High Water Pressure on gauge

[NPHE]

Just bought a 2016 Sabre with a 150 Merc 4-stroke. Gauge was showing over 30# of pressure (on 0-30lb gauge) at WOT. Replaced the gauge with a new “Marpac” gauge AND line and the new gauge is reading identical to the old one. The engine has never overheated. Does anyone know what the water pressure should run on this engine. Has anyone ever had HIGH pressure like this?

[schodackbassman]

Mine (original analog) goes all the way around and hits the needle on the back side. But it doesn’t fall all the way back to zero either. Don’t know if there is a way to reset or re-calibrate.

[NPHE]

Mine returns to zero. It appears to work fine until I get it up on plane and trim it up. Then it starts drifting until it goes above 30 lbs.

[Wheelman]

Depending on the engine height, trim angle and speed mine will do that. Curious what your pad to prop measurement is and what speed/rpm you’re running?

[bwp777]

that camera is waaaaay too far from that fish

[NPHE]

Wheelman wrote: Depending on the engine height, trim angle and speed mine will do that. Curious what your pad to prop measurement is and what speed/rpm you’re running?

Adjusted engine height when first got it to get a hole shot that I liked. I think the pad to prop measurement was 3-1/2 inches. Really not positive about that since I made several changes. Speed was around 60-61 with RPM around 5600.

[NPHE]

bwp777 wrote: that camera is waaaaay too far from that fish

I getcha, the fish was almost four lbs. Was trying to get a pic of my “new” boat mostly.

[Midnight Rider]

Minimum pressure at wide open throttle should be about 12PSI. If you are running WOT and trimmed out properly, and still getting 30 psi, I’d say your engine is too low. Raise it on the jack plate until you either gain rpm with no increase in speed, or water pressure drops below 12psi. I’d start out at 3″ PTP and go from there. Were you having hole shot problems before you started messing with the engine height? If so, what was happening. What kind of prop are you running, and what pitch?

[Midnight Rider]

PS: you’ll never have to worry about overheating with 30 psi. Gauge may show little to no pressure at idle. As long as it’s peeing a good stream, it’s fine.

[Wheelman]

NPHE wrote:

Wheelman wrote: Depending on the engine height, trim angle and speed mine will do that. Curious what your pad to prop measurement is and what speed/rpm you’re running?

Adjusted engine height when first got it to get a hole shot that I liked. I think the pad to prop measurement was 3-1/2 inches. Really not positive about that since I made several changes. Speed was around 60-61 with RPM around 5600.

What prop and pitch are you turning? Mine came at 3.25″ and I’ve gone down a 1/4″ and up as much as a 1/2″ though like it best all around where it was at. I’ve tried a few props on my FTD with the 150 4-stroke and a 24″ Trophy with all holes out and no exhaust ring is best all around in my experience. I’ve had it up to 66 before running out of water psi/rpm when light and in good weather.

[louie3252]

I had the same set up on my 15 sabre, it would be in normal range, then just pin itself out to 30 randomly like someone missing a shift in a stick shift. Some times it would stay up there and or bounce. I was suspicious of trash at the pickup side of the pressure gauge line at the engine but never did look that hard into it. Never over heated or had any alarms. Those little 4s engines get it, mine would push about 62 with a 23p tempest.

[NPHE]

I’m running a 24 Tempest now.

[NPHE]

I am running a 24 Tempest. I think I will just raise my engine 1/4 inch on the jackplate and see what it shows. If iI am not happy with that I will continue to experiment with motor height and see what happens. Thanks for all your input guys.

[NPHE]

Update. After raising my engine 1/4 inch and running it there gauge showed same thing. Raised it two more times until I got a high temp alarm. Showed 30 lbs plus when alarm sounded. Lowered to original height it was when I purchased it and said I give up and think I just have to live with it. I am not happy about that but am not sure what else to do. I’m wondering now if it is just a characteristic of a Sabre hull.

[Cajunhunter67]

I had a 2011 Sabre FTD with 175 Merc. At WOT I would see 20-25 psi when trimmed for best performance. Prop was 25 Trophy Plus.
I would post this on the Mercury forum on BBC. http://www.bbcboards.net/forumdisplay.php?f=163
30 psi may not mean good flow. If their is blockage, pressure will be high (depending where the water pressure is measured). With 30 psi, you should not be getting an over temp horn. Seems there may be a flow issue.

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