06 Yamaha F150 temperature alarm at idle or low speed

[troutboard]

2006 Yamaha F150-TXR
Saltwater use.
3000+ hrs.

Alarm sounds in neutral, idle speed, or when taking off after idling for a bit. Alarm clears with a restart.

Sometimes, but not always, the indicator stream will stop while in neutral, but it picks up normally as RPMs increase.

We have replaced water pump (impeller, gaskets, metal plate and cup).

Just cleaned "poppet" pressure control valve and installed new gasket, grommet, and valve. Spring was cleaned and seems fine and "springy".

Any ideas on what the problem is, or what we should examine next?

[boscoe99]

Are you seeing the over temperature icon flash or an over temperature light illuminate when you hear the alarm?

[Bilge Rat]

If the alarm is a temp. alarm start at the source. Water pump, how old?
How much crud did you see in the water passages when you removed the poppet valve?
Thermostat also needs checking.

High hours on the motor in saltwater may need the water jacket cleaned.

Water pump, poppit valve, and T-stat are wear parts and need replacing on a regular basis.