5.7L Carb Quandary

TenDriver

Cadet
Joined
Jul 5, 2014
Messages
6
After four separate carb rebuilds by three different mechanics, I have decided to ditch the factory two barrel and install a four barrel. The question us, which one? I have no experience with Rochester carbs, but it seems going that route may offer the best value as well as reliability. This is going on a Volvo 350. Current symptoms are hard to start when cold, low power, and then no start when hot. Plugs, wires, a rotor, cap, and fuel filter have had no impact. It still runs like garbage. And very rich. I haven't played with the jets yet, but think that's a list cause. It has also dieseled a couple of time (before this latest episode) leading me to believe there are other problems. In a nutshell, this boat has done this since an engine change a few years ago. My friend is getting close to pulling the drain plug and playing Taps while we put it out of his misery (not my boat, he just doesn't do message boards). Any advice on this carb? My hot ridding experience leads me to believe the little Holley on there just doesn't match the motor.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,258
by any chance is the clear tube from the fuel pump to the top of the carb full of fuel. if so, you have a bad fuel pump. The symptoms you describe are indicative of a ruptured diaphragm dumping fuel into the safety line and into the carb.

that "little Holley" as you call it will feed motors much bigger than you have. your motor running at 5100 RPM is only using about 430 cfm (0.85 VE for naturally aspirated)
 

TenDriver

Cadet
Joined
Jul 5, 2014
Messages
6
I haven't looked for any clear tube. I'll check.

Fuel pump makes a lot of sense. Are you talking engine drive, or (I'm assuming) electric?
 
Last edited:

TenDriver

Cadet
Joined
Jul 5, 2014
Messages
6
I looked this evening and found no clear tube from the fuel pump to the carb. The lines run from the tank, to the pump, to the filter, to the carb.
 
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