Overheating at idle
 

Hey guys, need some input. Have a 89 Scarab, 350 mag. Engine is heating up at idle. Put a new Impeller, new t-stat, new stopper in the water housing tree. Boat runs between 160-190F at crusing speeds and WOT...At idle, the engine is still trying to heat up. with the boat in neutral and RPM's up to 2500, the engine will cool down to 160F. I am thinking I need to replace the engine water pump. Any Input?

You might need to clean out your exhaust manifolds & risers. They get scale built up that decreases water flow, & backflush your oil & p/s coolers too. There could be pieces of old impellers partially clogging them.

I can look at those, but i put new manifolds on 3 years ago.

Manifolds look good. Think I am going to pull down lower unit again. I am thinking I have a defected impeller