shawn

One of my 1999 HP 500s with carbs sets off the warning buzzers with water at 160 deg, oil at 190 deg and 60 lbs of oil pressure.

I have replaced the impellers, the thermostats, the temp sender and the buzzer sender near the thermostat.

This will happen while cruising at 3,000 RPMs or whenever it feels like it. The other motor set off the buzzer once.

I think its an electrical problem, but don't know where to start looking.

I disconected the really irritating sender wire last time out and the other side buzzed until I hammered it and finally it stopped.


Its my understanding that the buzzers have one wire hot and the senders, four in all, are ganged together and one lead wire goes to the buzzer as the ground setting off the buzzer.

Are there different buzzer senders for the oil temp and pressure and the outdrive fluid level?

Any help with a plan of attack is appreciated.

Thanks in advance

Shawn

US1 Fountain

iTrader: (1)

I assume your drive oil is full?
You are correct, all senders are wired (brown w/blue strip) to a single common buzzer. The senders are all different. Might unhook all warning senders and see if problem continues. If so, the brown/blue wire may be pinched and is grounding out somewhere.

shawn

Yes, the drive fluid is full.
I disconnected the water temp sender and the buzzer stopped.

Would it help to replace this wire, or is something somewhere else in the engine searching for a ground?

These senders are not hooked up in series are they? If I disconnect one, the others will still work, correct?

mopower

Shawn,
Yes, if you disconnect one sender the rest will still work.

If you disconnected the temp wire and it stopped , that means THAT sender is giving you the ground necessary to operate the buzzer and changing ANY wire will not help .

US1 Fountain

iTrader: (1)

Remove the sender wire and see if the sender shows continuity from the terminal to ground while motor is cold. Or at least below 190*F. Should be none.

You can check its operation by removing it and using an ohmmeter. With meter leads to terminal and to the hex body of the sender, you should have no continuity. Now place sender in hot water with a thermometer, still wired as before. When water temps hits 190-200F, you should now show continuity. (alarm would go off at that point) When water cools down to 150-170F, you will have no continuity again.


No, they are not connected in series, that would kinda make the 3 senders after the 1st one useless.