Black Max cooling system question

[ksmarek]

I just recently bought a used boat with an 87 Black Max 175 on the back. when I first took the boat out I noticed it would spit water briefly out of the pisser then stop completly. I would get a steady stream though. The person before me took the thermostats out of it, which in my opinion isnt good. I replaced the water pump and both thermostats today. My water pressure gauge is showing alot more pressure than before but the pisser isnt spitting a steady stream, even at higher rpms. Is the system cooling properly if the water pressure guage says so? I am running the engine on muffs mind you. Haven't put it in the water yet. Just wondering what everyone thought might be my problem? Water pressure is way better than before but its spitting less water? No obstructions in lines either. Any help is greatly appreciated Thanks

 

[j_martin]

Re: Black Max cooling system question

All the water coming out the telltale has gone through the thermostats. If the stats are missing, it should be steady all the time. If it isn't, there almost has to be exhaust getting into the water jacket, or a lot of air being sucked in by the water pump.

Under normal operating, you might or might not get a steady stream on the cuffs. If the supply water is cold, you might not generate enough heat even at high RPMS to open up the thermostats.

If you put it into a lake and put a little pressure on it, like high idle in forward, you will probably see a pretty steady stream.

What I use the telltale for is this. When I first start up the engine, I idle till it spits some, telling me the engine is warm. Then I can blast off without cold seizing my engine.

hope it helps
John

 

[ksmarek]

Re: Black Max cooling system question

Ok thanks john. If I put it in the lake and still don't get a steady stream can I still run the engine without any problems? or should I take the lower unit off and look at the water pump again? Also what and where is the water jacket? Thanks again for your help john. Its much appreciated.

 

[j_martin]

Re: Black Max cooling system question

Ok thanks john. If I put it in the lake and still don't get a steady stream can I still run the engine without any problems? or should I take the lower unit off and look at the water pump again? Also what and where is the water jacket? Thanks again for your help john. Its much appreciated.

The cylinders and combustion chambers are completely surrounded by water, and the combination of ports and spaces in various castings to accomplish that is called the water jacket.

The telltale problem could be a simple as a spider nest in the tube.

If it's actually overheating, it should sound the alarm in the control set and also be obvious by smell, etc. If you can hold your hand on the engine (head for instance) for a coupla seconds, it's not overheated.

hope it helps
John

 

[ksmarek]

Re: Black Max cooling system question

I CAN hold my hand on the block while the motor is running. Its not that hot. could it possibly something I did wrong during assembly of the water pump? almost positive I did it properly but you never know. Also, are the water pressure gauges accurate? The alarm has never sounded, but I am always leary of them going off in the first place. Thanks again for you help John

 

[j_martin]

Re: Black Max cooling system question

Spider/wasp nest.

 

[ksmarek]

Re: Black Max cooling system question

Ok so I took the boat out to the lake today and it ran perfect. Water was spitting out the pisser as it should even at WOT. Thanks for all of your help guys.