Only if you don't want to overheat the engine.

I will never own a boat without water and fuel pressure gauges.

my water pressure never goes above 13-15 psi, one engine runs fine 130* no matter how hard i run it the other eng is getting hot can't run it over 4k with out it getting hot. the one w/press gauge fluctuates and thats the engine thats getting hot. the engine thats getting hot runs 148/150* and climbs from there as soon as i run it over 4k rpm. the engine that gets hot has the p/s cooler thats the only diff between the 2 engines! ay ideas? thx ratman

Did You Change The Sea Water Pump? Do You Have A Stat?

I said it before I'll say it again, start diagnosing the problem.

The following will narrow it down for you.

Temporarily remove the power steering cooler (use a pipe) and test it. If no change, verify the pressure just before the exhaust (put a temporary tee in the line). If you have 15PSI there, then switch exhaust. If no change, you have an internal engine restriction, and you will need to tear it down, before you have a bigger issue.

i back flushed raw water plumbing. i yanked the p/s cooler today made a test pipe. took apart water plumbing going in to gaffrig mufflers. talked to mark at mer he said i don't have enough water presure 13 - 15 psi at wfo. how much pressure should come from raw water pick up? how much pressure should come from the raw water pump? no thermastat, new water pump housing and impeller!

here are pics of raw water plumbing

more pics

Over 35* at WOT. Stock 502 MPI's

Dont dump thru the mufflers that hole is way to small.

If you don't see the pressure rise after 3500rpms to WOT, your water P/U is too high. You should see 20psi minimum at WOT. Unfortunately you will most likely have to replace them unless you can add on. You can test this by adding some hose and switching the plumbing to the opposite water P/U's. If the problem starts on the other engine you have your answer.

BTW, the raw water pump does next to nothing at speed, it only really works at idle, when there is no water being forced in.