High pitched alarm when I go over 3000 rpm

[Blaw]

I have a Mercury OPTIMAX 115hp outboard and last weekend I ran into some shallow water and kicked up some mud from the bottom. No when I get the motor over 3000 rpm a high pitched alarm sounds and the engine automatically reduces rpms and my speedometer no longer works. I called a local shop and they said that it was probabaly a high temp alarm and my water pumb might be out. They also said the speedometer works off a small hole on the lower unit it it was probabaly clogged. It is possible I got mud in the lower unit that could be causing both and if so can I clean it without taking it apart? I don't want to use a pressure washing and break something else. Thanks for any help that you can give me.

 

[aussieflash]

Re: High pitched alarm when I go over 3000 rpm

Firstly is your motor still squirting water at rear.You may have a clogged water intake and lines.Yes that alarm is your overheat and it goes into protection mode by reducing RPM.
Start by taking off visible water hoses and inspect for mud etc.You may be able to flush with medium pressure,though I'd be taking it apart and clean well.

 

[pbgeneral]

Re: High pitched alarm when I go over 3000 rpm

The local shop gave you correct info. You may have sucked some mud and sand up into the water pump and damaged the pump or clogged some water passages. Even though you may still have water comming out the tell tail, it might not be sufficient water flow or pressure to cool the cylinders. I would pull the lower unit and inspect and clean all passages and replace the impeller.

 

[Blaw]

Re: High pitched alarm when I go over 3000 rpm

I don't know if it is out the rear, I know it is out the "pisser" hole on the side. Unfortunately I don't have the tools or know how to remove the bottom unit to clean it. I might have to take it to the shop and have them just go ahead and change the water pump. Everyone that I have talked to tells me to replace the water pump about every three years and it is a 2007.

 

[pbgeneral]

Re: High pitched alarm when I go over 3000 rpm

I don't know if it is out the rear, I know it is out the "pisser" hole on the side. Unfortunately I don't have the tools or know how to remove the bottom unit to clean it. I might have to take it to the shop and have them just go ahead and change the water pump. Everyone that I have talked to tells me to replace the water pump about every three years and it is a 2007.

I am not 100% percent sure if your motor has a high volume or a high pressure pump, but the high pressure pumps (impeller) should be changed yearly. and every 2 years on the high volume pumps. If you have not had it changed, and it is a 2007, then yes, it needs to be changed. No special tools required to drop the lower unit, just some time and wrenches. You could do this yourself and save $$$. Buy a manual for your motor and it has all the steps in there to guild you along, plus the great folk here help out a ton.

 

[Blaw]

Re: High pitched alarm when I go over 3000 rpm

Thanks for all the replies. Just got the boat back yesterday and WOW. The therms were completed clogged with sand and the impeller blades were bent. $464 for this repair and $2,000 in 2 months I must get the manual and learn how to fix these things myself.

 

[pbgeneral]

Re: High pitched alarm when I go over 3000 rpm

Yeah it can get exspensive, get you a good manuel and you will learn a lot about your motor, and you may surprise yourself and make minor repairs yourself. That is a great sense of accomplishment. Glad its fixed, and safe boating.