free 1971 stamas boat overheating

[z28se]

i got a free 1971 stamas boat with a 165 mercruser engine



i have rebuilt the carb and have gotten the engine running good. i also installed a new impeller as for the old one was in pieces.

today i took it down to the lake to try it out. before we left the dock i removed the hose coming from the impeller to check for water and it was pumping so i hooked it back up and left the dock after 8 mins of WOT i could feel that the engine was overheating and sure enough it was, wile in the middle of the lake i again checked for water flow and it was working i hooked it back and idled back to the dock.
it is a new impeller and i cant believe it is failling.
by the way there is no thermostat installed so thats not my problem
any help or advice would be nice.

Also when my engine runs i hear the sound like a bad bearing or something right behind the motor where the outdrive is connected. could this be the universal joint or something?

 

[jerryjerry05]

Re: free 1971 stamas boat overheating

If you filled out the profile we'd know where you were from and if you were in salt water or fresh.You need the thermostat in the system.Without it the water just flows thru the easiest way and won't cool the block.The connecting tube might not have matched in the drive and only pumping minimum water.Then the Riser/manifold could be clogged.Allowing small amounts of water but under load not enough to cool.The riser would probably be the problem as the manifold hardly ever went bad(unless you run in salt water).
The noiuse you hear is probably the gimbal bearing.Remove the drive and where the driveshaft goes to the coupler turn the bearing(from the outside).MUST be smooth
ANYTHING other than SMOOTH is bad.

Put the thermo back in and then test the rest. J