150 Optimax continuous intermittent beeps

NFA

Petty Officer 2nd Class
Joined
Nov 26, 2003
Messages
158
Hey everyone, got an issue with my Opti. Here's the lowdown...

Mercury Optimax V6, 150, DFI, late 90s model.

Last fall it started to beep as soon as I would turn it on. Had it looked at, mechanic said the #5 injector wasn't firing, loose connections, etc etc. He fixed it apparently. Took it out afterwards, it started beeping immediately. Took it back to the mechanic, hooked it up to his computer, looked for codes, and no luck. He went back in to the injector, tightened it up even more and said he had no beeps when it was at his shop. I put it back in to the water today, fired no problem. Ran it for almost a half hour, ran beautifully. Shut it down for 3-4 hours while I fished, fired it back up and immediately got beeps. No idea what it is. According to the Mercury manual, the continuous intermittent beeping has to do with the throttle sensor, but the mechanic said it looked alright. My other guess is oil pressure. I have had the issue where the onboard reservoir doesn't fill up entirely. So I take the cap off and it fills up immediately. That issue would cause a beeping as well, but it would stop beeping once the onboard reservoir fills up.

Other than that, I have no idea what this is. I'm hoping someone on here has some ideas. I'm not looking to fix the thing myself as I'm not that mechanically inclined and I'd rather not tinker on a motor this size. But I am hoping to at least diagnose the problems and share some ideas with the mechanic.

I'm trying to upload a video, I'll add it when I can.

Thanks!
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Just for giggles, test spark again on each cyl. Many of these the alarm 'compares spark signal from one of the cyls to the signal from the oil pump rotation sensor. A misfire on the particular cyl will often cause an beeping oil alarm.
 

NFA

Petty Officer 2nd Class
Joined
Nov 26, 2003
Messages
158
Thanks for the responses guys. Oil, oil flow, oil injection, etc has all been ruled out. We are currently in the middle of checking the TPS's and will report back later.

I will try the spark again if the TPS swap outs don't do it.

The Opti manual says TPS with continuous intermittent beeping as well, so I'm hoping this is it so I can get back to boating and fishing!
 

NFA

Petty Officer 2nd Class
Joined
Nov 26, 2003
Messages
158
UPDATE: Found one of the TPSs to be loose and vibrating while engine was running. Upon closer inspection we noticed one of the bolts to be missing. Three bolts hold the TPS on and there were only two holding it. So the TPS was shifting and moving while the engine was running. This caused the beeping.

We mounted one more bolt to the TPS, nice and tight, and no more beeps. Easy cheesy.
 
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