225 promax with one piece adapter plate

[tux974]

Look at the stainless base plate in the cowl. Its all closed except at the popet area. This is how merc made it work... mount the wrong pan and you are in trouble.

Correct! But the poppet dumped in the are those holes would dump it did not dump into a poppet like cavity which it did or does not exist.
Idea was to keep/slow down dumping water in the block to build heat. You also want to get a bit of water around exhaust ports.
Why next best thing if you do not have that plate modding the adapter plate dump holes was the next thing to do in order to achieve a similar situation.....and if pressure was high then release/dump water out of the poppet hose in a controlled manner to help achieve desired temp and pressure.....my 2 cents and what I have done to make it work....I'm finito!

[bigboy]

I know this is an old post but This is what i saw on my 225x short shaft when i pulled the power head last night. Maybe it will help someone. It has 120 degree thermostats and a poppit valve.

Hi, can you post the diameter of these dump holes? Are there any other (small) dump holes in the adapter? Is there one at the right top and blocked with dirt?

Thanks!

[Ramm2012]

no problem, i will check that out when i get home tonight and let you know. I still have the engine off at JSRE being rebuilt

[ProComp]

Just did a 225 promax with washers, gutted popped, reduced holes to 17/64, its running 150 degrees head temp. Pretty sure the pan is stock 225 promax

[Ramm2012]

Hi, can you post the diameter of these dump holes? Are there any other (small) dump holes in the adapter? Is there one at the right top and blocked with dirt?

Thanks!

They are 3/8”only 2 holes Hope this helps

[NZ Sidewinder]

I've got a 225 fish promax and an offshore one piece midsection in the wings.
My plan is to race the fishing leg 2 piece inshore and work out how to get the one piece to work before diving in.
Reading everything I'm thinking that a new laser cut cowl base is needed without the dump holes.
This creates a large poppet cavity that is ddrained to atmosphere via one route or another.
Then in the middle of the blanked off base plate is a 90 deg barbed fitting that is hanging in the now huge poppet cavity but drains to atmosphere via another route or another.
These atmospheric routes may be used to cool the pump or tuners .
The drain holes in the one piece would all be plugged with the exception of the one that vents the poppet.
The size of this poppet drain hole in theory is irrelevant as it is simply a vent serving the poppet.
The leg could be technically dry stacked.
I like the idea of using an olive fitting with a piece of ss tube through it feeding a water jet at the pump.
It has occurred to me that at high speed there may be enough surplus flow from one of the low water pick up tubes to supply water pump cooling.
Just my ponderings to date.

[NZ Sidewinder]

Would this work Popey?
This is a rough sketch of a one piece that would go under a pan plate with no dump holes in it.
The dump chamber would have both drain holes plugged and act as part of the poppet gallery.
I haven't actually had a close look at those large plugs in the side of the one piece yet and am assuming I can get them out.



An olive fitting would be tapped into the side of the one piece and pipe poppet discharge water around to those large threaded holes in the side of the one piece and using olive fittings pass through those plugs and into elbows tapped into the exhaust ports.
This pipework and elbows would be submerged in, but sealed from the incoming cooling water.
IMO this replicates the two piece system.

[PanRonnie]

i tried to recreate the sst 200XS engine which has steel sleeves
closed of the holes in de base plate with washers , so water will have to exit through the poppet
i did drill out the mid plate holes to 4 times 7mm
buit the top hose is not connected to the poppet cover it has it,s own exit now
the poppet cover is also an exit now ( lower blue line ) and the thermostats are in going into the light blue line
the 200XS is weaker than the promax 225 poppet spring ,so i used the 200XS spring (stock 200 spring ) more flow
you can now regulate the top drain to give more or less water having some control over ti

[NZ Sidewinder]

So do you mean that the poppet is dumping into the cavity that has the 4 x 7mm holes and the exhaust is dry?
Im not sure what you mean that the poppet cover is an exit now?

I learned from steam turbines that the best way to get more power from a turbine without adding more steam is to quench the exhaust vapor because as the vapor cools it shrinks in volume reducing the exhaust chamber pressure.
This creates a larger pressure differential across the turbine and more power. ??

Tonight Ive created a Cad drafting file that a CNC laser cutting machine can follow to make those Pan plates without the large holes on them.
The same drawing is used more or less in a CNC gasket cutting machine so will get both done.
Ill do the whole thing in gasket paper first as its cheaper and when its a good fit the laser cutter can do the stainless plate.
The gasket part is easy but creating the outer shape of the pan plate is not easy because its sort of a free hand shape.

[PanRonnie]

my mid plate is till the same as this with only 4 holes of 7mm instead of 2
this still enters into the exhaust housing
only instead of water coming from the the top to enter the poppet covers it now works as an overflow so surplus water can exit out of the poppet cover and out of the cowling

i did a test today as i changed my rpm signal from the tacho pulse to a 36-1 tooth pattern
you can see it,s a cold start from the head temps of the engine EGT 7 and 8
they later go up to 136 and 116 this is at idle unloaded

[NZ Sidewinder]

Thats cool.
I did struggle to read the number labels though as they are a bit small in the video.
Are there 4 EGT signals?



My plate is different than yours next to the exhaust ports
Also my plate has oval ports for an oval port tuner
I hope this isnt a deal breaker.
I dont have the big hp tuner and was going to use a square promax one??

Added some stuff
These are screenshots of the files that CNC machines will use to cut new Pans and gaskets

[PanRonnie]

with the base plate cut like the 200SST or as you are planning it does not matter what is underneath 2 piece (will dumpt into the poppet hole) 1 piece (will dump through the mid holes)
i would use the original high performance gasket as that has somekind of reinforcement in it (think metal gaas)

here is the youtube link you can zoom or slect the picture quality
https://www.youtube.com/watch?v=yDa15RKDA64

[NZ Sidewinder]

Thanks.
So you run your exhaust tuner dry?
I've just removed 5 broken tuner bolts from a dry stacked one piece plate and also need to get the tuner gasket face milled as it had blown through the web between the ports.
I like to see some water going down that route now.
Dry stacked racing cooked it badly.
So I guess it's just a matter of balancing the flow from the poppet some goes to the tuner.
I'm thinking 3/16 copper tube which will flow not much.
Then maybe tap those two existing dump holes to 3/8 pipe so they can be jetted experimentally.
I'll talk with the gasket maker as to what materials he can use.
The machine uses a razor to cut and can cut a 2mm hole in 0.8mm hard paper but probably not in reinforced paper.
Water jet cutting would cut the good paper though.
For example a standard gasket out of the US here in nz is 35 bucks but 65 bucks freight.
4-6 weeks delivery.

[PanRonnie]

no i still have the water entering the midsection through those 4 holes in the midplate
i have a stainless tuner so guess that would not be a problem but having your midsection heat up and possible become weaker is
i am not into racing and unlimited budget so i have me some water in it

[NZ Sidewinder]

Wow.
Must have been some budget for that tuner.
Is the round lip designed to dampen harmonics?