Dumb cooling question 1997 115TJEUC

Hi,
I have a 1997 115TJEUC engine (OMC sterndrive). 4 cyl, 2 cycle, water cooled, mated with a TurboJet propulsion.
A couple of weeks ago the engine conked out after about 10 minutes running flatout.
I determined that it had shutdown due to overheating. (restarted a couple of days later and checked temps with IR probe. Port side was 200+ hotter and engine shut down again). I changed the thermostats/relief springs/valves etc. (YES they are positioned in the right orientation) Water appears to be pumping fine (when checked last week).
Strainer is clean. (now....but it was half filled with sand /silt) I re started and let the engine run at idle for approx 30 minutes. Temps on both sides were the same. Engine shut down and I checked temps on plugs/heads were close to 450. My dumb question is "does the drive need to be in anything but "neutral" for water pump flow?"
(I don't remember when I checked the water pump before (at output of strainer) if I had goosed the throttle forward with the boat secured)
Any ideas for possible flow restrictions or otherwise would be appreciated.
Thx!!

Those units were only marketed for about 4 years.-------------The first step to do is a compression test !-----Then perhaps look at the " water deflectors " in the block.----------heads need to come off to look at them.----Motor must idle in nuetral in the water at around 1200 RPM for proper cooling.-------I do not believe there is a seperate water pump on those, and cooling water comes from the main propulsion impeller.

Racer,
Thx for the info. Checked compression as suggested. STBD side (with WOT and both plugs pulled) both at 125-130 psi. (comparable to last time I had checked a couple of years ago). PORT side 45-50. Ended up pulling head . Gasket is blown.....visibly.....metal ring toast on one cylinder. Rest of gasket as well as cover gasket gonzo.
I didn't know what you meant by water deflectors until I am just looking at parts diagram. I had noticed one rubber "plug" at the bottom cylinder jacket. Thought it was debris at first. Didn't look for another. I am two hours away from boat so can't run out and take a peek lol. Should the second deflector be 180 (exactly opposite?) out from the one I noticed on the bottom cylinder?
Thx

You had best find a picture of how they go in there.--------Critical to get this correct.-----Might as well have a look on the other side too.-----------Resurface the heads with some emery paper on a piece of glass.------I know that your heads are not flat right now.

Figure 8 on that glass till same color and texture appear on entire surface of head using 220-400 grit or higher.do it right the first time!!

OK You beat me to it. (grit) Thx to both of you for the help. It has been quite some time since I have seen the top of a piston or crank. (autos usually).
Waiting on parts.....and weekend. thx

keep us posted as to progress with your project

Thx guys. Success Cleaned all surfaces as recommended. New gaskets.....water deflectors (funny....well not really....there wasn't one installed in upper "position" as indicated in diagrams referenced. Assume that is how it came out of factory based on bolts/paint etc) plugs etc etc. Head torqued per specs/sequence. Started engine. Idled for 20 minutes. Temps at covers near plugs...140ish. Let things sit for an hour or so. Re started and took it out for over an hour. Putt putt and WOT....re starts.....all good. Will re check bolts/clamps etc. next visit. THX!! again.

Make sure you retorque cylinder head before using engine again. Some times they loosen up slightly after warming up

Yup. I should have used that phrase when I said "re check bolts/clamps"
THX!!

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