Mercury 150

[Robalo Bill]

This question is for "the boat doc". I could not find a "post" shortcut on Boat Docs' thread. I pulled the boat out this past weekend for a trial run. All went well until I got an irritating constant beep from the helm. I checked the oil, water pump discharge, elec charging all were fine. I did get it to stop once while I fiddled with the trim button on the throttle. This is a 1993 2 stroke 2 litre carb engine. I have a service manual but it does not give reference to this alarm. The alarm always beeps 3 times just before I fire it up then stops when engine is running...not this time....ideas?

[Boat Doc']

If it's a constant horn it's overheating, if it's intermittant the the oil reservoir is low under the cowl or the drive gear is stripped on the crank

[Robalo Bill]

I had changed the water pump last year...lots shooting out of the little hole. Checked the oil...3gal and motor reservoir. I changed the fuel/water filter...dirty gas with top third looks milky. Ran the motor out of the water with a flushing unit attached...the alarm went off right away and stayed on at 10,000 rpm with good water and oil flow. Do these sensors go bad?

Thanks Much
Bill

[Boat Doc']

If this is an EFI motor there is a sensor in the engine mounted filter that detects water and will sound the alarm. Otherwise I need more info. Is it a steady horn or intermittent? EFI or carb? If you don't know give me a serial number.

[Robalo Bill]

Thanks for your response...the alarm goes beep,beep,beep...seems like 300X a minute...no break. My sn is OG005704...carb model. I've included pic of what I got out of the fuel filter.
http://www.ifish.net/gallery/data/500/medium/3750FuelFilterFluid.jpg
This is what the top 2 carbs look like, throttle shutter is discolored.....heat or contaminants?

http://www.ifish.net/gallery/data/505/3750CarbPostRebuild.jpg


This a shot of the Starboard side of the engine.

http://www.ifish.net/gallery/data/505/3750StarboardThermostat1.jpg

Thanks Much
Bill

[Boat Doc']

The motor is sensing an oil injection problem. Verify the reservoir on the engine is completely full. If it is remove the oil pump and pull out the drive gear. Shine a flashlite into the hole and make sure the plastic gear isn't stripped. If both those items are ok then you probably have a senser issue or no spark on #4 cylinder.

[Robalo Bill]

BoatDoc....I pulled the oil pump off and there appears to be no damage to the teeth on the shaft or the driver gear inside. I pulled both sensors and have ordered the parts from th Tigard store. I will also change all the plugs.
http://www.ifish.net/gallery/data/505/3750150Sensors.jpg
Thanks much
Bill

[Robalo Bill]

Boat Doc....did all the above .....alarm still sounding off...any suggetions

Bill