alarming!!

[jgreen]

I have a 1994 merc 175 EFI, it will run all day long at 36-3800 rpm, trimmed level, my boat has a 6" set back manual jack plate lifted about 3", as soon as I get above 4000 rpm an alarm goes off, its a steady tone not a intermittent beep, when the alarm goes off I pull it back to neutral and shut it down, I sit for just a couple seconds and turn the key back on and the tone is gone. It is pumping a good stream of water and is full of oil. I was told that being the alarm stays off after I shut down for a couple seconds and stays off that I probobly didnt over heat and maybe have just a bad temp. sender. Any body agree or disagree ?

 

[jgreen]

I have a 1994 merc 175 EFI, it will run all day long at 36-3800 rpm, trimmed level, my boat has a 6" set back manual jack plate lifted about 3", as soon as I get above 4000 rpm an alarm goes off, its a steady tone not a intermittent beep, when the alarm goes off I pull it back to neutral and shut it down, I sit for just a couple seconds and turn the key back on and the tone is gone. It is pumping a good stream of water and is full of oil. I was told that being the alarm stays off after I shut down for a couple seconds and stays off that I probobly didnt over heat and maybe have just a bad temp. sender. Any body agree or disagree ?

 

[jkeiper]

Do you have a water pressure gauge?

Jim

 

[Chris]

Can't the oil injection warning, set off the alarm as well?

 

[jkeiper]

Oil warning is not a steady beep.

Jim

 

[jgreen]

I was told by a couple different merc. techs that a steady tone is a temp. alarm they are telling me it could be just an over sensitive temp sending unit, or maybe my water pump isnt pumping quite enough volume to satisfy the computer. I dont have a water pressure guage now but when it comes out of the shop it will. What kind of pressure should it have?

 

[jkeiper]

I would install a water pressure gauge and see if the pressure is dropping off as you increase the speed from 3800 to 4000rpm causing the overheat condition. You might find you are just on the edge at 3800 rpm. I run 15 psi on mine at wot. Do you have the top two inlets plugged? Did you have trouble before you installed the jackplate?

I left you a post in "play to win." Didn't know if you saw it.

Good luck!

Jim

 

[jgreen]

Jim: The top two inlets are not plugged, how do I plug them? and does plugging them effect the temp the motor runs at? Is there any possibility of doing any motor damage with the inlets plugged? I have only had the boat for 3 months, it came with the jack plate and I have not moved it since the day I bought it, assuming that it was performing well at that height for the previous owner. The day I test drove it the weather was terrible very cold and very windy so I didnt run it hard I probobly only ran it to 4500 for a very short burst before I started to freeze my #*# off.

 

[Bigmoss]

A steady alarm like that is a water temp warning. Had the same thing last year with my merc outboard, shot out great water etc. Had the marina look at it and the water pump or water impeller needed changing they did that and all was OK.

BM

 

[jkeiper]

pulse,

My mistake! I thought you added the jackplate and were too high for your water pickups resulting in low pressure and overheating. I agree with Bigmoss in changing the water pump impeller if you don't know when it was changed last. It is easy to do and inexpensive. It could be your temp sensor is bad however, I would still check the other things first.

I tapped the top two holes for 1/8 pipe plugs that use an allen wrench to tighten. Then I filled with JB weld sanded smooth and painted. It turned out great.

Good luck!

Jim

 

[daren34]

if the new water pump does not fix your prob
you probably have sand in the thermostat area
or maybe one is bad
you need water psi gauge
good luck

you should be able to run 4500 all day
what is wide open throttle rpm