1995 yamaha 150 over heating

[lostinboat]

hi, I have a 1995 yamaha 150hp and it starts overheating at or above 1400 rpm. Have replaced water pump, thermostats, and prv. at idle runs great, no problem with starting. but as soon as it gets at or above 1400rpm ,over heat alarm goes off. Can anyone help? Thanks

 

[rodbolt]

Re: 1995 yamaha 150 over heating

why do you think its overheat ?

 

[lostinboat]

Re: 1995 yamaha 150 over heating

because temp alarm is going off on gauge

 

[rodbolt]

Re: 1995 yamaha 150 over heating

if the temp icon is going off then its a fair indication of an over heat.
use a tempgun or a melt stick to see if its a bad thermo switch or an actual over temp.
just remember the audible is the same tone for all alarms.

 

[lostinboat]

Re: 1995 yamaha 150 over heating

think we found problem, left side water jacket gasket is leaking. thanks for the help.

 

[rodbolt]

Re: 1995 yamaha 150 over heating

I doubt you found it, the water pump and pressure control valve can easily supply enough make up water to overcome about anything up to a dime sized hole.
are you positive its the temp icon lighting up? like I said its the SAME alarm tone and frequency used for ALL alarm conditions.