Holley repair

[1954bmw]

In the Media Gallery Images there were some pictures of a Holley carb with a message "what size is this carb ?". I am having problems with Holley carbs running very rich. Replaced the original Quadrajunks with Holley replacements and found out the fuel pump was bad, too much pressure. First problem was the new carbs hit the thermostat housing, so you put spacers under the carb and one runs great, and one runs very rich. played with power valves and jets and nothing. Swapped carbs and problem went with the carb, replaced that carb with a new one and it runs very rich, What I need to know is there a place that can check these out and run them on a test stand to figure out what I'm doing wrong????? Thanks

 

[Jimway]

Jimway speaks Holley. Perhaps I can translate.

 

[1954bmw]

Ok, I have had a little luck with Holley's, that was why I replaced the Quadrajunks. I purchased two of the 0-80552, 4175 650 cfm marine universal replacement carbs. I have checked float levels and even plugged the power valve, always too rich. In desperation I even purchased a third carb and tried that, nuttin, too rich. Even swapped carbs from left to right and problem followed the carb. These are on a 1989 Bayliner 3888 with twin 270 horse small block Chevies. I'm open to any suggestions.

 

[Jimway]

I'm up to my elbows in modular Ford at the moment. I believe that the carbs you have are spread bore direct replacements for the Quadraflush. Verify that both engines are in time and match, have properly functioning ignition, properly functioning matching exhaust, same fuel pressure at carb inlet, same spacer plates installed the same way. One backfire can ruin the power valve. They make a backfire valve for retrofit. Low vacuum at idle will trigger power valve, that's why we have to match them to engine idle vacuum. Were these replacements new or second hand? I'm probably telling you stuff you already know but we have to start out somewhere.

 

[Jimway]

Some additional thoughts: 1/2 turn open on idle speed from closed. 1 to 1 1/2 open from lightly seated on idle mixture. Check secondary idle speed screw, as it should be adjusted per manufacturers instructions. A 65 power valve should be good from 12 inches of manifold vacuum and up but if you are lower than that you may have to go to a 45 or 35. 3/8 fuel lines at a minimum. 5psi fuel pressure at a minimum but do not exceed 7 1/2 psi. Fuel pressures above 7 1/2 will create big time fuel control problems. If manifold vacuum at idle is 12 or below, take the reading and divide it by two and that will be the power valve size. I've been chasing a coolant leak in Mrs. Jims f 150 and hoping it's not a head gasket situation.

 

[Jimway]

Finally found a crack in the intake manifold ( too much boost??!! ) on Mrs. Jims truck, got a new one on the way. Are you rich at idle or under way or all the time. Do your spacers have matching openings for the butterflys. Holley recommends the #3406 1 inch spacer. Also don't connect electric choke to ignition wiring. If you block off the power valve you have to upsize the jets by a factor of 8 but it will run rich as all get out in a cruise.

 

[1954bmw]

Runs rich all the time, you can actually see the smoke when it is idling at the dock. Also ran so rich, it discolored the oil, I changed it mid season. Where would someone find the 3406 spacer??? Do you mean the spacer has four holes instead of one large??

 

[Jimway]

Mr. Gasket makes the spacer specified by Holley. Yes it has individual holes per butterfly. I hit up my local ORiellys and they have it, 38
bucks, comes with studs and gaskets.