High water pressure & low water temp

[transomstand]

I really wonder if I don't have some sort of parts issue?

No question about it, it's the big black part on the transom that's the problem

[transomstand]

I guess I really need to go out and run the crap out of it, stop really quick and then IR it.

Don't you know some kook who would hang off the back at 90 mph for you?

Sorry......... just remembered Jeff's going out of town this weekend

[Sonik]

Keep it up Pete, I might just show up at the Romp with a new interior color.

[njj502]

$hit you are going to be lucky to get your ass out the door with all your crap and find a place for the ole lady to ride out east.

[rock]

He will be prepared.

[jaybluez]

Guys, this winter I put my ProMax back on a 2pc plate, put the poppit back & the t-stats. When I first fired it up in the water my PSI was fine & no temp. I expected this as the water here was only 42*. When I got the chance to actually run it the water was probably 45*. Fired up backed off the trailer and everything was good. Idled around a bit and the stats opened about 145*. Pressure never changed... took off and wham, buried the water pressure gauge and the temp gauge fell way below 100*.....

I'm lost.... How can high pressure also create low temp? Also note that I changed the water pump cover and feed tube from 3/4" to 1/2"..... I think I got all the right gaskets...... are any of the adapter gaskets from the mid up to the powerhead different between a 200 2.5 and a ProMax 225?

I had the same thing happen to me several years ago. I had never determined what caused it. Prior to pulling the powerhead everything was normal but after reinstalling the powerhead I experienced what you are describing. The only thing I could come up with was that I used an aftermarket powerhead base gasket instead of the merc gasket. I truly believe if you didn't buy a genuine merc gasket that may be the problem. I don't recall the part# but I bought all my parts from a local shop and I never had a problem. On the last installation I bought them online to save a few bucks and that's when the problem started. The gaskets were made different also, the merc gasket I used in the past was always metal reinforced. The one I bought online wasn't. I don't recall if they were identical as far as matching ports, water passages, etc. Maybe something to think about.

[texasvector]

just gonna keep this going with my issue since I'm dealing with a 225 promax on a 2 piece plate.

before the rebuild I had good water flow out restricted t stat housings. running a poppit valve. water pressure around 10-12 wot.

I wanted to go back factory plumbing so after the rebuild I installed 143 t stats.

here's my issues.... on the hose or in the water I'm not getting any water flow out the t stats..... whether they're installed or not ( I pulled the t stats to see if I was getting water it the heads)

on the hose water pressure is 2-5lbs..... out on the water same at idle and increases with throttle.....8 pounds on plane..... up to 12-15 with throttle punches. ( haven't been over 3000rpm for more than just a punch). to me water pressure seems normal. on the hose I've pulled water pressure hose and poppit line from top of block and both have steady stream.

I have a temp gauge reading head temp just below #2 cylinder. on the hose it holds down low.... on the water up on plane it comes up to about 145-150 ish.. and cools of when I drop to an idle..

I've replaced water pump and housing.... replaced seals at top and bottom of water tube. checked all gaskets in mid and exhaust divider plate.

heads seem ti be holding water.... enough to cool but not enough to exit through t stats.

I have the tale tell fitting on top exhaust plate blocked trying to push more water up.

I've pulled popit hose off plugging top and bottom while on hose.... still no water coming outta heads.


I'm stumped.... or stupid. please help!

[transomstand]

I'll assume you've checked the pump tube itself for any leaks. Install water pump base 44292A3 and only use genuine Merc stuff for the impeller and cover. What kind of gearcase setup do you have?

[texasvector]

if by water tube you mean copper tube.. then yes I've inspected it with new seals to and bottom. if you mean something else on gear case side then no.

I haven't replaced water pump base.

I purchased impeller and housing kit from local merc dealer. not sure on part number. gear case is from a 1991 v6 135hp. coned with Bob's cone

[transomstand]

Try that base, it has a smaller bleed hole and should raise your pressure all around. Sounds like you pretty much covered everything in the powerhead, so I'd be looking at the water feed side of things.

[texasvector]

k changed water pump base out. left t stats out. ran on hose... still no water at idle. soon as I bump the throttle both heads pee. right now if I run t stats I d ont have a tell tale. gonna go put it in the water and see what the pressure does... with t stats in.

if everything looks good I m gonna run a tell tale from exhaust plate out the side.

I'll be back in a bit

[texasvector]

well here it is.... at idle there's just a trickle out of starboard t stat. got up on plane at 3000rpm water pressure reading 8#. temp gauge comes up to 145 ish and h olds there. at this speed there's a nice flow outta t stats.

brought it up to 5000 and saw 15# on pressure gauge. look like it would of kept climbing up to WOT.
the new water pump base definitly got me more pressure.

now to figure out if or where to run a tell tale. it scares me to idle around with no water coming out.

should I drop to 132 t stats? just cruising today. temp never ran above 150.

Pete do you have a tell tale dumping out starboard side??

[transomstand]

Yep, mine is all stock

[Sonik]

Sorry to leave you hangin' last night Cody.....I owe ya one....

[transomstand]

well here it is.... at idle there's just a trickle out of starboard t stat. got up on plane at 3000rpm water pressure reading 8#. temp gauge comes up to 145 ish and h olds there. at this speed there's a nice flow outta t stats.

brought it up to 5000 and saw 15# on pressure gauge. look like it would of kept climbing up to WOT.
the new water pump base definitly got me more pressure.

now to figure out if or where to run a tell tale. it scares me to idle around with no water coming out.

should I drop to 132 t stats? just cruising today. temp never ran above 150.

Pete do you have a tell tale dumping out starboard side??

Pressure is still low. I just read back through some, I don't see much about the poppet, are you sure it's not hung open? That would keep your pressure low.