2005 F90TLRD WOT problems

[Pbailey15]

New here and thanks for the forum......on to the issue.

While on the water last year we noticed a barely audible high pitched whine, we dont hear it anymore. Fished most the day and when we got back to the dock and tried to restart the battery was dead. We took it out the next day with a fully charged battery to check the charging. All was ok until the rectifier/regulator heated up, then it quit charging. The regulator was very hot and when I poured water over it to cool it down the charging came back. No problem, changed out the unit and charging is fine.

But at the same time this was getting figured out while running at WOT, the motor would start to break down. Pull back on the throttle and it would be good again for a bit. This has deteriorated to complete break down at WOT after about a half mile. If we let it idle for a bit, it'll go another half mile and so on.

Changed all the fuel filters and tried it on a clean six gallon tank with fresh fuel, no joy.

I'm not sure if it's fuel or related to the regulator going out.

Any suggestions for what to test and how would be appreciated.

Thanks

[99yam40]

Have you tested the alarm system?
Do you have gauges that will indicate any alarm and does anything show up when problem shows?

What do you mean by "complete break down at WOT"?

[Pbailey15]

Have you tested the alarm system?
Do you have gauges that will indicate any alarm and does anything show up when problem shows?

What do you mean by "complete break down at WOT"?

I have not tested the alarm system.
The controls have a buzzer or bell, but no gauges to indicate an alarm. I don't think it's over heating, as the discharge water is barely warm.

By complete break down I mean, loss of power, little backfires through the intake and the motor not firing, due to fuel or ignition issues. When I pull back on throttle to idle or just off idle, it'll catch again and run like all is normal up to 2000-2200 rpm, push it harder and it starts missing again.

Thanks for the reply.

[boats.net]

Pull the landyard cord and crank engine over buzzer should sound, need to check fuel pressure and vacumn to see if getting enough gas. May need new spark plugs and check to see if wires are correct.

[Pbailey15]

Pull the landyard cord and crank engine over buzzer should sound, need to check fuel pressure and vacumn to see if getting enough gas. May need new spark plugs and check to see if wires are correct.

Pulled lanyard and alarm sounded when turned over.

Is fuel pressure checked at shreader valve at top of vst tank? Where is vacuum checked?

Thanks

[Pbailey15]

I said a changed all the filters, but found one (strainer) inline between the low pressure fuel pump and vst. I pulled that one and couldn't blow through it. Ran some carb cleaner back through it and could then get some air to pass.

Cut it apart and there was a fine black residue on the screen. I'll replace this one and run the boat again. Are there any other filters in the fuel system other than the fuel filter before the low pressure pump, vst filter and the strainer?

I looked through the parts break down and didn't find any, but want to be sure there isn't a screen or filter I'm missing.


Thanks

[Pbailey15]

I picked up strainer part number 6C5-24251-00. I blew through this filter and there was very little resistance, almost blowing straight through. The one I pulled off was severely restricted.

I'll install and report, hope this is THE problem, if not, its definitely one of them.

[Pbailey15]

I replaced the strainer, changed the fuel line from the tank to outboard. The primer pump felt like the check valve wasn't working, so replaced that too.

Drained 40 gallons of questionable fuel and replaced.

WOT for 25 miles and no issues.

Thanks to those who replied.