Bajawfo

This is a tough one ! Carb has gas in bowl at level glass, accelerator pump works, fuel shut-off solenoid is working, but not getting gas to venturi ..? Truck had started being longer and longer to start. Didnt see gas in carb so figured fuel was running back to tank, installed an electric fuel pump. Still took a while to start. Now I cant get gas to squirt out into venturi at all.
Fixing truck up for my daughter .

KryptoRoxx

Maybe a clogged vent line in the gas tank? Seems like you're trying to pull fuel but there's a vaccum in the tank.

gmack192

Check the sock on your fuel pickup... (inside the tank)

slow-mo

Well I'm assuming that you have a stock Toyota (Aisan) carburetor? If so...

it will be difficult to physically squirt fuel out from the venturi main nozzle. Squirting is characteristic of a brief flow of fuel, the way that the Accelerator Pump works. The fuel coming out of the primary barrel main nozzle will flow once appropriate engine speed is reached. As engine speed is increased, air flow will then increase through the venturi, which will then perform its function. Low pressure is created in the venturi and the relative high atmospheric pressure in the float bowl will then push out the fuel. So the fuel doesn't necessarily squirt out as the fuel will flow out.

So, you may be using "squirting" in such a way that I am misunderstanding what you mean, or what was once squirting is not actually coming from the venturi, but a supplemental jet.



Once fuel has been pumped in the float bowl, the fuel is physically impossible to flow back into the fuel tank. Here's a picture to show what I mean. The fuel is physically seperated from the port that feeds fuel into the carburetor bowl.





So, installing the electric pump would have no affect on changing the presence of fuel in the bowl.

Bajawfo

Now your reply's remind me that there is a rush of air when I remove the gas cap. I got the squirt thing from another thread (here). It said when you open the throttle you should see fuel 'squirt' from tiny tube on left side of carb. If fuel doesn't come out of there, shouldnt I at least see fuel inside the carb ?
btw this is the best forum. You guys rock !

slow-mo

On my 1987 22R, that's normal.


What that may be is the Accelerator Pump jet. When operating the throttle, fuel will squirt out of this jet shown in this picture.






Yes, however, if there is no fuel in the float bowl, then the manual Accelerator Pump in the carburetor has no fuel to squirt into the carburetor. So fuel needs to be in the float bowl first for fuel to squirt into the carb.

Bajawfo

Thats what is so hard to understand, there is fuel in the bowl. Fuel filters never had dirt in them. Sounds like a tear down of the top of the carb is next...?

slow-mo

Wait...are you saying that even with fuel in the float bowl, when you operate the throttle, no fuel squirts into the primary barrel?

Bajawfo

Thats exactly it.

KryptoRoxx

That's what I would do. Or you could use it as an excuse for buying a weber

Beamed from my dumbphone

slow-mo

OK, from you description it sounds like the manual Accelerator Pump rubber diaphragm has failed (a tear in the rubber diaphragm). It is fairly common. The pump is in this picture:





I say manually controlled because it is controlled by an arm connected to the throttle valve.





Be aware that you also have an Auxiliary Acceleration Pump (AAP) located on the opposite side of the main pump, this can also fail (a tear in the rubber diaphragm):





The main pump diaphragm is easy enough to replace, unscrew the 4 screws and swap out the diaphragm.

The main pump works all the time. The Auxiliary Acceleration Pump, when working properly, only works on a cold engine (cold engine coolant). Once the coolant reaches a designated temperature, the thermo-sensor shuts off that vacuum that controls the AAP.

Bajawfo

I took the top of the carb off today and found the manual Accelerator Pump passage (tube) was clogged. It took some time to clear it. Black dirt in bowl too. Runs ok now. Still a little long to start though. Thanx for your help guys !!

slow-mo

That willl do it as well.

I'd say replace your fuel filter.


What's common with these carburetors is that the fuel will drain out of the float bowl into the intake manifold. Then in the morning, the engine needs to turn over longer just to pump fuel into the bowl first before there's any fuel to squirt into the carburetor by pumping the gas pedal.

Bajawfo

Just wanted to add. Truck wouldnt start again so I took the carb off and bought a rebuild kit. 1st thing I noticed was how dirty everything was. Cleaned the out side then tore it down. Found accelerator pump tube clogged again. But the main thing I found was one of those tiny (F$%King) vacuum tubes was cracked almost in half ! Put new tube(s) on and put carb back together .....Seems to be starting and running a LOT better ! And yes a Weber is in its future.

slow-mo

Did you replace your fuel filter? Or does it even have one?

Bajawfo

It had the original type filter, I had changed that too even though it looked clean. but it now has an inline filter right in front of the electric fuel pump.