High water pressure 225 promax

**Dave Strong** · 05-27-2020, 08:22 PM

Originally Posted by Bunger

lucky hahah.

ive flushed everything replaced every gasket other than the heads replaced t stats and poppet. At this point only other thing I can think to try is another water pump. I’m at my wits end

Been that wsy since spring of 97.

Dave

**Dave Strong** · 05-27-2020, 08:24 PM

Originally Posted by Bunger

lucky hahah.

ive flushed everything replaced every gasket other than the heads replaced t stats and poppet. At this point only other thing I can think to try is another water pump. I’m at my wits end

Have you got the heads off? Did someone install diverters between the cyls?

Dave

**Bunger** · 05-27-2020, 08:25 PM

Originally Posted by Dave Strong

Have you got the heads off? Did someone install diverters between the cyls?

Dave

heads are the only thing I haven’t pulled. No reason, I haven’t found a spec of sand or corrosion or anything else to make me think there is a clog. Every thing has been thoroughly flushed and everything flows freely

**Bunger** · 05-27-2020, 08:26 PM

Originally Posted by Dave Strong

Have you got the heads off? Did someone install diverters between the cyls?

Dave

the motor has been apart with the previous owner it lost a cylinder so I’m assuming they installed them. Just prices of 3/8 water line wedge in the water jacket correct?

**Dave Strong** · 05-27-2020, 08:37 PM

Originally Posted by Bunger

the motor has been apart with the previous owner it lost a cylinder so I’m assuming they installed them. Just prices of 3/8 water line wedge in the water jacket correct?

Get rid of them only needed with open poppet and washers in place of stats.

Dave

**Bunger** · 05-27-2020, 08:39 PM

Originally Posted by Dave Strong

Get rid of them only needed with open poppet and washers in place of stats.

Dave

gotcha. But I don’t think that’s causing my issue. Water pressure was same as yours before I changed the water pump

**Dave Strong** · 05-27-2020, 08:54 PM

Originally Posted by Bunger

gotcha. But I don’t think that’s causing my issue. Water pressure was same as yours before I changed the water pump

You just put a good impeller in now you got high water press. Get rid of those diverters. Stock cooling system should work like a stock motor, modify stuff and chit gets weird.

Dave

Dave

**Bunger** · 05-27-2020, 09:01 PM

Originally Posted by Dave Strong

You just put a good impeller in now you got high water press. Get rid of those diverters. Stock cooling system should work like a stock motor, modify stuff and chit gets weird.

Dave

Dave

indont know that the diverters are in there I just remember my old 260 having them. I’ve put new water pumps in it before without this issue. Trying to figure out if there’s anything I could have done putting the pump in to cause this

**Dave Strong** · 05-27-2020, 09:07 PM

Originally Posted by Bunger

indont know that the diverters are in there I just remember my old 260 having them. I’ve put new water pumps in it before without this issue. Trying to figure out if there’s anything I could have done putting the pump in to cause this

It's the only thing you hVe not sddressed, yank them heads.

Dave

**tux974** · 05-28-2020, 05:08 AM

Originally Posted by seansbaja1982

Tux u mean replace to replace the impeller? I have the same thing going on as Bunger...

Not necessarily saying to replace it but at the very least I would take pump apart and double check everything especially if all else checks out.

Originally Posted by Dave Strong

If someone installed diverters as a 260 would that cause this?

Dave

Dave, do not think so because the PM's came with them. They there to build heat.
Funny is I had a discussion with Tommy tljkw awhile back to see if he knew why the production 200 motors never came with them but we could not come up with an answer. I put them in especially up here in the colder waters and most definitely with a 1pc plate application on all steel sleeve motors.

Bunger, I would agree with Dave to pull heads a small rock or debri in even the rectangular circulating slots or elsewhere could make things act up.
Is you gauge steady or bouncing pressure?

Below is a picture how they came from Mercury.

**tlwjkw** · 05-28-2020, 05:26 AM

Tux, are ya sure tha pro max came with those???.. i only remember tha nic/chrome hi po motors havin' 'em?.. but ya right.. will not have anything ta do with pressure.. hope he finds something soon 'fore he goes off ona an unscheduled trip!!!..ha.

**tux974** · 05-28-2020, 05:33 AM

Originally Posted by tlwjkw

Tux, are ya sure tha pro max came with those???.. i only remember tha nic/chrome hi po motors havin' 'em?.. but ya right.. will not have anything ta do with pressure.. hope he finds something soon 'fore he goes off ona an unscheduled trip!!!..ha.

LOL, LOL.
Tommy yes. That is why I put that picture up in case he wanted to check location on his.. That motors is exactly how it came from Mercury with maybe 200hrs just opened it up to refresh with new pistons, bearings etc.
Yes, nothing to do with pressure.

**Merc 2.5** · 05-28-2020, 05:39 AM

I had a 2.4 200 that I had really high pressure and I couldn't get it down to save my life , motor wasnt runnin hot or cold , so I just ran it. Not sayin that's what u should do tho

**Bunger** · 05-28-2020, 06:02 AM

Gotcha. I have a set of .75 head gaskets to replace them
with. No idea what thickness is on there now. Are those ok to run? Maybe but the compression sup a few psi is all right? I typically run a mix of 100LL and 91 pump anyways

did you guys see the pics of my number 2 plug and the left bank being washed and cleaner than the right bank? Any ideas

**Merc 2.5** · 05-28-2020, 07:00 AM

Originally Posted by Bunger

Is the poppet valve even suppose to open at idle?

Not sure if sumone answered this but ur stats will control idle temp and poppet takes over to control temp when running.

I dont no enuff bout efi to comment on plug. Ecu driver fires 2 injectors I believe , so that would make me think there would b 2 dark ones if it was ecu thing?