TheSamba.com :: View topic - Fuel Pressure and Dual Kads--dead head from pump

Sat Jul 26, 2014 12:32 pm

Ok, so I feel a little stupid posting this and I hope that I already have my answer, but im posting here for a little guidance.

I have dual Kads on a dual port 1641, engine has 10k on it maybe, got the kads 2 years ago from kaddieshack.

Did a tune up a week ago and the fuel pump went. Replaced the fuel pump and now I'm trying to take a fuel pressure measure. Bought an actron fuel pressure gauge and "dead head'ed" the fuel pump with the gauge. I got the pump to read 1.75 psi. Hooked up to the dual kads, and eventually, they lost fuel pressure.

Now my thought is this; pressure dead headed from the pump should be 3.5 psi so that 1.75 psi goes to each carb.....

Is this thinking correct?

I dont have extra line to splice into one of the carbs, so im stuck dead heading the pump.

Any help is appreciated.
Thanks.

Sat Jul 26, 2014 1:58 pm

um, unless you're having some kind of problem with either fuel delivery or excessive pressure getting past your needles and seats causing an operational issue, you're thinking waaaay too far into this.

Sat Jul 26, 2014 2:46 pm

aidssss wrote: Now my thought is this; pressure dead headed from the pump should be 3.5 psi so that 1.75 psi goes to each carb.....

Is this thinking correct?
Not so much. Pressure is not additive. ;-)

If you measured 1.75 psi just dead-headed with the pump then that is what your "3.5 psi" pump is putting out. You didn't mention using a regulator so I assume you are not using one. How did you "get the pump to read 1.75 psi"?

Also, how did you determine that the kads were loosing pressure?

Max

Sat Jul 26, 2014 3:37 pm

Brian71 wrote: um, unless you're having some kind of problem with either fuel delivery or excessive pressure getting past your needles and seats causing an operational issue, you're thinking waaaay too far into this.

yeah I agree!

I have ABSOLUTLEY NO IDEA what my fuel pressure is. I don't need to know. I just turn the key and drive...

Sat Jul 26, 2014 6:08 pm

You will never get a accurate fuel pressure reading the way you are doing it.
You need to get more fuel hose and a tee so you can see what actual fuel pressure is with engine running.
You could have a block in the system (like a plugged fuel tank screen) and never know it the way you are trying to check.

Mon Jul 28, 2014 8:10 am

teed it in. got the pressure dialed in using the gaskets and push rod shaving. Thanks for you help