Griff

My 502mpi's have pretty high water pressure also, but not at 3500rpms. I run about 20psi at 3500 and at WOT, they will push 35psi. Its higher than I like, but in 530+ hrs, has not created any issues

If the water presssure is that high, I doubt you have much debris/impeller pieces stuck. If I get any sizeable debris, it gets stuck at the entrance to the oil cooler and my water pressure drops about 10-15psi.

abmotorman

It all depends where the blockage is. Lower pressure would mean before the gauge pick up tube (usually found before the thermostat in the intake manifold). Higher pressure would indicate after the pickup. I.E. thermostat housing, exhaust manifolds and/ or risers.

As a FYI only, I never see over 12 psi. on mine.

MILD THUNDER

iTrader: (3)

Looks like all the starboard gauges are a smidge higher than the port. Water temp, oil temp, and oil psi. Could be a weak ground behind the dash.

In regards to the temp though, looks like they are running in the 180 range water wise. I believe they should be 140-150 with the merc thermostat?

Rookie

iTrader: (4)

I had a similar problem on a little different setup. (crossover w/ bypass) Port engine ran 170*F and starboard ran 160*F. To solve my problem I had to restrict my bypass a little to allow more water to flow through the engine. This increased block pressure a little but cooled the block. So what I'm trying to say is don't just concentrate on water delivery, but also water exiting. Thus a little bit higher water pressure on that engine. Flow is the inverse to pressure and flow is more important than pressure unless you have to much pressure.

Also, check your grounds.

Rookie

iTrader: (4)

Dam! you mild!! I guess great minds think alike!

Griff

502mpi's use 160* Tstats and mine will run between 165-175 on the guage most of the time and up to 180* after a hard run.