Water pressure TOO high?

[mcgreavster]

I’m having a weird issue on my 1988 XP 150. I installed a water pressure gauge last year and would get around 2-6 psi idle and just over 20 at WOT. This spring I changed my impeller (old one was still in great shape) and now I’m getting closer to 10+ psi idle and 25-28 psi at WOT. At first I was happy with extra PSI until I looked back at the tell tale during my supposed 28psi at full RPM and the tell tall really didn’t look that strong at all. The tell tale looked really strong during idle and even into the 4K RPM range but at 5k+ she looked a little weak so I backed off the throttle for the day and tried to keep in under 4K rpm.

When I got back to the ramp I noticed a little water draining from the inside the cowling, my Tee connector for the water pressure gauge was all wet so I figured I just had a to re tighten my hoses and zip ties and I would be good. However when running it on muffs I noticed water was leaking from the exhaust cover on the back of the motor. I tightened a few bolts and the problem seemed to go away. I’m still getting 10psi at idle on muffs (when I lowered water pressure I was getting closer to 2-4psi).

I plan on heading to the lake in the morning but I have bad feeling when I look back at my tell tale at WOT it’s still going to be weak. Any ideas what would cause this ?

Thanks!

 

[flyingscott]

Is your water pressure gauge teed off of the pee hole line? If it is have you checked for blockages?

 

[Rustywrench]

A few questions first. Has this motor been over heated in the past that you know of? Any wires stuck to the heads, exhaust cover, or jackets of the wires melted? If you look at the parts break down on this motor you will see the parts for the thermostat & pressure relief system. Some plastic & rubber parts that have to be serviced from time to time. Not hard to do, but need to be looked at on this old motor, especially if it's seen an over heat.
The rear exhaust covers had a tendency to loosen up over time. Here you may be running into an exhaust leak entering the cooling water. An exhaust leak could increase you water pressure, but I would not expect the gauge to be steady? More of a pulsing reading. At WOT might smooth out as back pressure is less due to scavageing thru the prop. Just some things to think about.

 

[Scott Danforth]

pressure is the blockage of flow

 

[mcgreavster]

Thanks everyone, had some debri stuck where the telltale hose leaves the motor. Everything is great again.