-10-2009, 06:46 PM
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I am having same problem with my 78 345, I think mine is a carb issue. I will let you know when I have rebuilt the carb. At idling mine is fine once I romp on it backfires and seems like it is flooded out.
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post #3 of (permalink) Old 09-15-2009, 09:16 PM
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my sons both had a couple of scouts. double check the corect timing, and check the timing chain/ they strech . when the motors cold so everything is tight. when things warm up they get loose and bounce. other thing is distibutor might be wore out
mike
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post #4 of (permalink) Old 09-23-2009, 08:12 PM
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Do you have the electronic ingition box checked?
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post #5 of (permalink) Old 09-24-2009, 04:17 PM
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Same Type of Problem Here

I seem to have the same problem with My 78 Scout. Engine idles and runs perfect until I've driven it for about 10 or so minutes.

My problem seems to be an O Ring that is located where the Shifting Arm enters the Transmission. There is a slight leak that, when seeps too much fluid, begins to make my Transmission slip. It almost seems as if the Carb is bad like TexasScout stated. I'll have to check my Carb too in order to double check everything.
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post #6 of (permalink) Old 02-23-2010, 11:22 AM
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392 engine problems

You probably need to get the carb rebuilt. It's either got clogged jets or some internal passages are clogged. The fact that it runs better when the choke is shut or partially shut (not yet up to temperature). It could also be a partially clogged fuel line. WHen the choke is shut it increases the vacuum within the carburetor helping is "suck" more fuel and restricting the air inlet. This richens the mixture and IH engines do love their gas.
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post #7 of (permalink) Old 05-05-2010, 12:42 PM
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Quote:
Originally Posted by texas sub View Post
my sons both had a couple of scouts. double check the corect timing, and check the timing chain/ they strech . when the motors cold so everything is tight. when things warm up they get loose and bounce. other thing is distibutor might be wore out
mike
Timing chain.. really... ummm.. lmao. The SV's don't have timing chains. 304 345 and 392 are all gear to gear. I don't know about the 4 cyls.

On the original problem, I don't care how long ford or IH have done it, it is ignorant to mount a coil on it's side. Stand the coil up. It's probably most of your problem. Take your hood off or a test run to see if you are boiling your fuel. For some reasom IH felt it was a good idea to trap the carb right up against the hood where no air moves, EVER.

If you have hose from the tank to the caarb, you probably have chunks of rubber acting as check valves too.
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