loud alarm at high trim

[tholsworth]

I have a 2009 Mercury 115 two stroke, a loud alarm sounds continuously when I trim it way up for maximum speed (5,900 rpm) the alarm quits when I trim it down a bit. also, the in dash water gauge was not working. is this normal? thanks, Tim

 

[Dukedog]

Jack plate? Motor is to high ta use that much trim. That's an over heat alarm. Something is wrong with your "set up" (offset, motor height, prop) if ya gotta have that much trim angle ta get your speed........jmo

 

[Texasmark]

As I recall Walleyehed was the one who said that for high engine mounting/trim positions you had to plug the upper couple of engine water inlet holes (2 per side) on the lower unit to allow proper water pressure to cool the engine. If any of the inlet holes come out of the water, the water pressure from those in the water will be forced out of these holes rather than into the water pump and on into the engine.

Curious as to who he is? His name and work are all over this site. Not a Johnny-come-lately by any means.

HTH,
Mark

 

[Texasmark]

As I recall Walleyehed was the one who said that for high engine mounting/trim positions you had to plug the upper couple of engine water inlet holes (2 per side) on the lower unit to allow proper water pressure to cool the engine. If any of the inlet holes come out of the water, the water pressure from those in the water will be forced out of these holes rather than into the water pump and on into the engine.

HTH,
Mark

 

[Dukedog]

We've been doing that for years. Next best thing to lpw for runnin' it higher than normal on a semi-hot rod........Not necessary for boat ridin' week-enders.....

 

[enginepower]

Yep, you are probably losing water pressure due to ingesting air and since you don't have a working gauge, you can't verify it. You can try plugging about the first 2 or 3 top holes on each side as texasmark suggested with something like a small allen hex screw or trim it down where it doesn't beep. If your motor is set too high on a jack plate, can be a problem as well.

 

[tholsworth]

this makes perfect sense, thanks to everyone for sharing the information.

Tim