black max very high water pressure

[GKT]

i have a 1980 mercury black max 200hp. when i got the motor the thermostats and poppet valve was removed. i put all this back in brand new. and i got a water temperature and pressure gauge installed too. i also rebuilt the water pump. when i start it up im reading 15 pounds of pressure at idle... and the motor never overheates or anything. when i rev it up it goes up to like 30 pounds at 2000rpm. i also notice the two or 3 little holes on the lower unit dont have water coming out of them. it just dribbles out every once in a while. i have something blocked up in the water passages i suppose but how do i clear it out?

 

[GKT]

Re: black max very high water pressure

also there is a small fitting on the starboard side of the engine below the throttle arm connected to the thermostat lines and when the line is unhooked from the fitting i have no water coming out of there at all...and only a tiny bit when i rev up to 2000rpm.

 

[Faztbullet]

Re: black max very high water pressure

Has this motor ran before??? If stock adapter plate and thermostats and poppet valve was removed it was getting hot!! This may explain some off your problems in other post. The 2.4 chrome bore dont like to get hot and cylinders can go out of round and chrome still look good.

 

[GKT]

Re: black max very high water pressure

yes ive ran it twice on the lake before. preformed flawlessly. i pulled the exhaust plate and i noticed pieces of impeller lodged in 2 of the passages before i put new impeller in. i think it ran hot before i bought it. but its never run hot on me

 

[j_martin]

Re: black max very high water pressure

yes ive ran it twice on the lake before. preformed flawlessly. i pulled the exhaust plate and i noticed pieces of impeller lodged in 2 of the passages before i put new impeller in. i think it ran hot before i bought it. but its never run hot on me

There's your clue. More pieces of impeller are likely caught in the exit ports in the base plate.