There could be kinked or blockage in the tube that runs from the transom to the motor and or there could be blockage in the manifolds and risers/elbows. Were they ever replaced?

 

Got 2 of those motors. 161* when all is spot on. Seeing your boating is in fresh water those elbows should last a good long time and those manifolds should last damn near forever. I would be looking at the water pump first, and make sure there are no obstructions in the raw water flow.

 

How did you determine the temperature? My gauge reads on the high side but isn't graduated.

 

My 5.0 liter reads around 170. Could be a gauge issue. Some guys recommend getting a digital thermometer and read from the engine.

 

got call from boat shop today saying they put IR gun on it and it read 175 and they said gauge must be off. Anyone know if there is a difference on brand new engines/boats between gauge and surface temperature? I'm suspicious even at 175. My 30 year old b only runs 2 degrees over even on hot day as they are saying.

 

Do you have Smartctaft? Your engine is definitely Smartcraft capable but some of the smaller bow riders were not equipped with SC for some reason. If it is Smartcraft, it is probably the sending unit since the gauge would read whatever the sender was telling the ECM to register.

 

Mine runs 175 on a hot day and around 170 on a cool day. Not sure what temp thermostat it has in it.

 

I had an '08 non-sear ray bowrider with a 5.0 MPI with 50 freshwater hours that ran 180-190 according to the gauge. I replaced the impeller (Alpha), thermostat, checked all the hoses for kinks/blockage and everything seemed fine. The exhaust manifolds were barely warm after running the boat hard so I just lived with it.

After a year I ended up putting a smartcraft gauge on it and it read 160-161 degrees. There was two different senders on the engine, one for the dash gauge and one for the engine management.

 

my sport 205 runs at 180,no high temp alarm going off

 

Our 205 runs about 185 on the gauge and closer to 170 with an IR gun.

 

IR guns read about 10 deg cooler on the outside temp. If you can get a reading off the front or rear of cylinder head with ir gun it will be closer reading to actual engine temp. If you take it off the intake manifold it will be about 15 deg cooler.

 

There is a temp. difference between the open and closed systems, with closed running cooler like at 161*

 

Just a heads up the gen 2 pump kits had an issue early on they changed the housing and went to a rubber seal to correct and air leak they had.. So if you have the old style housing you may want to upgrade.

 

I'm starting to get some surface cracks in my intake manifold now. This sounds like a good lead. Any idea of when exactly they changed that?

 

mine runs about 175-180 and has done so since new...