Alarm!

[Bart_Man]

I just had a new (used) powerhead installed on 1 of my 1992 150hp Johnson Ocean Pro outboards and.... the motor seeems to be running great. Prior to blowing up the old one I would get an intermittent alarm after throttling up to approx 4000 rpms. I thought that the alarm would go away when I had the powerhead (and oil pump) replaced. Turns out that I still have the alarm with the new powerhead.

I THINK its an over temp alarm. Its continuous and stops when I back down on the throttle and it only happens when I'm in gear. Since I replaced the powerhead I assume that the problem is with one of the pieces I didn't replace. The water pump is putting out what SEEMS like a sufficient stream and the temp gauge on the dash does not indicate an over temp condition....but I still get the alarm and its always comes on between 3500 and 4000 rpm. Could it be the waterpump? This is making me nuts! I've gone through 2 powerheads this year (different motors) if I blow another one I'll probably have to get a new wife and a new hobby.

 

[reeldutch]

Re: Alarm!

there are 2 things that can set off your alarm.

1 is an overheat condition, you can check the temp with a infrared temp gun.
when it overheats at higher rpm your powerpack should puit the rpms down to 2500 rpm automaticly.
Slow mode.

2 is what i think is causing your problem an vacuum alarm.
meaning you have a vacuum in your fuel system wich causes the cacuum switch to set off your alarm.

check for the propper size fuel hose and check for an open vent at the fuel tank.
run the motor on a plastic 6 gallon tank and see if the alarm go's away.
if it does you have a problem in the boat fuel system and not at the motor.

check for clogged fuel filter and stuff like that.
kinked fuel hose?

good luck.

what happened with the first powerhead did it lean out and blow up?
could be fuel starved without the vacuum alarm working?

reeldutch

 

[MikDee]

Re: Alarm!

Good Advice! ^^^ Plus, I would go over that oil pump, and oil injection system also, to make sure there's no pump aeration (losing prime), or debri clogged vacuum, or discharge lines, or tank, or kinked lines. Good Luck that's got to be a heartbreaker.

 

[Dhadley]

Re: Alarm!

That's a fuel restriction alarm. I can't believe a shop turned it lose with a fuel restriction, regardless of why it was in the shop to start with.

At least you know why the first one gave up.

We always say, the most overlooked part of a rebuild / replacement is finding out what caused the original problem and fixing it. Now you know why we say that.