Water pressure problem

[Gray Bomber]

I've got a 2007 optimax 200. Got it on the water for the 1st time this year last week. It was cold that day and all day I only ran about 4500 rpm. On the way back to the ramp I decieded to open it up a little. ata about 5100 an alarm went off. I looked at the water pressure and it was only about 5. I set down then took off again water pressure went up to about 15 then down to 10 after I got on plane, I then held the throttle steady at 4500 and the water pressure slowly dropped down to 5 and held. So the next day I went and got a new impeller and put it in. However the impeller I took out looked relly good. Went back to the lake and nothing changed. As long as I run less then 5000 rpm I get no alarms so don't think it's running hot but it wont ever get over 5 psi of pressure. somepeople i've ask said it could be the motor sitting to high but the motor is in the same place its been for the last 2 years and i've always had good enough pressure.

 

[tie1on]

May be an electronics problem.

 

[tie1on]

I ment an electrical problem, not electronic! Like the slingblade pic. emoLaugh

 

[IFish]

Saturday before last Basser#9 and myself took off and I got a little up the river and noticed that my water pressure was on 5 and after my heart attack I look back and it was still peeing good. Realized it was frozen. Later that day it thawd and started working properly. Just thought I'd offer the that.

 

[Guest]

sounds like u may have poppet valve or thermostat trouble. also check the front nose of the gearcase some merc gearcase's have water intakes on the front of the case as well as on the side make sure that they are clear. thats were u get most of your water at high speeds.

 

[wrechin2]

It may be a popet or broken themostat. A thermostat wopuld be low pressure all the time. A poppet can vary. Some people put epoxy in the a few of the holes has the putty fell out? How is is peeing when this happens?? Just a thought.

 

[Gray Bomber]

It always pees but it's not a good strong stream. When I 1st put it in the water it does have a good stream but then slacks off after being run.

 

[wrechin2]

There are ao many possibilities. Most of the time I see issues with too much water pressure and that causes them to overheat. Doesn't move the water quick enough through the block cause of a restriction causing high pressure. But you can see it slowly go down?? What does the alarm sound like? Solid beep or intermitt? I have had oil issues get mistaken for overheat. Just have to ask. May be a simple gauge problem with a oil system issue. Just a thought. Have seen stranger!!!

 

[Gray Bomber]

It's one steady beep

 

[sdfd504]

I talked to one of the great Mercury Techs over on bassboatcentral.com and this is what he said.


"Thermostats, *poppet valve*, and air compressor screen would be my first items to check.

Poppet is the most likely problem. "

 

[Gray Bomber]

Thanks for the help. Think i'm going to have it looked at this week. I'm not brave enough to dig to deep into it myself. But now I have a few ideas as to what it might be.

 

[sdfd504]

The Tech really knows his DFI motors so I would bet it is something that he listed.

 

[wrechin2]

Solid beep is overheat. You would be surprised at how many people don't know that. I am curious how a air compressor screen would cause low water pressure? I am not up to date on the DFI's unless it has a water cooled compressor. I could see a popet staying open causing low pressure. Thermostat would always be low unless the broken part is lodged and then moves, or something is lodged in the inlet tube or under the adapter plate just prior to LARGE water inlet just behind the exhaust. After that it would be a restriction would cause HIGH water pressure. One other thing I just thought of. On the "small" water pumps there is a issue with lower base plate blowing and would suck air when the boat would get on plane. That has the "large" water pump. It is pretty cut and dry. Kit ususally comes with both gaskets and a wear plate. You did change both gaskets when you replaced it right??? Possible gasket issue there pulling air if not.

 

[wrechin2]

I just looked, from what I can tell the compressor is not water cooled(from what I can see) but does have a tempature switch. If a Air inlet screen is stopped up I can see it causing the tempature to increase and setting off the alarm, but still if it is a stopped up screen on the water side it would be HIGH water pressure. You are having low water pressure. Did you check the screen for anyuthing or lost epoxy? Just a thought.</p>

I have seen stranger thing be a problem you would never had dreamed. I had a 2004 hemi truck (when I worked at prebul!LOL) that a customer complaint was dies sometimes when coming to a stop. You should have seen the look on his face when I told him we turned the front rotors and deglazed the pads to correct this!! Then I explained on a Hemi truck has electronic throttle and all trucks have rear abs. On then hemi it has 1 speed sensor on the left front. With electronic throttle we monitor both front and rear wheel speeds. if you are spinning, difference in front and rear speeds, the pcm kills the injectors to lower the rpm to gain traction, the turn them back on. The issue was when coming to a stop at very low speeds the brakes would squeak and this would cause the front speed senor to give a inaccurate reading, then the pcm would kill the injectors to get traction and due to the low rps, it would let the engine stall. After I explained he fully understodd. Maybe this is a case I will understand something new. I like learning new stuff. later</p>

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[wrechin2]

Just remembered another possibility (actually had to do one tonight! LOL!) The gasket between the adapter plates. I built a merc v-6 and installed it today. While running I noticed water running out around the upper engine mount bolt. Had to pull it off and replace it. Just a thought. This on had no issues, was just leaking.

 

[weims]

My gauge froze at the big G last month and scared me to death. When the sun came up it worked fine.

 

[Skeeter]

Sounds like a powerhead gasket to me..... emoGeezer

 

[Gray Bomber]

Wow should have ask Skeeter to start with!!! LOL.... Got a call from the shop and they found a blown powerhead gasket. Hope to get it back in the next few days.

 

[wrechin2]

I put ditchdoc's back on and got it running and it had a blown adapter gasket. Was pouring water out aroung the mount. Had to tear it all the way down. Only thing left on the boat was the trim assy.

There are so many possibilities when it comes to this stuff. They probably seen water running between the powerhead and plate. Glad to hear they found it.