200hp black max

[Karl_Childers]

I just got a 1988 200hp black max. Water is comming out the tell tale just fine while on the hose, but the heads are a little warm. When I ran it this past weekend It got really hot and stopped comming out the tell tale so good. I put her on the trailer and took her home. When she had cooled down she was back to "normal" on the hose. I have 120 compression on all cylinders, and haven't pulled the gearcase yet to inspect the pump. I pulled the t-stat covers only to find someone had removed the thermostats. Will removing the t-stat cause it to run hot? Also, I have heard that some Mercs have a rubber grommet in the water tube between the block and midsection that is prone to failure and loss of water flow. Is this the case on the black max. Thanks for your time!!!

Rob

 

[CharlieB]

Re: 200hp black max

Big difference being on the water vs on the hose.

City water pressure will mask a failing water pump and falsely give you the impression that the cooling system is fine.

Drop the lower unit and service the water pump.

Reinstall NEW thermostats.

retest cooling at the dock.