I have a 55 merc 292 rebuilt with a holley 4 barrel, pertronics in dist, electric fuel pump. When I drive on the highway at crusing speed the engine stumbles and dies, but after coasting a little it will fire up again but will run terrible. any thoughts I am getting very frustrated.

Mine was acting somewhat like that, it turned out to be a bad power valve, caused a flooding and would die. Gary

       

Gary, 55 Vicky, St. Germain, Wisconsin

 

Sounds fuel related to me. Filters good? How about the sock in the tank? Hows the fuel pump? Thats where I would start.

Dan      Kingman Az.      86409

If the carb has a viton float needle, the alcohol in the gas has softened it, and it can stick in the seat and shut off the fuel.  When it finally drops out, the car will run again.

John - "The Hoosier Hurricane"

Sounds a lot like vapor lock. Easy check is to install a clear piece of hose between the fuel pump and the carburetor (check for leaks). Run the car till the problem occurs and then look for bubbles in the fuel line.



Mike

Rimrock AZ

1956 Fairlane

1956 Fairlane Victoria (ORREO)

 

Overlooking Beautiful Rimrock AZ

Next time it quits, pull the fuel cap off. You could have a stopped up vent line. It sounds like you aren't getting fuel. However, a bad coil can go dead when they are hot and work when they cool off.

Kenneth

Fredricksburg, Texas

All are good suggestions.  My vote goes for a fuel delivery issue.  Fuel pump, sediment in the lines, fuel pump vent, sucking air at the fuel pump inlet, or a problem within the tank itself are all possibilities.  My own ’55 gave me a similar problem for about 30K miles and finally tracked it down to a crack in the steel fuel line in the gas tank itself.  My particular problem would only show up when the tank was half full or less and was resonably random in nature.  Might show up only once in a month or might do it twice in a single day.  Once I found the problem, simply replaced the fuel tank and haven’t had a problem since.

Lorena, Texas (South of Waco)

Talk about Murphy's Law??!  How did you go about verifying that problem, especially when it defies common logic where steel is "presumed" to be OK and rubber is suspicious?  Just curious.

My dads 51 acted like that and even though the gas tank had been cleaned the pick up tube was forgotten about and was clogged up,cleaned it out and no problems again

Butchering up everything I can get my hands on in Dayton Ohio