over heat alarm 150 hp Yamaha 4 stroke 2006

[sullmate]

My 24 ft. Regulator has 2 engines. Both 2006, 870 hours. All salt water use. The port engine overheat alarm goes off at 5-5600 rpm. I have replaced the impeller, thermostat and overheat sensor. No change. Is there a water pressure sensor on this engine? THE ENGINE IS NOT OVERHEATING. Runs at normal temperature. Is there a code that the computer can spit out? I don't have the tool to read codes. Could ventilation cause a low water pressure condition? If so, it is new this year. Thoughts please. Thanks

 

[QBhoy]

Hi. Is it defo an overheat alarm and not an rpm limiter alarm ?

 

[boscoe99]

There is no RPM limiter alarm on any Yamaha outboard motor. OP's motor alarms for either over temperature or low oil pressure. A steady horn.

A beep beep beep tone will indicate for the presence of water in the water separating fuel filter but only when the motor is in neutral.

 

[sullmate]

its a steady beeeeeeeep. Engine cuts back to a slower speed. Turn off engine restart no beep. No beep at all until boat is driven a while at higher rpm. Engine does not run hot.
is there a water pressure sensor. ??

 

[sullmate]

Max rpm for this engine is about 5200 rpm. not higher

 

[sullmate]

Update. The Yamaha mechanic says it is definately another sensor besides the overheat sensor that I replaced. Not sure what sensor or where it is. I will continue to update when the mechanic does the work.

 

[bigblocksarefun]

Max rpm for this engine is about 5200 rpm. not higher

Max rpm for an F150 is definitely not 5200:

 

[99yam40]

Update. The Yamaha mechanic says it is definately another sensor besides the overheat sensor that I replaced. Not sure what sensor or where it is. I will continue to update when the mechanic does the work.

seems I remember reading about a temp sensor and another switch or something that monitors temps.
Yes let us know what you come up with

 

[sullmate]

The computer spit out a code for another sensor that has to be replaced. The mechanic said the stator and rectifier must also be replaced due to excessive corrosion. The engine (2006) has always been used in salt water in the northeast. I have not received the total bill estimate. Bummer!

 

[sullmate]

Update. total estimate w/ tax $K. Includes New Stator / pulser coil base assembly New oil pump for the port engine. New balancer assemblies for both engines. O rings, crankcase seals and new anodes. Parts,( All Yamaha) total $2418. Labor, 11 hours $1430. ($130 per hour) Work is done off season, in Connecticut. The engine was run in a test tank. Can't run in the sound until May 2023. Ouch !

 

[saltchuckmatt]

Update. total estimate w/ tax $K. Includes New Stator / pulser coil base assembly New oil pump for the port engine. New balancer assemblies for both engines. O rings, crankcase seals and new anodes. Parts,( All Yamaha) total $2418. Labor, 11 hours $1430. ($130 per hour) Work is done off season, in Connecticut. The engine was run in a test tank. Can't run in the sound until May 2023. Ouch !

Anyone say why the overheat alarm was going off?

 

[sullmate]

replaced the water pump in both engines. No alarm. Engine suffered a salt water leak in the powerhead the sprayed the engine with salt water. This caused many electrical parts to corrode. Engine was tested in a test tank. No alarm. Can't water test till spring. COLD here in Ct.