2011 Yamaha 250HP OX66 SX250 overheating

[Robert Louis]

My SX250 is overheating when over 1500 rpm. I've watched it signal over heat with the flashing temp blinking on the Tach, but it simultaneously sounds the alarm at the same time. Is that typical? both going off at the same time?

Can error codes be read of an OX66 SX250? Before embarking on replacing water pump, thermostats, pressure control valve..., it would be nice to read any error codes if possible.

Boat used in salt water, always flushed with fresh water for 30 minutes after every use.

Also interesting, motor cowling doesn't ever feel overly hot when alarm sounds. And, seems to take only 15 minutes of drifting (each time) to cool down so alarm and temp indicator goes off. The event consistency makes me want to consider electrical problem?

Appreciate any feedback. Thanks in adavance.

[Robert Louis]

Mis-type

Mis-type on year, 2001 OX-66 SX250.

[DennisG01]

Unless I'm mistaken, reading the codes is only going to tell you what you already know. Codes only tell you what senso is complaining, not the reason for the complaining. That's where good 'old fashioned detective/diagnosis procedures come in or the reason you pay a technician to put food on the table for his family.

It could be anything from an impeller to t-stats to a faulty sensor to clogged water passageways. Pulling the lower unit and inspecting the impeller is free - might as well start there.

[Poorsche]

Had same problem with my 200HP OX66's -- culprit was salt build up in the water passage in the cylinder heads.

Had to remove the heads and clean with ON-OFF ( muriatic acid). Had issues with some of the bolts and had to use inserts for some plugs and some blts. Also had to mill heads while they were off

I tried everything to resolve problem before I took the heads off -- Good Luck

[Robert Louis]

Thanks for the feedback. Boat is being hauled out next week, so will start the repair 'maintenance' program (pump, stats, pressure valve...). See what works. If there is anything else I should be addressing at this time, please let me know. I think I will be ordering parts from Boats.net, do you have other favorite Yamaha Parts suppliers? Thanks again.