1988 Bass Tracker Mariner 45HP Motor Makes Continous Beeping Sound At Full Throttle

[cscott711]

It doesn't make this sound at idle anything below full thottle. In fact, it doesn't make it as soon as it's in full throttle. It takes 1-2 minutes before the continuous beeping sound comes on. Correct me if I'm wrong, but that means "high temp/overheat alert" right?

Water is shooting out of the pee hole just fine. This is the end of my boat motor knowledge and where I hope you guys can give me some pointers. Please let me know what info I should provide and what I should be looking into, thanks!

 

[Texasmark]

Re: 1988 Bass Tracker Mariner 45HP Motor Makes Continous Beeping Sound At Full Thrott

Sounds like your engine isn't getting adequate water flow through it at WOT. Could be the stat not opening fully, or the pop-off valve isn't functioning if your engine has one, or your water pump isn't pumping as it should, usually impeller blades deformed from age, or you have an obstruction in the cooling pickup. Other things could be corroded interior water passages from salt water usage, engine sitting too high on transom to name a couple more.

The stat starts opening at around 143F (does on my 90 anyway). OT sensor shorts out and blows the horn at about 195F and resets at about 175F....numbers from my manual and reading my stat pellet.

So your senario is that at lower speeds, you have adequate cooling to keep the block below 195. At WOT the heat input from the engine exceeds the water flow somewhat and over time the average water temp increases until it hits 195 and blows the horn. Slowing down allows the average temp to fall below 175 and the horn shuts off.

Course timing advanced too far could do it too but you would/should have other indicators of that which you didn't mention.

HTH,
Mark

 

[cscott711]

Re: 1988 Bass Tracker Mariner 45HP Motor Makes Continous Beeping Sound At Full Thrott

That seems to make sense. Thanks for the reply. Sounds like I have a few things to check out.