Descaling

[speckman]

I purchased some starbright motor descaling fluid . Do ineed to remove the thermostats from the motor before descaling it? I have a yamaha sx150txrb outboard my engine alarm will go off after it is at idle . I can give it some throttle and the alarm goes away. So im thinking it might need cleaning.

[99yam40]

It would be best to remove the stats so the solution can run thru every place in the power head freely.

but a stuck open PRV can cause that type of problem along with the water pump needing replacement

[boscoe99]

It would be best to remove the stats so the solution can run thru every place in the power head freely.

but a stuck open PRV can cause that type of problem along with the water pump needing replacement

That would be the first thing that I would check.

[speckman]

Ok thank you so much , I will look into this.

[speckman]

Where would I find the Prv in parts breakdown ?

[99yam40]

number 19
Yamaha Outboard 150HP OEM Parts Diagram for Cylinder Crankcase 2 | Boats.net

[boscoe99]

[speckman]

Thank you, you guys are awesome!!

[Keithbaja]

Saltaway or white vinager

[Keithbaja]

Muratic acid can be used if you have experience. Shortly !!