Constant alarm on 50hp Mariner with new impellar????/

bitterroot

Cadet
Joined
Mar 27, 2011
Messages
6
My motor earlier this year had a constant alarm for over heating because of a bad impellar and I came on here and you guys were great help so here I am again.

Its a 1992 50hp mariner, like I mentioned I changed the impellar on it and it took care of that alarm problem but now it has a new alarm problem. The alarm has been acting up for the last two weekends and there is nothing consistant about it. Sometimes it will come on at the launch when you are firing it up cold and stay on and other times it will come on after running for 15 minutes full throtle accros the lake. There has even been some instances where it will come on for a minute or two and then shut right off. The other thing that is weird to me about the alarm is that sometimes it is a real loud constant beeeeeeep and other times it is a real faint constant beeep that you won't here unless you at an idle.

The other thing that I am wondering about and this doesn't not have anything to do with the alarm is I am originally from Wisconsin and now live in Montana and the difference in elevation from there to here on some lakes is more than 4000ft, should I be changing the jets on the carb or should I be looking at a new prop??

Thanks in advance for any help. Jake
 

bitterroot

Cadet
Joined
Mar 27, 2011
Messages
6
Re: Constant alarm on 50hp Mariner with new impellar????/

What does the blue tan wire do on the motor? I disconnected it and the alarm shuts off.
 

Tex60

Seaman
Joined
May 31, 2010
Messages
66
Re: Constant alarm on 50hp Mariner with new impellar????/

Ok I'm a rookie around here but since I've been working on my older 50hp Mariner alot lately and have gone through 2 impeller failures I can tell ya that if you run your engine before or after it has water....basically running the engine with a dry impeller you can make it prematurely fail. You didn't mention in your post above if you had a good stream from the "pee" hole to indicate that you had good water flow. If you don't or your getting some steam with the stream then you are running hot and the alarm is doing its job. The reason I say this is the last time I changed my impeller it didn't last as long as the previous one, I learned another trick that can help with this an old timer told me to take finger covered with 30wt oil and wipe the inside of the houseing that the impeller goes in with a thin coat so that the first time you crank it with the new impeller in a dry housing before it starts pumping it wont damage it. Maybe someone could answer with how hot the temp alarm is supposed to activate at and you could use a heat gun to measure the temp at the spark plug where the temp sensor is to see if it is reading correctly.
 

bitterroot

Cadet
Joined
Mar 27, 2011
Messages
6
Re: Constant alarm on 50hp Mariner with new impellar????/

Tex my pee hole is putting out a good stream and is not warm at all even after a several minutes of running at high rpm. The thing that seems odd to me is that the alarm is always on now even without the motor actually running just the key in the on position. I replaced the impellar 2 months ago and have only ran 5-7 hours since. Is there a sensor that could have failed?
 

aussieflash

Lieutenant Junior Grade
Joined
Feb 5, 2011
Messages
1,004
Re: Constant alarm on 50hp Mariner with new impellar????/

Well it isn't overheating when off,so definitely a sensor/ wiring problem.Had the same problem with my oil sensor.
 
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