fuel or electrical

drem312

Petty Officer 1st Class
Joined
May 16, 2003
Messages
209
well here goes again,,, 1986 454 inboard rebuilt last year everything new ..i went to the boat today ran a temp gas tank inside the bilge with some carb/choke cleaner in it and fresh 93 gas ran engine for awhile also sprayed some cleaner ,,i did all this thinking my problem was gummed up carb from not using stablizer,,anyway engine sounded good,,hook main tank line back on go for a ride,,,15 minutes boat running smoothly 3500 rpm sounds good,, at half throttle,, i ran it steady for the 15 minutes,,cut throttle back engine starts to do the hesitation thing,,kinda pause or a skip thing,,2000-2500 rpm feel it skip turn boat around head back try open throttle,, should be 4200..goes up to 3500 can feel its not right then gets like an energy boost jumps to 4100 sound good smooth then very quickly goes back to 3500 for a few seconds jumps back and forth but mainly will not stay on the nice 4100 rpm side,,put another load of fresh gas in today,,fuel filter emptied and check several times plugs pulled looked ok cap and rotor looked ok inside,,if it was fuel problem why would it go well in the begining then act up,,if electrical where do i start??thunderbolt ingition,,the electrical box that is mounted on the riser can this go in and out???
 

foresteronw

Petty Officer 3rd Class
Joined
Oct 29, 2002
Messages
76
Re: fuel or electrical

I have a 1989 Sunbird Eurosport with a 5.7L and had some of the same problems last year. I would have some hesitation at low RPMs, the higher the RPMs the worse it got, and couldn't reach max rpm. I too thought it was a fuel problem. Come to find out I had the wrong size plug wires. I then ran it and it was a lot better but still a little messed up. After this I checked the points they were off, so I fixed them and the problem went away. It sounds like an electrical problem too me. Did you do a tune up? Try that, and check your points...if you still have them.
 

chris in va

Chief Petty Officer
Joined
May 4, 2003
Messages
410
Re: fuel or electrical

When I bought my 94 Caravelle 5.0, it would do the same thing you described. Hesitation, stalling, rough running etc. I think in my case the gas had been sitting around all winter and settled, along with the really bad cap and rotor condition.
 
Top