I just happened to look back yesterday and notice that at idle for a few seconds I did not have water pouring out of the flow tube. I started then paying close attention to it all day. I noticed not 100% of the time was water coming out. When the engine was RUNNING at some low to medium and high rpms it was pouring out like a hose but at idle or first starting it didn�t seem to be coming out, only a dribble. Even if I let it idle for a 5 or 15 seconds it was still dribble I had to give it some gas and have it rev up some to get it to start pumping water out. I have the Sportmaster Performance Gear Case in it also on the 1999 Mercury Pro Max 150. I have heard no sirens or beeps saying it was hot or not working and I do not have a head temp gauge. i am speaking of the BEEPS when it is low on oil. I did remove the housing and hand felt the heads and they were both cool. I am not a mechanic and never played one on TV either. It all seems to work great just an observation.

Sportmaster Performance Gear Case


The black little rubber hose on the right side is the hose water comes out.

My memory may be going, but I seem to remember that the ProMax motors had low PSI/high volume water pumps on them. I had a 225 ProMax for years and rarely saw water pressures above 12psi and never had a problem. I would want a water pressure guage on a motor with a Sportmaster on it. Consistant level of water pressure is what I watched. Also, changing the impeller is cheap insurance.

Yeah i changed the impeller not long ago maybe 6 - 8 months.

TTT

At idle on that engine or any 2.5 litres it will dribble or have a weak stream until thermostats open and when you are reving it up at idle or up on plane you are unseating the poppet valve what you are desribing is normal....OPTI

ok great. I just needed someone who knows obviously more than i do say ,"it's ok"

Once again I am glad to a part of TFF.

dont see a lot of pm 150's out there id hang on to that one

I love the motor. That is why I was so concerned that I had no issues. I take extreme good care of it. She is not only nice but all I got and with this economy all I can afford for awhile.

opti gave you excellent info.

my old pro max was the same way!!!!!

would be great idea to instal a temp gauge on the head! and a good psi water gauge.

I agree Steve and see you in April....

what's in april?

don't forget the lake fork open MAY 30th. you need to bring that boat and fish with us!!!