2000 promax 225 water pressure issue

**gsafe** · 12-08-2021, 08:21 PM

Freshly re built 2000 225 promax. During the break in period I seem to be having some water pressure issues. At idle im getting 1-2 psi and at fast idle slowly climbs to 4-5psi. The water pressure also fluctuates between neutral and drive while idling. However when getting from idle to 12/1300 rpm the water pressure climbs to 6-7 psi and then anything over that rpm the water pressure drops to nearly zero and then slowly starts to climb while getting on a plane. At 3500-4000 rpm the water pressure only reads about 4 with a broken to poor stream coming out of the pee tube. I replaced the impeller and thermostats were replaced by motor builder. Water temp has been between 140-155ish. While tuning at 3500-4000 rpm temp appears to slowly climb so I slowed down and you can see water temp drop to 140ish. Been hard to get pressures and temps while running under way since im still breaking in the motor. Poppet valve?? should the pee stream be a solid straight stream while under way?? thanks for the info

**25two.stroke** · 12-08-2021, 08:28 PM

You running a poppet or no?

**gsafe** · 12-08-2021, 08:36 PM

yes running a poppet.. I haven't taken it out to look at it yet as the boat is stored at the river 4 hours away

**Greg G** · 12-09-2021, 06:06 AM

Assuming the motor is completely stock and that you put in correct thermostats, I would start with the poppet and go from there. Use the search function on this site, there is a ton of info on Promax cooling.

**Dave Strong** · 12-09-2021, 01:01 PM

Do a full poppet valve kit, make sure the plastic insert in block is not loose or cocked in block.

Dave

**KIRCHNER** · 12-09-2021, 04:34 PM

My p-max gauge reads 150 ish all day.poppets do cause fluctuation on start-up & low speed range.

**Dave Strong** · 12-09-2021, 05:09 PM

Originally Posted by KIRCHNER

My p-max gauge reads 150 ish all day.poppets do cause fluctuation on start-up & low speed range.

Poppet should be closed untill over 10psi water pressure.

Dave

**gsafe** · 12-09-2021, 08:13 PM

Originally Posted by Dave Strong

Poppet should be closed untill over 10psi water pressure.

Dave

copy that. Sounds like I’ll start with a poppet valve replacement. Anyone have the part number handy for the kit? Thanks for all the info gents

**Mrzip** · 12-10-2021, 10:15 AM

Pro Marine can hook you up.

**pappa pete** · 12-13-2021, 07:10 PM

Make sure the hoses on motor aren't blocked, mine had the purdy blue fuel hose on the thermostats, the liner in hose closed off and burnt motor so check plz

**Baker343** · 12-13-2021, 10:01 PM

Are you running a 1 or 2 piece exhaust plate

**tux974** · 12-14-2021, 06:07 AM

Do you have a new complete water pump kit? Or at the bare minimum a new impeller.

**Mrzip** · 12-14-2021, 01:38 PM

Temp. On that PM can be tricky. Friend of mine burnt one on first break in trip

**gsafe** · 12-17-2021, 07:21 PM

Originally Posted by pappa pete

Make sure the hoses on motor aren't blocked, mine had the purdy blue fuel hose on the thermostats, the liner in hose closed off and burnt motor so check plz

I will replace those water lines as well. good call. also put in a new complete impeller kit. thanks for the info!