High water pressure 225 promax

**tlwjkw** · 05-28-2020, 07:08 AM

no it shouldn't.. poppet controls tha pressure/discharge which will in turn have some effect on temp........ stats have temp control at all times.......... if they give up tha motor will overheat no mater what tha poppet does........ jmo

**Bunger** · 05-28-2020, 07:11 AM

Originally Posted by Merc 2.5

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?

I was thinking the same thing injection and spark seems to be controlled in 2s and 3s. Plus my brucato acu on it is barely a year old. I’m hoping it’s just a bad plug

**Dave Strong** · 05-28-2020, 09:40 AM

Originally Posted by tux974

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.

Well if thats the case I gave him some bad advise, I don't recall seeing tbem in mine when i cut the heads. But that was along time ago. Remember seeing them in my plated motors, but will take your word for it as you have been inside more of these than all us put together.
Seems strange this began after a new water pump.

Dave

**tlwjkw** · 05-28-2020, 10:11 AM

jus know one thing, they don't show on any parts list or drawings with '94 ta '96.. unlike tha nic motor list and drawings???.. but i'm gettin' more n more dead cells............

**ProComp** · 05-28-2020, 10:27 AM

I'm a little confused because I've owned a ton of promax's and they all run 20lbs of water pressure at speed. If the motor is in the 140 temp range its should be fine.

**Dave Strong** · 05-28-2020, 10:31 AM

Originally Posted by tlwjkw

jus know one thing, they don't show on any parts list or drawings with '94 ta '97.. unlike tha nic motor list and drawings???.. but gettin' more n more dead cells............

Does not show them in the service manual either, shows them in the nic motor manuals. Wish I could remember if they were in mine when I cc my heads. But these days have a hard time remembering back a couple days.

Dave

**tlwjkw** · 05-28-2020, 10:37 AM

Tux mighta got one from a hung-over and/or over zealous line guy that day!.. only tha shadow knows for sure........

**Dave Strong** · 05-28-2020, 10:51 AM

Originally Posted by tlwjkw

Tux mighta got one from a hung-over and/or over zealous line guy that day!.. only tha shadow knows for sure........

Was just looking in the parts diag, they show diverters on ser# OG875000 and up but not below that.

Dave

**Bunger** · 05-28-2020, 10:52 AM

Anyone have any opinions on the spark plugs and exhaust chest being dirty/clean?

**tlwjkw** · 05-28-2020, 10:54 AM

Originally Posted by Dave Strong

Was just looking in the parts diag, they show diverters on ser# OG875000 and up but not below that.

Dave

are you tha SHADOW?...........

thats what happens when ya can only afford "old $hit!"

**tlwjkw** · 05-28-2020, 10:56 AM

Originally Posted by Bunger

Anyone have any opinions on the spark plugs and exhaust chest being dirty/clean?

don't know 'bout others but can't say without being able ta touch it.. would be justa guess!.. sorry..

**Bunger** · 05-28-2020, 11:52 AM

Can I use the .75 head gaskets I have after I pull the heads?

**tux974** · 05-29-2020, 05:22 AM

Dave you & Tommy are very sharp guys, extremely helpful here and with great spot on help, advice and info to all.

Dave, you are correct they did not for some reason put them in all the early motor especially 95 being the first year.
My guess is they for some reason realized in the later years they would help building heat so they started putting them in.
This winter I decided to put a few 2.5 200's for my RS and out of the 4 blocks and motors I got to build none had them and found it strange so knowing Tommy and Bobby TEXAS had worked on plenty 200's ask them about it and they confirmed that they did not come with them.

So I had a conversation with Marty @ Diamond and my machinist which both confirmed what I thought plus felt that it would help not hurt our application especially in the colder water we run, certainly in a 1pc application which I have been doing for years just like on all the PM's what I'm familiar with.

Forget things....did I have 1 or 2 cups of coffee this morning????......

BTW, has anyone checked the price of that 12" piece hose they sell to make them????........

Bunger, hard to answer your question. Has the block been decked? Have the heads been cut?
Standard gaskets on a PM are 1MM and the heads are 18789-C3 38CC's like a 260....you may already know this.
I got a few 200 blocks recently that someone decked and had to use 1.2MM gaskets and stock 18488-C5 heads to keep things safe with todays fuel.

**Bunger** · 05-29-2020, 06:11 AM

Originally Posted by tux974

Dave you & Tommy are very sharp guys, extremely helpful here and with great spot on help, advice and info to all.

Dave, you are correct they did not for some reason put them in all the early motor especially 95 being the first year.
My guess is they for some reason realized in the later years they would help building heat so they started putting them in.
This winter I decided to put a few 2.5 200's for my RS and out of the 4 blocks and motors I got to build none had them and found it strange so knowing Tommy and Bobby TEXAS had worked on plenty 200's ask them about it and they confirmed that they did not come with them.

So I had a conversation with Marty @ Diamond and my machinist which both confirmed what I thought plus felt that it would help not hurt our application especially in the colder water we run, certainly in a 1pc application which I have been doing for years just like on all the PM's what I'm familiar with.

Forget things....did I have 1 or 2 cups of coffee this morning????......

BTW, has anyone checked the price of that 12" piece hose they sell to make them????........

Bunger, hard to answer your question. Has the block been decked? Have the heads been cut?
Standard gaskets on a PM are 1MM and the heads are 18789-C3 38CC's like a 260....you may already know this.
I got a few 200 blocks recently that someone decked and had to use 1.2MM gaskets and stock 18488-C5 heads to keep things safe with todays fuel.

thanks for the reply

I know the heads haven’t been cut. I don’t believe the deck has been cut either. I ended up pulling the heads yesterday. Everything looked **** and span underneath. Put it back together with the .75 gaskets and fired it up. Still have 8-10psi at idle (1000) rpms. But it’s pissing water and building heat t stats are opening and closing so I’m just going to run it.

I typically run half av gas half 91 so I’ll be ok with the slight bump in compression from the slightly thinner gasket.

also there were nondiverters installed in the block. I did some research of my own and you are correct only motors with 1 peice plate and no stats and poppets have the diverters.