'96 Prostar 205 LT1 Engine Power Loss

[isaacdroster]

I purchased a 96 Prostar 205 in March and it has ran great through the summer up until this past weekend. When I go wide open throttle, the boat planes out and run good for about 10 seconds and then the engine starts to lose power, but only for a split second at a time and then its back to running like it should. It does this about every 5 seconds in an irregular pattern. Eventually the engine will kick into what I believe is safe mode and wont go over 2100RPM's until I shut the engine off, and fire it back up. The check engine light has not come on yet.

So far I have
-replaced all the spark plugs
-replaced the fuel filter
-cleaned the fuel pump intake screen
-cleaned the battery terminals
-cleaned the engine ground
-cleaned the plug wires
-put a can of seafoam in the fuel tank
-checked to make sure tank was venting properly
-checked fuel pressure at idle (38 psi)
-checked fuel pressure when the boat goes into safe mode (about 44 psi)
-IACV was replaced at the beginning of the summer

I'm thinking about ordering new plug wires, and crank positioning sensors just to rule those out. Anything else I should try? I can't get the boat into a shop for a couple weeks and don't mind spending some money troubleshooting if it gets me back on the water sooner.

Thanks!

[mikeg205]

check to see that fuel pickup not letting air in.. if the pickup has not been changed or refurbished - it's sucking air...

[isaacdroster]

Hey Mike how should I go about doing this? Pull the fuel pickup tube out of the tank and check it for cracks/leaks?

[mikeg205]

yes.. this is the top of the fuel pickup - leaked air at 1psi.. get new nylon tubing and hi-tack sealant - and use a spring clamp.. you'll have to cut the ends of spring clamp to get to fit back into tank cover..

[jakethebt]

Also of note, there are two fuel filters. One on top of the tank and a canister one on the back of the engine.

[isaacdroster]

Thanks for the replies, I'll check both of these after work tomorrow.

[mikeg205]

I would also check fuel regulator - 20 years.. might be good check... or just replace - the cross reference part is in the library dropbox under general discussion..

[mikeg205]

Also check the screen at the base of fuel pump.. its inside the inlet of fuel pump.. note the close off the fuel valve at tank and pinch fuel line - pump does not have power to suck gas from tank if hose drains.. if it does you will have to prime it.

[isaacdroster]

There are two hoses coming off of the fuel tank, are both of them suppose to have pickup tubes going into the fuel tank?

[Val]

What is this "safe mode" mentioned below?


1996 ProStar 205 LT1

[Table Rocker]

There are two hoses coming off of the fuel tank, are both of them suppose to have pickup tubes going into the fuel tank?

No, one of them is the return.

[isaacdroster]

I checked the fuel pickup tube and everything seemed okay, I blew through it with a finger closing one end and did not feel any leaks. Also pulled the fuel line out to check it for leaks and found nothing. I did not see a fuel filter on top of the tank, I'm guessing it was removed at one point in time. I cleaned the fuel pump screen the first time around so there is no problem there. Spark plug wires arrive tomorrow, and I will work on replacing the fuel pressure regulator.

[isaacdroster]

Boat Update: I took the boat for a test run today and noticed that when the boat would lose power, the voltage would drop off. Also noticed that the only time the problem occurs is when the boat is in rough water or hits a big wave. I took the boat into a bay and it ran perfect the entire time I was in calm waters. I'm guessing it has to be a loose electrical connection somewhere.

I'll start with the battery terminals, engine ground, and the positive cable going to the alternator. Anything else I should check? Battery, alternator? Thanks!

[Table Rocker]

Safety lanyard

[curver900]

If original battery cables that would be my next guess...