High water pressure 225 promax

**Bunger** · 05-24-2020, 10:32 AM

Been chasing this problem for the last few weeks.

Ran the boat in January everything was fine.

Ran it on the hose in March everything was fine.

2 weeks ago did my yearly water pump/gear lube/filters ect to get ready for summer and fire it up on the hose and had 14 psi at idle. Pulled t stats they opened at 143 on the stove. Pulled poppet it all looked fine figured it was the hose pressure causing it. Drop it in the lake and it was idling at 13 and getting 25+ at wot. Definitely seemed to be running rich and cold by the soot on my prop. Also was barely dribbling water at idle.

brought it home replaced t stats with inverted units recommended by jay smith. Replaced poppet valve assembly dropped lower looked at water pump all looked fine.
put it al back together fired it in the driveway and was pissing water like normal but idle pressure was still 8-10 and woulnt drop till I revved it. Dropped it in the lake yesterday had 6-7 at idle in gear 10 in neutral and most I saw at wot was 23. Seemed to run fine definitely not overheating. Heads felt evenly warm. Telltale water was warm. Not sure if I just have a kick ass water pump or something else? All lines are clear. Poppet dump passage appears to be clear. Replaced base gaskets and exhaust divider gaskets last year.

Any ideas because I’m out of em.....

only thing I haven’t tried was cutting a coil or two off my poppet spring

**rock** · 05-24-2020, 11:07 AM

High water pressure is often plugged dumps in the adapter plate especially if you have a low water pick-up.

Rock

**Bunger** · 05-24-2020, 11:14 AM

Originally Posted by rock

High water pressure is often plugged dumps in the adapter plate especially if you have a low water pick-up.

Rock

Welp it looks like I’m going to be pulling the powerhead then. And yes I have a sport master

**tlwjkw** · 05-24-2020, 11:18 AM

if ya go ta doin' things that aren't supposed ta be done ya probably gonna "mask" any problem ya havin'...

its a little over borderline with those pressures sounds like ta me.. know some that would kill ta have that kinda pressure!.. why they would, i don't know.. its performin'/runnin' right?.. not gettin' hot that ya can tell?.. what did it read last year?..

**Bunger** · 05-24-2020, 11:21 AM

Last year it was 3 to 5 at Idle and 15-ish running it hard.

**tlwjkw** · 05-24-2020, 11:26 AM

i'd be doin' some lookin' around also then............

**kct11** · 05-24-2020, 12:26 PM

Went through the same thing. Pull powerhead and clean adapter plate.

**perfmarine1** · 05-24-2020, 01:43 PM

Check your gauge, is it going back to 0 every time? What did the old water pump look like?

**Bunger** · 05-24-2020, 04:48 PM

Originally Posted by perfmarine1

Check your gauge, is it going back to 0 every time? What did the old water pump look like?

gauge appears to be fine. I just bought a pressure/vacuum gauge to check it against my gauge I’ll check it tomorrow. Old water pump was a year and a half old and didn’t look too bad at all. I’m super ocd about not dry starting and keeping the lower out of the sand but last summer my jack plate broke and I tagged a sand bar cause my motor was hanging so low but I ran it 5 times since then and never had an issue.

**Bunger** · 05-24-2020, 04:48 PM

Originally Posted by kct11

Went through the same thing. Pull powerhead and clean adapter plate.

eas yours clogged with debris or hard water/calcium buildup?

**half fast** · 05-24-2020, 06:16 PM

Check to see if the plastic sleeve that is pressed in where the poppet slides in and out may have moved out a little . It MUST be even with the block . Hf...

**Bunger** · 05-24-2020, 06:22 PM

Originally Posted by half fast

Check to see if the plastic sleeve that is pressed in where the poppet slides in and out may have moved out a little . It MUST be even with the block . Hf...

I checked it. It’s solid and peened in place. And I think if it was crooked I’d have low pressure.

**Promaxin** · 05-24-2020, 08:03 PM

Had the same problem with mine a few weeks ago and it was the poppet. It had a non genuine poppet valve in it which was slightly different to the one I got from merc. Started again with completely new poppet kit with the grommet and it sat further into the block, also noticed the poppet spring that came out of the promax had a lot more coils (stiffer) than the poppet that I pulled from a 2.5 200. Things to check anyway before pulling the powerhead. Mine was doing the same 25-30psi at 4k rpm and around 12-14 at idle.

**Bunger** · 05-24-2020, 08:14 PM

Originally Posted by Promaxin

Had the same problem with mine a few weeks ago and it was the poppet. It had a non genuine poppet valve in it which was slightly different to the one I got from merc. Started again with completely new poppet kit with the grommet and it sat further into the block, also noticed the poppet spring that came out of the promax had a lot more coils (stiffer) than the poppet that I pulled from a 2.5 200. Things to check anyway before pulling the powerhead. Mine was doing the same 25-30psi at 4k rpm and around 12-14 at idle.

interesting.... weird cause I had the same poppet in it for 2 years. The new one was an off brand (go marine) I believe. Going to run it with on the hose with 2 coils cut off the spring. I have a complete gasket kit so I’ll probably pull the powerhead regardless