Water Pressure

[Brian Squyres]

First time posting to the forum and have read a lot of posts but have a question. I have a 2010 Mercury Optimax DFI 150 and the water pressure has dropped in the past couple of months. At WOT and about 5100 RPM, the pressure gauge is at about 11 PSI. From what I remember running it last year, that is a drop in pressure or maybe I am imagining it. The serial number on the engine is 1B765022. I know it is probably time to change the impeller but not sure which part number it needs. Called BPS to see what they would charge and they came in at $325 which seemed a little high to me. Thoughts and advice please. Thanks to all.

 

[C Shiner]

My water pressure rant!



My new 2010 150 Opti always seemed to have low pressure, 2 PSI at 1000 rpm and 10 PSI at WOT. The selling dealer said some motors are higher and some are lower, just the way it is. I never had any alarms. So I checked the gauge line to see if there was a kink or an extra tight tye wrap, I even changed the gauge, no change. Per my local parts dealer starting around 2010 the units have a low pressure high volume pump so my pressures didn

 

[Steve Johansen]

Just be glad that (a) you have a gauge to show your pressure and (b) thatyou have pressure!



As long as you have SOME pressure and you're not overheating you should be OK. You could always change out you impeller, as you said it's time for that anyways, and see what difference it makes.



Let us know!

 

[Brian Squyres]

Chaz,

Was that part number for the entire kit or just the impeller and gaskets?

 

[C Shiner]

Nitro189,



That was a complete kit, pump housing, base plate, gaskets, the one screw, multiple seals, O rings, the shaft key, plastic coolant guide tube, top of housing seal and impeller. Basically if you had nothing you could build a pump from scratch.



I had no idea what I would need so I got it all. If you can handle down time, you could open it up and purchase only what is needed, however, some parts may only be available in the complete kit???



Edit: Let me add, that kit is the high pressure low volume unit.

 

[Brian Squyres]

Thanks Chaz. Looks like I have a project for next weekend.

 

[C Shiner]

Nitro189,



I don

 

[Bob Bourget2]

The Opti 2.5 litre motors are a different animal altogether, with regards to the "water pump". Due to the operating parameters, the necessity of keeping the pumps up-to-snuff are paramount. The WOT specs are 11-14psi. Below that, you'll get an alarm and record in the PCM. You could PROBABLY take the same "worn" impeller out of one of these motors and put it in a conventional carb'ed or EFI motor with no issues. Merc wants to be sure of proper compressor cooling, fuel ratios, and engine longevity.....dictated {in part} from inputs such as engine temp and water pressure. The recommendation....every year for this series of motor. As I've stated in the past...it's cheap insurance.

 

[Brian Squyres]

Thanks for the heads up on the install Chaz and the information Bob. Last thing I want to do is fry the engine. As far as mechanical ability, I can take stuff apart really well and can get all the parts back in most of the time....kidding. I have a buddy who wants to change his impeller out also so we will learn together. Now just gotta get my parts together.