Looses rpm's @ WOT

jopes

Petty Officer 1st Class
Joined
Oct 19, 2008
Messages
288
It has done this ever since I bought the boat. Run @ WOT for a few miles then it will drop 200-300 rpm's. It doesn't do it at slower planing speeds.

-Original Qjet leaked fuel on the throttle shaft so I replaced it with a Marine Edelbrock 600 CFM.
-Vent hose has been replaced so I know it is not blocking any air flow into tank.
-New fuel / water separator filter makes no difference.
-Just replaced the ignition system with a delco voyager
-New fuel pump
-it Runs about 120-140 degrees, so it is not a over heating issue.

None of these items have fixed the issue of loosing those RPM's @ WOT. If I keep it about 3000-3800 I could run out of fuel with no loss of RPM's.

I did notice when I changed the fuel pump, I had no fuel come from any of the hoses. But every time I change the fuel / water separator it is full of fuel.


At this point I am thinking something with the fuel tank is causing a blockage for fuel to the engine.


Any one have any ideas?

1988, 350
 
Last edited:

jopes

Petty Officer 1st Class
Joined
Oct 19, 2008
Messages
288
The good about the tank?

-It is not the anti syphon valve, because it doesn't have one.
-It is not the pickup tube since it was all metal.

The bad. When I removed the pickup tube from the tank it totally ripped out all the threads to put another one back in. So 3/4 of a tank of fuel left and I need to get some new threads in the tank. The tank is Aluminum so I think I will be able to put a tap in there and recut more threads in it so I can thread a new pickup in.

I guess I will replace the 2 ft of fuel hose when I put this all back together. After that I have no clue where to go if that 2 ft of hose is not the issue.
 
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