There are two hard fuel lines coming off of the carb... One is a "IN" and one is a "RETURN"...???? right..??? How do I differ which is which...??? I thought the smaller hard line was the return, but I brought my car to a local rotary specialist / shop and the guy told me the lines are incorrect or reversed..??? Yet I been driving the car this way for almost two months...????

Also the car falls on it's face at 5K-6K rpms in every gear at WOT and my air fuel guage drops deep into the lean..???

BTW: It's a Paul Yaw Nikki carb... I don't know what year though...??? If it matters.

Please help... ANY advice/comment is greatly appreciated...!!!!!

 

the small metal line is the fuel return line

the larger is the fuel feed line

the lines are irreversable, you cannot assemble the hardlines onto the carb backwards

 

The bigger diameter is the in, and the smaller is the return.

Make sure you're getting it enough fuel, and it not running out.

 

I know they are irreversable as far as the hard lines are concerned coming off the carb... but the soft fuel line coming off the nipple from my regulator is "NOW" switched with my soft return line going directly back to the tank (done by the mechanic I brought my car to) and the car still runs...????

Meaning the soft fuel line off the regulator, from the pump side, is on the small hard line off the carb...

And the return line / to dump fuel directly back into my gastank is now on the larger hard line from the carb....??????

I hope the mix up is causing the sputter.

thanks for the responses.

 

How old is the fuel filter?

 

Brand New Aeromotive.... I'll check it though...

The mechanic says the rod / assembly that actuates the secondaries is missing..??? I bought this carb off a reputable guy from the Mazspeed forum and the carb was redone by Paul Yaw..??? I don't see how this could be possible..??? Or how the person who sold it to me could of overlooked mentioning that to me since he really knows his stuff...???

I'm lost here and I'm trying not to pay an arm and a leg just to get my car able to be driven.

 

Well you got your answer. Your "expert" is an idiot, find a different shop and fast. Trying to supply the carb with fuel thru the return port will cause problems. While the line size looks adequate, the port that path flows thru down into the carb is puny. Its a drilled passage about 1/8". Look at the airhorn where the lines atach. On the top there is a brass blocking ball. That block the hole Mazda drilled to make the passage. Does anyone think that that puny passage can supply fuel to the entire engine? Not to mention that the fitting itself only has a port of similar size.

Oh and can you snap a pic of that part of the carb? If its indeed missing I can send you one. Easy to install too. However someone may have converted it to mech sceondaries and that may be why the link is missing. On the opposite end of that sec shaft look to see if the links are tied together or something like that. Sanp a pic of that too if you can. Just email it to me, Ill take care of you. I know Paul takes a bit of time to respond.

 

Thanks Carl... I will send pics tommorow.