Black Max 150 Water Pressure

[MrMartyr]

Hey All,

I have '93 Black Max 150, with no water pressure guage in dash or elsewhere.

Is it a good idea to monitor this parameter?

Where on the engione is the best place to install pressure guage/guage line?

What would be good pressures to ensure healthy water pump etc, @...
Idle?
WOT?

Love the forun, losts of great help to be had here. Thanks to all that contribute.

 

[section8]

Re: Black Max 150 Water Pressure

google it. its good to have. its a t fitting you splice into the water tubes near the engine block cylinder heads. add a tube that comes with the kit from t fitting to dash and cut hole for guage. hook up wire for light.done. 40 bucks or so. search the forum here for the psi you should have. it was discussed about 3 weeks ago

 

[hl]

Re: Black Max 150 Water Pressure

I just reworked my water plump on my 150. At about 3000 RPM my gage reads around 16 - 17 psi. I have never looked at it wide open.

 

[MrMartyr]

Re: Black Max 150 Water Pressure

google it. its good to have. its a t fitting you splice into the water tubes near the engine block cylinder heads. add a tube that comes with the kit from t fitting to dash and cut hole for guage. hook up wire for light.done. 40 bucks or so. search the forum here for the psi you should have. it was discussed about 3 weeks ago

Section8,
working from memory here...
there are two rubber hoses on the heads. 1 from left head to right at top, other from right head at bottom down to water discharge, has tee for tatletale.

Is the left to right head jumper hose the one you recomend installing the guage line tee into?

Those are the only thing that looked like water hose near the heads.

 

[section8]

Re: Black Max 150 Water Pressure

the spot where the tubes come out of the heads are right after the thermostats. you can easily unbolt and see without new gaskets. i think you can put it in either side. it wont tell you if both stats are opening correctly. but if either one opens it will read pressure in either place you put it. to see if they both open right i run my engine and feel the tubes. they get hot after each head once it opens then i quickly remove the two bolts and look at them while they are hot. but they may open hotter than theyre supposed to if theyre bad. easy to put a temp gauge also. the left head bank has a brass bolt thing sticking out thats the temp sending unit i just dont know if that hooks right to a gauge through a wire or to some module first.

 

[j_martin]

Re: Black Max 150 Water Pressure

The water pump connects to the engine at a pipe threaded hole in the center of the block, just aft the flywheel. It does not connect to the thermostat plumbing in any way.

There may be a plug in that hole, or there may be a line going down to the poppet valve from that hole. Either way, that's where you hook up.

Water pressure is the most useful information for troubleshooting any overheat problem. It is also the earliest warning for cooling system trouble.

For instance, at idle, it should be around 5 lbs. As I was idling through a shallow channel yesterday, mine suddenly went to 10 lbs. I immediately went to neutral, trimmed up as high as possible without losing pressure, and rapped the throttle a couple of times to clear the mud out of the small passages in the engine. Pressure returned to normal, and I proceeded without any trouble. Undetected, that could have been a major overheat on a single cylinder resulting in major damage.

hope it helps
John

 

[MrMartyr]

Re: Black Max 150 Water Pressure

OK, Admiral,

It makes perfect sense to me to read this pressure where it is supplied to tyhe engine. Good so far.

I have viewed several videos on water pump replecement and understand the water tube from the pump, up, to the power head. I do electrical and mechanical repair just not on OBs yet.

But, is this connection point to the block accessible with just the cowel removed? I
If yes can you offer some land marks and "driving directions" to help me find it when i get back out to the boat later today?

 

[j_martin]

Re: Black Max 150 Water Pressure

OK, Admiral,

It makes perfect sense to me to read this pressure where it is supplied to tyhe engine. Good so far.

I have viewed several videos on water pump replecement and understand the water tube from the pump, up, to the power head. I do electrical and mechanical repair just not on OBs yet.

But, is this connection point to the block accessible with just the cowel removed? I
If yes can you offer some land marks and "driving directions" to help me find it when i get back out to the boat later today?

The water pump connects to the engine at a pipe threaded hole in the center of the block, just aft the flywheel. It does not connect to the thermostat plumbing in any way.

There may be a plug in that hole, or there may be a line going down to the poppet valve from that hole. Either way, that's where you hook up.

If you take the cowl off, you'll find a V6 engine block on end. The top has a flywheel on it. If you go just aft (Toward the rear for you landlubbers) the flywheel, looking downward, you'll find said threaded water pressure port.

It should be easily accessible with just the cowl removed.

On mine, there's a barbed adapter to about 1/8 inch hose, and a plastic line goes from there directly to the gauge in the console. Some have a pressure hose that goes to the poppet valve as a pressure signal. On those you can tap into that hose.

hope it helps
john

 

[MrMartyr]

Re: Black Max 150 Water Pressure

I bet I can find that.

Oh, and easy on the whole "landlubber" thing. Ouch!

USN '86 to '90, Shellback and all that.

Thanks for the help Skipper, we boating beginners realy do appreciate it!