Need a little help with JEEP motor

[72 Blaze]

Hey guys I need a little help with my JEEP. I know its not a CHEVY, but I thought y'all could help me find the problem. Its a 1978 Cj7 304 stock 2 barrel carb and intake. Only thing not stock really is headers, side pipes, and small parts.... Here's the problem, the Jeep starts up great and runs great. When it gets hot it takes for ever to start back. Almost like it was flooding out... Took the carb off cleaned and rebuilt.. Still runs great but it takes for ever to restart after she warms up. Also after warm up she starts to smoke. Lets just say if I'm sitting at a stop light I'm killing bugs! She clears up fine when you are driving down the road. It doesn't smell sweet, and doesnt do it when it's first started up.. I'm sure she needs rings and stuff... But it's just crazy that other than the smoke and hard start up after it gets warm, the Jeep runs really well.. I replaced the coil.. Anything I could check?

 

[oregon k5]

smoke is likely valve guides worn out slowly leaking oil into cylinders, once driving it burns out until you idle again, as for hot start problems... does it crank over easy and not start or does it barley crank over like its "tight"

 

[Richcz28]

You may be getting some vapor lock when restarting when it's warmed up. Fuel in the line can vaporize with heat and it takes a few cranks to clear out.

What color is the smoke?

 

[1BEATK5]

X2 on the color of smoke.

Also, have you checked the timing?

 

[Big Ray]

My old Cj had a 304...it would:

Vapor lock

the starter would heat soak...especially with headers...

and it had a knack of burning up the rear exhaust valves...


good times

 

[elks]

i would check your fuel line positions and location of filter. It sounds like a vapor lock issue. the filter set up on most jeeps is prone to having temp issues. They are easy to get to, but are usually only inches from the heads. Also you might check fuels pressure, I found one time that low fuel pressure was not keeping fresh/cool gas running to carb, it was coming in slow and gaining too much heat, when dumped into hot carb its higher initial temp was allowing for vaporization. i have had it happen on a few jeeps that the fuel lines in were picking up too much and as a result had to reroute a bit and it was fixed.

 

[Big Ray]

i would check your fuel line positions and location of filter. It sounds like a vapor lock issue. the filter set up on most jeeps is prone to having temp issues. They are easy to get to, but are usually only inches from the heads. Also you might check fuels pressure, I found one time that low fuel pressure was not keeping fresh/cool gas running to carb, it was coming in slow and gaining too much heat, when dumped into hot carb its higher initial temp was allowing for vaporization. i have had it happen on a few jeeps that the fuel lines in were picking up too much and as a result had to reroute a bit and it was fixed.

^^^this

I put a small electric fuel pump on mine and rerouted the filter...worked like a champ. I put the electric pump in line with the mechanical pump.

 

[72 Blaze]

Thanks! It's a turn over, turn over, turn over, and then when it cranks it smokes almost like it has raw fuel building up.. Like its flooded out. It's not really a timing issue where its hard to start like a drag... Its crazy! I have never had a bit of trouble with her before and I have owned her for around 20yrs! I drove her all through high school! I know she needs to be rebuilt, but the cranking thing is driving me nuts.. I trying to fix that if I can first.. Then drive her for a while longer before I have to rebuild her.. She really does run good!

 

[diesel4me]

The carb may be getting hot enough to boil the gas in the bowl after you shut it down hot,and it'll flood and drown the spark plugs,then you'll have to crank it a long time to get them cleared up enough to fire and the smoke you see is probably unburned fuel....a thick heat insulator gasket under the carb may help if thats the cause...

 

[Big Ray]

well, it takes fuel, air, & spark to run...need to find which one is missing...

pull a wire & check for spark...?

 

[magik235]

Have you checked to make sure the choke is opening fully when it is warm?

 

[72 Blaze]

I have checked the choke. I hope to work on it this weekend. Thanks for the help with this. Sometimes even after its warm I have to hit the gas to get it to idle down when I come to a stop light. It's weird.... I was thinking it may be in the choke as well....

 

[72 Blaze]

Should my fuel be sucking back into the carb when the jeep is off? Ok I have a glass fuel housing. When u turn the jeep off I can see the fuel drain back UP in the carb... That's why I betting it hard to start back... Like its flooding out. Or should it be doing that, is that normal? To be honest I don't how it flows up hill with motor shut down...