225 promax with one piece adapter plate

[Steve Pope]

If you add up the area of 4 1/8 drain holes it adds up. You only need 2 holes. you actually can get away with 2 3/32 holes for drainage.

[bigboy]

If you add up the area of 4 1/8 drain holes it adds up. You only need 2 holes. you actually can get away with 2 3/32 holes for drainage.

Ok, what holes would you close off? The one next to the exhaust openings or the ones in the front?

No risk of tuner melting or melting water pump?

What size do you drill through the popet cavity?

Thanks!

[Steve Pope]

We usually run the holes in the front to drain when engine tilted. There is plenty of water SPAYING into the exhaust housing while the popet is closed. Also, the egine is not making much power and so not much exhast temp until above the rpm that the popet opens and dumps all the cooling water into the exhaust housing.

[bigboy]

You mean the exhaust spray because the 2 holes? Or is it the line from the top to the popet cover spraying plenty water.

I closed the holes at the rear. Will take it out on sunday. Hopefully all good now.

[transomstand]

You mean the exhaust spray because the 2 holes? Or is it the line from the top to the popet cover spraying plenty water.

I closed the holes at the rear. Will take it out on sunday. Hopefully all good now.

Did you enlarge the poppet hole?

[bigboy]

Did you enlarge the poppet hole?

I left that the same.

[Greg G]

You mean the exhaust spray because the 2 holes? Or is it the line from the top to the popet cover spraying plenty water.

I closed the holes at the rear. Will take it out on sunday. Hopefully all good now.

Did you tap the rear holes and plug them or did you permanently close them off?

[bigboy]

Did you tap the rear holes and plug them or did you permanently close them off?

I tapped them. I used set screws first time with holes drilled through. Now just inserted a bolt in the rear holes to close them off.

It makes it easier to experiment. I will fill with epoxy afterwards and drill through.

[bigboy]

So I tested today. Didnt make a lot of difference.

The 2 holes to drain are more like 7/64.

Normaly when I start engine up and let it idle it will heat up and the T-stats will open.

The temp needle goes a bit up and thats it. I just plane off and warm it up at 2k. Engine temp is about the same as with the 2 piece plate once on plane and to WOT.

The T-stats never open. Just a tiny flow from the bleed holes in the stats.

After fast runs when I idle it starts cooling down. Needle about in the middle of cold and first mark.

I also noticed I have a lot of water steam coming out of the mid. Mostly at higher rpm. I think this is because the tuner is very hot and one the popet opens water hits it and epavorates? I think the popet dump is just above the boss of the mid where the block studs go through. So the dump water hits this wall and water gets sprayed all over inside.

I added a picture. You can see the white smoke. It also comes out of the hole above the bottom joke where normaly a U bracket is mounted...

I'm stumped why it's not heating up at idle!

I run a 2hole cle and a mercruiser water pump base because the 2 hole cle is known to melt waterpumps when using stock pump base. I ran this same setup of the 2 piece plate.

[Capt.Insane-o]

My HST had the same water vapor trail behind the cowl. It cost me a couple Motors. I had to close the air holes in the rear of the cowl and spaced the front plate out an inch to keep the cowl from investing water. With a 15 inch mid it wasn't nearly as bad, So there is something particular about the airflow around the back of the boat. After a long high speed run water would run out the rigging tubes when slowing down and drain all over the top of the gas tank.

[Go Time]

What size poppet drain did you use?

[bigboy]

What size poppet drain did you use?

3/8" which is the same size as the hole that is standard drilled in the pan steel plate.

[bigboy]

My HST had the same water vapor trail behind the cowl. It cost me a couple Motors. I had to close the air holes in the rear of the cowl and spaced the front plate out an inch to keep the cowl from investing water. With a 15 inch mid it wasn't nearly as bad, So there is something particular about the airflow around the back of the boat. After a long high speed run water would run out the rigging tubes when slowing down and drain all over the top of the gas tank.

Did you motors ingest the water in the horn? I took my cowl off when arrived at home and saw some waterspots in the inside on the pan...
So there must have been some spray inside.

What holes did you close of? The very small ones at the very rear / backside or those at the top?

You spaced the front plate so it would capture more air?

I have a drag cowl copy. No holes at the backside of the cowl. My front plat is spaces a bit and the intake hole is a lot larger.

I notice the water mist is there too at some lower speeds... And also at top speed it can vary...

[bigboy]

Lynn, Here is a picture. Just when taking off. The mist is is not from high speed.
I think it's once poppet opens water sprays on the hot tuner and the mist is the result...



What I can try is just close of the idle relieves. Thus no mist can exit the offshore housing?
Can I just close these off? My previous offshore leg had no holes drilled in the relieves. With the 2 pieces plate exhaust could relieve through it. I used another housing which has holes drilled at the inside because with the 1 piece plate there is no exhaust relieve via the adapter.

My snout is blocked off for noise. I do like the merc sound but the people around here not that much

[transomstand]

3/8" which is the same size as the hole that is standard drilled in the pan steel plate.

My Promax pan is the full triangle cut. But don't go gettin any ideas, if the temp is good at speed, don't mess with it.