Powerboat Forums at SpeedWake banner
1 - 7 of 7 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
Hi all, it's my first post and it's a head scratcher for me. For starters it a 26 ft. flat bottom Alaskan Riverboat with a 460 ford V8 and a Hamilton Jet. The engine is new as of last year and has never had any serious problems in the 10 years we have run the vessel. Last week the fuel pump gave out, so we replaced it with a brand new Carter electric pump, and new fuel lines and pressure tested the system at 6-7 psi.

Now the boat is apparently starving out and/or surging a bit between 3200 and 3300 rpms under heavy load. We changed the carb with the same result. Added a new fuel filter and made it worse. the mechanic thinks it's related to harmonic vibration or pressure causing cavitation in the fuel pump itself.

any thoughts?
 

·
Registered
Joined
·
1,900 Posts
Put in a mechanical fuel presure gauge between the pump and the carb - best money you can spend....you will see if it is fuel or not right away.

I had a wierd fuel issue that I battled for months until we had a gauge....then - with all the facts -CFM figured the problem out for me.

Oh and check fuel vent for spider webs or mud wasps
 

·
Registered
Joined
·
478 Posts
Yep. Install a mechanical gauge that you can read while running along... confirm that the issue is definitely fuel related.
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #7 ·
we installed a guage between the pump and carb, reads 5-7 psi from both tanks. the problem persists with the fuel caps off, so i am pretty sure it's not vent related. the reason i think this is harmonic or vibration based is that the problem dis-appears at 3450 rpm. this has to be something simple. we couldn't narrow it down with a timing light. we are going to use a new hose and a gas can today to check if the fuel line has a manufacturing defect.
 
1 - 7 of 7 Posts
Top