Hey folks, I have been doing all kinds of research and have tried multiple set ups but I keep getting the same outcome. The carb floods. I was told the carb I got came off a S1 car. I have a S2. My research is saying the car needs 4.5 PSI, I that floods the carb. I have adjusted floats to the spec in the manual. Have I been lead a stray with 4.5, should it be more around 3 PSI? Could my floats be bad? I tested them, they do float.

Thanks,
rkegley97

 

You adjusted your floats so they may be bad now. And the carb requires only 2.5psi. I don't know where the misinformation came from.

The float bowl vent solenoid also needs to be functioning to prevent floods.

 

Also a 0-15 psi gauge will be very inaccurate at the recommended psi and will report anything from 1 - 3 psi even if its at exactly 2.5 psi in reality.

 

My 1 to 15 gauge is that way. When it shows an indicated 2.5, the carbs like to flood a lot. When I turn the FPR down to just 2, the carbs don't flood anymore.

 

Ok, turned down the regulator, and re-adjusted floats. It still continued to flood. I replaced the Needle and Seats. Does not floor anymore. My guess is they where not the greats when I put them in last week with the rebuild kit. Luckily I ordered 2.

Now I just need to find that the base tune for the Nikki is with the idle and air mixture screw to see if I can keep the car alive.

 

Never use the new needle and seats in the rebuild kits unless the existing have major issues.

 

Keep the OEM seats but change out the needles if the OEM ones are old and hard at the viton tips (black rubber-like material). You must "burnish" the sides of the new needles on the back of a spoon before assembly of the little inner spring, brass pin and spring clip. The burnish polishes just the sharp edges so they glide up and down inside the OEM seats easier and are less likely to flood. Only do it until the brass gets shiny. You don't want to make them narrower and more likely to get crooked and bind, causing flooding.

 

i just did some testing with the fuel system, and here are my findings.

the stock pump with a holley regulator did 650cc of fuel in 30 seconds. pressure is 2.75psi, with 1/2 psi swings
stock pump with no regulator did 950cc in 30 seconds, pressure is rock steady at 2.75psi.

conclusion, holley regulator sucks, you are better off without it. it hurts flow, and doesn't regulate pressure

pump was changed to a Mallory 70 series. its got an internal regulator, and result is 1500cc in 30 seconds at 4psi. 4 psi is about as low as it will go though, we're not running a nikki

 

I agree about the terrible Holley FPR. I had to remove all of them due to leaking from the diaphragm and random flooding in the carbs (Edelbrock and Holley at the time).

These days I'll only run a Mallory 4309. When plumbed correctly, they will work with a Nikki at 2.5psi even though the 4309 was not designed to go that low. It is advertised as 3psi being its lowest setting but if plumbed according to their instructions, you can set it at as low as 1 to 1.5 psi.

 

Is that mallory an upright rotary vane type pump like the Carter 4070 or the Holley Reds? Is it noisy? What do you mean plumbed correctly, return line?

 

The 4309 is the pressure reg with a boost referenced port that can be used with blow through turbos like mine. And yes a return line at their recommended 3/8" going back to the tank is a must. The feed must be only 5/16".

Feed smaller
Return larger

This confused me at first until I understood what was going on.

 

the mallory is an upright pump, which sucks. after staring at it for a while though i bolted it to a piece of steel, and then bolted that to the car using the original rubber isolators, and its really quiet.

i've been meaning to post a drawing of the bracket, as it makes the thing a bolt in, but well i haven't. the car i did this with is also an 85, so i think the holes were for the GSL-SE fuel filter, and not sure if the 79-83 cars will have them.

after all this testing though, the stock pump is pretty good, pressure is rock steady and it flows enough for ~130-140hp says the back of the envelope