89 200 no water in port head

[BQUICK]

OK, thanks.
I'll try plugging the telltale next and see what happens.

I'm surprised that the head gasket is holding with numerous overheats and also running the Barnacle Buster acid thru it. Or, maybe it is leaking on the top cylinder and hot combustion gas getting in. But, I would think it would be getting into cylinder as well but no evidence of that....yet.

Damn motor runs good or I would give up. Hit 42 mph yesterday 5500 rpm on both motors before overheat. (1988 31 Stamas)

[BQUICK]

Overheat cured!!!
Ran crossover between tstat housings like many Mercs and OMCs have.
Yamaha missed the boat on this....a lot better way to cross over water rather than relying on lower block that accumulates deposits and can't be accessed.

Ran 15 min at 4000 and never got above 1/4 on gauge. Stopped a heat gunned heat that used to run hot and only 117 deg( was 215 last time out)....maybe need to put the stats back in!

Seems like this wouldn't hurt any V6 2 stroke Yamaha for better cooling.....


Note my Visegrip holding head on....haha

[BQUICK]

Better pic of Visegrip

[BQUICK]

Yes, genuine Yamaha....bolts to block.

[BQUICK]

Highly recommend the crossover hose. Running almost too cool 1/8 on gauge. Put stats back in. Still cool. Heat sensor back in as well. Just ran 20 min at 4200 with no heat up.
I bet a lot of Florida motors are not crossing much water over this makes it happen!
Virtually impossible to get that seriously caked salt deposit out of the lower passage. Even with cleaned out heads I was overheating.

Top cylinder on port side is getting a touch of water so all is not perfect but par for the course with 5 major over heat events. (pinned the water temp gauge with cylinder head sensor pulled out)