1 month ago I purchased a 1976 Holmes Horizon Jet Boat. It has a 460ci. engine and berkley jet drive. Before I put it in the water I had to rebuild the carb. When I put it in the water it did not run very well. I checked the cap & rotor & I checked the plugs for proper gap. It ran a little better but when I punch it it boggs and dies. It then takes a bit for it to run again. It idles perfectly & has no misses. I since have tried a new fuel pump and replaced the carb with a known working carb and it still does the same thing. I take it out run it at 3000 to 4000 rpm and it runs great, as soon as I punch it, it will take off and then bogg and die. Is my coil giving me problems or maybe my distributor or the ballist resistor? It has a marine points distributor. I'm a small time mecahnic and this thing has me baffled. It never skips a beat until I punch it. After that it starts hard and boogs at low rpm. after waiting for a minute or 2 it starts right up and runs great until I punch it. Any help would be much apreciated.

The carb that came with the boat is the original 0-80318-1 600 CFM Four Barrel Marine Carburetor,  Model 4160; Electric Choke; Vacuum Secondary; Calibrated for Big Block Block 460 Ford Marine Engines. The second one I borrowed from a friend off of his performance street car is a Holly 650 double pumper. I just do not think it is carb problem. Maybe I'm vapor locking. My fuel tank is vented. 

I may be wrong here but how about your fuel filter... carb could be just on the edge of running lean and when you open it up it basically runs out of fuel... you did say it did it even with a known properly operating carb... Hows the fuel pressure.. Did you say you have a fuel pressure guage...   ... I'm really thinking filter or worn out pump... Just my op.. good luck

Sounds very similar to the problem I have been having with one of my boats. I think Rivertard Identified it this past weekend as the "cow whisperer" heard a mssive vacuum leak at speed from the carb base/throttle plate gaskets. I'll break out the WD40 tomorrow when I'm off. There's a whole thread on resolving this fiasco over here.

http://www.socaljetboats.com/engine-mechanical-electrical/electric-fuel-pump-issues-10004/

Ray

Well, I replaced the fuel filter by the tank, even though it was only 2 weeks old, & I had much improvment today. Its not perfect, but much better. Next I'm going to replace all the fuel line and I'm going to run 2 new upgraded fuel filters. Wish me luck. I have my fingers crossed. Thanks for everyones help.

Did you pull the plugs to see what they look like?   I agree with checking the points to.
The plugs may just tell you all you need to know though.

might want to check the distributor manufacturer

i think mallory is .18-.22