[oldironman57]

I have looked through alarm logs here a lot but don't find anything that fits my problem. The motor is on a pontoon boat and has had about 6 hours on a new impellor. We were in a large lake with a half hour drive time behind us mostly at WOT when the alarm went off...continous tone. I could not remember whether that was oil or heat. Restarted at idle with a good water stream so I thought possibly oil. Oil tank was 3/4 full with no visible bubbles in the lines. I mixed up a quart of oil into the gas tank with 9 gallons approx left in it. Better safe than sorry. Purged the fuel lines and let it idle for a while to empty out the carb. I was also holding on to the top and sides of the cylinders with no discomfort so I still thought cooling was fine. Odd thing was the alarm stayed on always when the key was on. No off at low rpm then on at WOT type sympton. We stopped and fished for a few hours and re-started the motor and instant alarm again. We started back to shore and the motor would seem to run fine until the last half mile in. We lost the any sort of high RPM. Motor would just die out above 1500 (approx) RPM. It would start and idle fine. Checked the temp on the cylinders again and seemed cool to touch, with no steam out of the tell tale. This is a 96 Mariner 60 (friends boat). I was wondering what is possessing this thing. The continous alarm leades me to a temp sensor. The loss of power scares me. Do these motors have any sort of limp mode? I had good smoke out the exhaust after dumping oil in the tank so I thought I covered that base. Figured I could always change plugs. Thanks for any thoughts. Randy S.

[WillyBWright]

Welcome to iboats Randy. Go Pack!A constant tone is an overheat warning. So there are a few possibilities. Your motor is overheating, doesn't sound like it. Your cooling surfaces are limed-up preventing good heat transfer, usually at high RPMs and goes away at lower RPMs, doesn't sound like it. The sender or wiring could be shorting to ground, a possibility. Or a bad warning module. They sound when they go bad, another possibility. If it's the module, the constant tone will sound any time the key is on if the motor is cold or hot, but it's an electronic device. They can have minds of their own.

[halfpint1]

Ironman--I had the same problem with my 91 40hp Mariner. The constant alarm is supposed to be for overheat,however when mine did this I took it to the local marina and had the mechanic look at it.He checked for overheat and that wasn't the problem so he unplugged all the sensors & the alarm still sounded so we replaced the sensor horn--yahoo cheap fix. Idled great no overheat. However when I took it to the lake the next day still no power when accelerating. Back to dry dock we went where I cleaned & regapped the plugs,removed the bowl from the carb & cleaned it up then I took the oil resovior apart cleaned the float really good and believe it or not when I took it to the lake it ran without a problem. Its still running better than it ever has. Not sure which clean-up fixed it but you could try what I did and see if it works for you. I was probably just lucky but what the heck---I'll settle for that!!!!! Good Luck...

[oldironman57]

Originally posted by WillyBWright: Welcome to iboats Randy. Go Pack!A constant tone is an overheat warning. So there are a few possibilities. Your motor is overheating, doesn't sound like it. Your cooling surfaces are limed-up preventing good heat transfer, usually at high RPMs and goes away at lower RPMs, doesn't sound like it. The sender or wiring could be shorting to ground, a possibility. Or a bad warning module. They sound when they go bad, another possibility. If it's the module, the constant tone will sound any time the key is on if the motor is cold or hot, but it's an electronic device. They can have minds of their own.

[oldironman57]

Thanks all; Compression check done and at 115 on all 3. Start on the wiring check this weekend.Randy