i inherited my dads 86 4x4, while driving the other day it shut off and acted like it flooded out. After pulling the air filter housing and tinkering with the throttle linkage I was able to git it to crank. Drove about 100 yards and it did it again. After several cycles of this it finally got me home. I was not able to get back to it for several days but walking by i noticed the smell of gas. I finally got back to it yesterday and got it running. It had rough idle and finally stalled. I pulled the air filter cover and found/heard fuel leaking in the carb. i started looking and could see the fuel leaking bubbling in on the right side barrel ( when standing at the front of the truck). I was able to determine that pulling the hose off the MC Valve made it stop leaking. It was hard to crank and would then idle rough with the line disconnected. Hooked the line up and it would stall and you could here the full leaking. Unplugged the hose and left it for the night.

Back at it again this morning, plugged the hose in and it ran fine. Drove around the yard does fine for about 3 min then stalls out. Walk around front and hear the fuel leaking again.

Does this mean the MC valve is bad or it there something else causing this. Thanks in advance. Attached pic for what I am thinking is the MC Valve and hose i am pulling off.

 

First things first. Did you make sure you have fresh gas, clean enough tank, and a new fuel filter? It sounds like the needle valve is sticking causing the bowl to over fill. Look at the site glass on the front. The fuel should be between the 2 notches.

To test the MC valve, start the truck, remove the vacuum, and then put your finger over the inlet (white plastic side) of the MC valve. You should feel nothing being pulled through and it should stall.

 

i have put a new filter on the truck. fuel is fresh but i am not sure how clean the tank is. i will check the site glass and the mc valve. tks

 

I checked the site glass before cranking and it was in the center.. Started the engine, it bubbled and filled up. truck ran fine and idled great. checked the MC valve by removing the hose and felt nothing over the white inlet and noting happened. put me finger over the metal piece the hose came off of and the idle picked up. Put it all back together and hit the gas it idled down to normal and then drove it around and all seemed fine, if i understand correctly the fuel should stay between the notches? What would you suggest next? Thanks

 

It sounds like your float level is too high or there may be some trash stuck in the needle seat or it may just be stuck if it's filling the bowl while running. Try tapping on the back of the carburetor and running some fuel cleaner of your choice through. It may dislodge or loosen the valve seat.

If that doesn't work, your stuck removing the air horn (the top of the carburetor) to get to the float and needle seat. At that point, you might as well buy a kit and rebuild it completely.

 

ok, thanks