30hp 2 stroke overheating

[kawie400]

I have a overheating issue.
complete new water pump. Tested overheat sensor. working fine
new thermostat.
pisser is working.
Over heats if running slow for a period of time, overheats when wide open in a short period of time.

Any thoughts?

[kawie400]

Top cylinder running around 140-150 degrees, bottom cylinder running 120-130 while in a bucket.

[Solarman]

Sounds like a corrosion blockage issue preventing cooling water circulation around cylinders. May be able to clear using chemical flush for 1-2 hrs, using large bucket/ other large container, run till solution is pretty warm, then let solution cool, and repeat. Continue doing this chemical flush with the same solution in large bucket, until temps between cylinders equal out.

If this chemical flush (vinegar, salt-away, or other corrosion solution) doesn't clear up the problem, then manually cleaning water passages by opening and scrapping may be your last option?

The temp differences indicate water is not flowing around cylinders cooling them properly.

Good luck. Post back when able. Let us know how its going.