Lou C
Supreme Mariner
- Joined
- Nov 10, 2002
- Messages
- 13,864
Also there are other things that can cause fuel delivery problems, such as a fuel pick up tube with a clogged filter, or a blocked/corroded anti siphon valve.
I rigged this up to test mine for leaks, both were fine, my performance problems were simply from bad gas this past season. I tested it to -10" of mercury which is what a mechanical fuel pump pulls usually. I found that a good anti siphon valve opens between -1-->2" of mercury
The way to rule these causes out is simply hook up an outboard fuel tank to the fuel pump and run the boat on that. If you still have problems, it's definitely the carb, but if it runs perfect it's the boat fuel system. So, you'll be pulling the fuel pick up tube and looking at the anti siphon valve.
When I did that, the boat leaped up on plane and ran perfect. Shoulda done that before going through the points and cleaning/rebuilding the Quadrajet!
PS if you do this it's a good idea to put a shut off valve on it, in case the fuel line to the pump leaks! Use good clamps too!
I rigged this up to test mine for leaks, both were fine, my performance problems were simply from bad gas this past season. I tested it to -10" of mercury which is what a mechanical fuel pump pulls usually. I found that a good anti siphon valve opens between -1-->2" of mercury
The way to rule these causes out is simply hook up an outboard fuel tank to the fuel pump and run the boat on that. If you still have problems, it's definitely the carb, but if it runs perfect it's the boat fuel system. So, you'll be pulling the fuel pick up tube and looking at the anti siphon valve.
When I did that, the boat leaped up on plane and ran perfect. Shoulda done that before going through the points and cleaning/rebuilding the Quadrajet!
PS if you do this it's a good idea to put a shut off valve on it, in case the fuel line to the pump leaks! Use good clamps too!