Need Rochester 2jet help.

[Farm Shpp]

I bought my 70' c10 about a year ago and ever since I've had it the truck floods when I shut it off.

The truck has the original 307 with a Napa reman Rochester 2gv. It's a California emissions truck but most of that has been bypassed or removed.

When I look down into the carb after I shut the truck off it takes about 5 seconds and then gas starts to drip from the nozzles inside the venturi. It doesn't drip alot, but just enough to flood the crap out of my little 307. Every time I hot start it i have to hold my foot to the floor and crank it for 5-10 seconds before it will clear out and fire.

I've tried everything I can think of and the problem still persists. Here is a list of what I've tried.

-rebuilt the carb with a kit from Mike's carb parts. This included a new float and needle and seat.

-installed a new fuel pump to make sure it was the correct low pressure pump for a 307

-pulled apart the carb to double check my float height again.

-adjusted accelerator pump and divorced choke settings to factory spec.

-installed an aluminum heat shield and fiber insulator block to make sure it wasn't heat soaking.

I'm really out of ideas and any help would be greatly appreciated!!! Thanks!

[geezer#99]

Put a fuel regulator on it that's rated no higher than 5.5 psi.

[1969c10joe]

my two cents wont get you a bazooka joe bubble gum but if it only does it when the engine is hot then your fuel is getting heated up.Try running engine a just long enough to warm it up with hood open if your carb doesnt flood then you found problem good luck

[Farm Shpp]

Originally Posted by geezer#99

Put a fuel regulator on it that's rated no higher than 5.5 psi.

Thanks for the reply. I've always assumed that the float valve wasnt holding the leftover pressure from the pump when I shut the truck off.

The only puzzling thing is when I pull the top off the carb after I shut the truck off the bowl isn't overfilled? That would make me think the valve is holding correct??

[Farm Shpp]

Originally Posted by 1969c10joe

my two cents wont get you a bazooka joe bubble gum but if it only does it when the engine is hot then your fuel is getting heated up.Try running engine a just long enough to warm it up with hood open if your carb doesnt flood then you found problem good luck

Thanks for the advice. I'll run it for a couple minutes tonight with the hood up and report my findings! I thought the aluminum heat shield and insulator block would keep the carb from getting heated, but I've heard that 2jets can be really sensitive to heat....

[1969c10joe]

you mention that it takes five seconds for the fuel to start dripping i am guessing that heat is causing fuel to expand and then the pressure rises it couldbe the fuel line is getting hot you might have to reroute fuel line (and or filter) and or insulate the fuel line

[geezer#99]

Originally Posted by Farm Shpp

Thanks for the reply. I've always assumed that the float valve wasnt holding the leftover pressure from the pump when I shut the truck off.

The only puzzling thing is when I pull the top off the carb after I shut the truck off the bowl isn't overfilled? That would make me think the valve is holding correct??

Lower the float level 1/4 inch and see what happens.

[Wrenchbender Ret]

Check the fuel pressure & install a regulator if it is above 5. If the passage ways under the carb & in the manifold are clear, you might try blocking them off. It may be getting excess heat to the bottom off the carb. I have 3 of them on my 56 & it never floods.

[Troy Sr]

Is the vent tube clear, if not the pressure build up from heating up could pressurize the float bowl.

[Farm Shpp]

Originally Posted by Troy Sr

Is the vent tube clear, if not the pressure build up from heating up could pressurize the float bowl.

When I had the top of the carb off I noticed there was a passageway from the top of the bowl to somewhere near where the air cleaner mounts. It was free and clear so I think I'm good there.

[Farm Shpp]

Originally Posted by 1969c10joe

you mention that it takes five seconds for the fuel to start dripping i am guessing that heat is causing fuel to expand and then the pressure rises it couldbe the fuel line is getting hot you might have to reroute fuel line (and or filter) and or insulate the fuel line

The line from my pump is steel and runs up between the front of the motor and the lower radiator and heater hose. I'll try and make a new line to get it away from the engine heat and stick an inline regulator in it as well as people have mentioned.

I'll try that and see where that gets me! Thanks!

[Farm Shpp]

Originally Posted by geezer#99

Lower the float level 1/4 inch and see what happens.

I set my float level to the "California" spec listed on the sheet I got with the carb kit which was a little lower than normal of course. And when I pull the carb top off there really isn't much gas in the bowl, so I don't think the bowl is overfilling.

Is there an external bowl overflow on one of these carbs? I'm used to messing with motorcycle carbs. And on those the gas runs on the floor if the bowl overfills haha.

[MikeyMan]

Could an incorrect gas cap or fuel tank venting be a possible contributor to this issue?

[Bluegrain64]

It's the volatility of ethanol blended fuel. If you can or maybe you are? Try non-oxygenated fuel. If your running the good fuel then look at getting a regulator.