v6 cold start problem

67 V6, won't start cold in morning without pouring gas in carb. Runs and starts perfectly rest of day. Next morning, no go. PO put in new oem carb. Carb adjusted, timing set, runs great, just won't start in morning without shot of gas. Then starts instantly.

 

Re: v6 cold srart problem

Have you been using the choke? If so, check this. Next time before trying to start first thing remove the air filter and operate the throttle while looking down the carb. Should see two nice even streams of gas from the accelerator pump (one per bore). If not then the fuel could be evaporating or bleeding back through the fuel pump. A weak fuel pump could be the culprit and should be tested.

 

Re: v6 cold srart problem

Check all above. Also could be leaking through carb. Check your oil to make sure it does not have gas in it.

 

Re: v6 cold srart problem

Choke checked out and is working. I pump the gas, don't pump, use full choke, a little choke, no choke. Pedal held on floor. Nothing.

Pour in gas, starts right up. Rest of day, starts right up. Carb must be going dry overnight.

Slow responding, out driving around. Great June day in NE.

 

Re: v6 cold srart problem

You didn't answer the question about the action of the accelerator pump? If this is not working, you would run the battery down and still not start. Look down the throat of the carb and open the throttle fully. You should see two full steady streams of gas, one per venturi. If you don't have it then it won't start cold. Without it, it will start every time warm or hot.

 

Re: v6 cold srart problem

Will check this tomorrow. Thnaks.

 

Re: v6 cold srart problem

Nice Jeep!

 

I had a similar problem. I suspected there was no gas in the carb so I pulled the top off the carb to check the float bowl and it was empty. Don't know where the gas was going but it cured itself before I figured it out. The problem only lasted for a week or two. It was summer not winter in my case.

Like the others have said, you need to check the accelerator pump but note that if it isn't squirting it might be because there's no gas - not because it's a bad accel pump.

 

Accelerator pump working. Had friend watch this morning, no start, no squirt. Prime carb with gas, starts right up and accelerator pump works fine.

Overnight, the float bowl is going dry, where the gas is going I have no idea. Going to replace filter at carb (maybe check valve not working?) Maybe inline filter? Fuel pump supposedly fairly new. Don't know why pump doesn't fill carb when cranking engine.

Seem to be narrowing it down, though.

 

Do you have an inline filter between tank and pump? Junk from tank can hold the flapper valve inside the pump open or slightly open causing low pressure and drain-back to tank. Remove line at carb and blow compressed air from line at bottom of tank. Install a clear filter between pump and carb so you can see fuel action to the carb. The fuel should be visible in the filter after you shut down, for at least a week-end and the pump should hold a residual pressure of about 2lb. The fuel in the float-bowl can only drain out through the lead plugs in the bottom of the carb unless it has a crack in it somewhere.

 

Again I would recommend checking your oil. Does it smell like gas, is it over full? That may be where your gas is going if the carb is leaking into the manifold and down the cylinders. Maybe someone else knows if the fuel pump can leak into the crank/pan area if the internal seals go bad.

 

On the '70 CJ5 I recently acquired, I had the same problem, tossed a new fuel pump in it, and it's been good since.... Just my $0.02

 

Yes it can. I've seen them bad enough to actually raise the oil level

 

Anyone have a diagram of how the fuel lines should run. Mine comes out of tank into glass bowl, into filte,r into pump and up to carb. Vapor line comes out of pump back to tank. Is the filter in the right spot or should it be between the pump and carb? Should the filter have two lines into and out of, one being vapor back to tank. My filter has only one line into and out of.

 

Bump

 

The rest of the story. Finally took the carb apart which PO said was OEM new. Well, it was in tough shape. Put on a new (not rebuilt) carb and solved problems. Starts great.

 

Glad you finally got it.