90HP Yamaha 2stroke running hot

[Keywest1720]

My 1998 Yamaha ran hot twice yesterday and both times I shut it off immediately. Each time it ran hot after running 5-6 mile @ 4500 rpms. It took about 10 minutes to cool off each time. The motor is running fine and idled for a mile though a no wake zone without running hot. My question is where do I start looking for my problem? water pump or thermostat or is my problem more deeply rooted?

Thanks

[99yam40]

both of those are normal maintenance items,
when were they replace last?
It would be a good idea to have a look at the PRV while you are at it

[robert graham]

Mine is a 1999 Yamaha 90C, similar to yours. Your best bet would be to replace the water pump kit, thermostat and pressure control valve all at the same time, then you'll know what you've got in there. Good Luck!

[Keywest1720]

90 Yamaha

Thanks, both were replaced 3 years ago but not the PRV. The problem was very different and I was scared I may have deeper trouble.

[99yam40]

3 years is not that bad, but I have had a impeller lose vanes in less that a year before when started with out water for just a few seconds.
Could be that water passages are a problem or even corrosion causing a problem. You will not know until you see what everything looks like

[Keywest1720]

Thanks to all for the help. I installed the water pump kit,thermostat, PCV and spring and was not a very tough job. I haven't had a chance to go to the lake to test it but plan to on Friday afternoon or Saturday.

[robert graham]

Good Luck, and let us know if that solved your overheating problems!

[Keywest1720]

Everything seems fine, I ran near 12-13 mile last night @ 5000 rpm and idled with no warning buzzer. My indication stream seems week at idle and doesn't change at higher rpms but the stream is very strong when running the lake
so I am just going with it for now. Thanks again for all the help.

[robert graham]

Great!...sounds like you're good to go

[99yam40]

My indication stream seems week at idle and doesn't change at higher rpms but the stream is very strong when running the lake

Might make sure the housing is OK, could be leaking around shaft area.
High RPM would overcome what was leaking.

Just a thought,as idle should show a good stream also. Maybe blow out tell tail to make sure it is not partially plugged

[Keywest1720]

How can I identify a possible housing leak? Will I have to pull the foot again aor will a leak show uo some other way?

Might make sure the housing is OK, could be leaking around shaft area.
High RPM would overcome what was leaking.

Just a thought,as idle should show a good stream also. Maybe blow out tell tail to make sure it is not partially plugged

[99yam40]

Inspect housing well with it off the motor or just replace