Pro XS water pressure issues

[smbass77]

hi All, since my mechanic can't get me in for another 4 weeks, was hoping this may be a simple issue/fix. Please keep in mind I'm not the most mechanically savy angler :)

Motor has about 80 hours on it, and I tend to run in shallow water and through grass. One day it took a while for water to start peeing and it was at maybe .5psi at idle, and the alarm went off. If I give it a little throttle (to 800rpm), I get about 2psi and as long as I keep a little throttle on it in neutral, the alarm doesn't sound. When running, I'm typically at 20psi or so, but since this issue developed I can be anywhere from 10psi to 20psi at WOT. One time, after running through some grass, it did drop to 7psi.

I have back flushed the motor a few times which seems to help but my psi is still very inconsistent. Some times it is normal, other times it will be very low.....all in the same day.

It almost seems like I have debris somewhere in my water line that blocks/unblocks throughout the day......but I could be wrong.

any ideas on what I can check to maybe rectify this issue for the next 4 weeks until my mechanic can look at it? I'm getting a little worried to keep using the boat in fear of messing up my motor.

This weekend I'm going to try and clean the compressor screen.....could that be my issue?

thanks!

[leonreno]

Compressor screen would not cause low pressure. I would replace water pump as the first step. That is the source of pressure and the only way you know it's functioning properly.

[Tidewater Bass]

I also experienced inconsistent water pressure on a 250 PROXS. The water pump didn't have maybe 10 hours on it so I was confident that wasn't my issue. I pulled both thermostats an found debris preventing them (left bank was worse) from fully closing. You need to clean you strainer for the air compressor. No water or only a little water coming out of the pee indicator shows what flow is cooling your compressor. Should you allow the compressor to overheat (no or limited coolant flow) it will fail and cost you $$$. Look at the information on the Merc forum it shows you how to clean it. It only took about 45 mins and I hadn't did it before. I could easily complete that task in 20 mins or less now that I have done it once.

[smbass77]

Thanks! I'll check that as well. when you were having your issue, did it take a while (20-50 seconds) for water to start peeing every time the motor was cranked?

[Tidewater Bass]

I never timed it but that sounds about right. Remember the pump has to fill all of the cooling passages before you'll see anything.

[SilverFox579]

I never timed it but that sounds about right. Remember the pump has to fill all of the cooling passages before you'll see anything.

^^^^

[Jetboy]

Not to hyjack your post...Just wondering.. there is no shop that can look at your almost new (80hrs) merc for 4 weeks?
That I thought that was One of the best points about merc everyone works on them? It's under warenty isn't it?