Reply To: 67 33HP Evinrude running very hot

[bob-d]

Don, these are the pictures of the “new” 33 HP head. It’s totally apart. No turning back now! Spent an hour with a high powered flashlight probing, and looking under the head for a bleed hole…..nothing. Also checked the mating surface on the lower unit, no clues there either.
Looked for a blown head gasket as well. No luck on that idea.
In answer to your question, the block was hot in the section under flywheel. Didn’t have a way to measure to see if it was going over the factories recommended 163°. Since I’m on vacation I don’t have all of my tools with me.
Motor turns smoothly. New piston seating very well, no scoring. Shot all water passages with compressed air, on the head and block, they were all clear. Water tube from impeller to head was clear.
Don the question of head compatibility was my first concern when I  was thinking about picking up the 33HP to replace the 28HP powerhead. The only thing I checked was the fact that they used the same part number for the powerhead to lower unit gasket, so I thought I would be good to go?
Although I was dialing in the carb on the motor, and not paying that much attention to the water discharge other than it was flowing ,I’m sure that the hot problem developed after about 3 hours of run time. Even when I ran in the barrel when I started it for the first time after the rebuild I don’t remember it being that hot.
I guess I’ll check the water pickup to water pump circuit next. Will also check the impeller to see if it’s spun on its base. Doubt it, it’s new but don’t remember if it’s a OMC or Chinese knockoff?
Keep the questions coming.
Thanks again,
Bob D