2.4 200 HP High water pressure 45 PSI

**slpcamaross97** · 06-12-2019, 03:27 PM

Originally Posted by transomstand

When you pulled the powerhead did you split the exhaust plate? The lower half could still be full of sand. Also you would want to pull the divider plate and check the passages to the block, junk loves to get caught in there.

I have pulled and split the exhaust plate(Thinking that this is the plates that hold the upper motor mounts too?)

What is this Divider plate you talk of? is that for the exhaust divider plate that is in between the cylinder heads on the back side if the engine?

**nitro_rat** · 06-12-2019, 03:30 PM

Originally Posted by slpcamaross97

What is this Divider plate you talk of? is that for the exhaust divider plate that is in between the cylinder heads on the back side if the engine?

**slpcamaross97** · 06-12-2019, 03:33 PM

Originally Posted by nitro_rat

Thanks for the heads up. Yes i did have that off and cleaned it out. BUT, that was before i found the midplate full of sand and rocks. So im going to pull it tonight and re check all the passages possible.

Gaskets are cheap at this point. Im about ready to condem the powerhead and try to find another 200hp powerhead.... which does not sound easy.

**Merc 2.5** · 06-12-2019, 03:49 PM

200 easy come by. When he said split the plates , u should had have to remove the mounts ,and it's a 2 piece plate , u gotta b missin sumthin sumwere, try it with stats completley removed

**slpcamaross97** · 06-13-2019, 12:05 PM

Took the exhaust cooler assembly apart again last night. Zero debris. Ran wire though each cooling passage that i can see.... all is nice and clear.

Removed the complete mid section and all the plates.... zero blockage found.

**FMP** · 06-13-2019, 12:33 PM

Chuck of something in somewhere, old pump . Pull the heads yet?

**transomstand** · 06-13-2019, 12:39 PM

A few more things. In the lower half of the exhaust plate on the starboard side there is about a 5/16" hole that shoots water into the poppet cavity that isn't readily apparent, double check that it's clear.

I'm also pretty sure you said you have a 1st design poppet. On a mid 80's 2.4 you would actually have a second design using a round 2 bolt cover. May want to double check you have the right parts in it. You can also verify poppet operation watching the gauge. At about 16-1800 rpm you should see a pronounced drop in pressure when the poppet opens (usually about 10 psi or so).

I would also swap hoses on the pressure gauges to keep them "honest". Hate to see you knocking yourself out over a gauge gone goofy.

The only other I'd check right now is with this engine history of sand intrusion, I'd want to look at the water pump base to confirm the bleed hole is the correct size and you don't have something imbedded in it. That can have a fairly dramatic effect on pressure.

That's about all I can think of at the moment. I'll let you put it all back together then think of something else you should have checked

**FMP** · 06-13-2019, 01:04 PM

Bleed hole!

**slpcamaross97** · 06-14-2019, 11:56 AM

Originally Posted by FMP

Chuck of something in somewhere, old pump . Pull the heads yet?

Yes, Head pulled along with the cyl head water chamber covers externally. Super clean! zero issues

**Dave S** · 06-14-2019, 05:27 PM

If you run it with out the poppet cover..... and it still has too much psi.....prob in block. And it will water ya garden. From what I read you put a hose on the copper tube..... garden prs... 9 lbs and still had too much when running? head gasket seal.......2.0 gasket .... on a 2.4? seen it.

**slpcamaross97** · 06-14-2019, 07:40 PM

Originally Posted by FMP

Bleed hole!

Where is this bleed hole in the lower water pump base?

**slpcamaross97** · 06-14-2019, 07:43 PM

Originally Posted by Dave S

If you run it with out the poppet cover..... and it still has too much psi.....prob in block. And it will water ya garden. From what I read you put a hose on the copper tube..... garden prs... 9 lbs and still had too much when running? head gasket seal.......2.0 gasket .... on a 2.4? seen it.

I had the poppet valve in place when running it on the garden hose. And yes the garden hose was attached to the copper pipe in the mid section.

Head gaskets were factory oem never been replaced before. I installed oem gaskets.

Thanks for the tips though.

**slpcamaross97** · 07-01-2019, 12:39 PM

Just posting a update.

At this point, i have taken everything in the mid section apart. I have found two water passage holes blocked with sand. The first one was in the bottom of the mid section- Right by the "exhaust can". My feeling is this is nothing more than a drain and not part of water flow out of the powerhead.

Second plugged hole was in the lower unit right in the area of the water pump. This hole would drain water into the exhaust area. Also my feeling is that its more for water draining out of the mid section/around the pump.

Third area i found was more of a possible leak. But in the lower motor mount area, was a hole(from a previous bad motor mount) that was sealed with epoxy. might have been a "ok sealing"... but unsure. I had this damage welded up(water tight).

The water pump bypass hole in the lower water pump base is clear and open.

**slpcamaross97** · 07-01-2019, 12:45 PM

Other strange thing that may or may not be a issue was the mid section to mid-plate perimeter gasket was missing/not installed. Along with the exhaust tuner gasket was missing and all 6 bolts were loose(my guess is maybe low torque on the bolts allowed the gasket to be pushed out overtime).

Im slowly putting it back together now. Unsure of what the results will be. But I've covered everything i can.

Also putting in new plastic poppet valve waters(Was not replaced on prior repair attempt), and all new poppet valve parts(again).