I have a 4 stroke 115, 2013, changed prop last year after hitting rock at low speed, engine will run under 3000, Oil had water in it , changed the oil, water is back

compression pressure is read at cranking speed with throttle wide open. For petrol engine it is 155-165 psi hot dry with an allowed variation of no more than 10% between adjacent cylinders and around 175 psi hot wet (OIl injected to seal rings)
For a diesel engine it can be 550 psi -650 psi hot dry at cranking speed with the only engine being test while running being a detroit diesel 2 stroke
There is no compression reading done at rpms as it is meaningless

Hello Kit,well its the end of the season so if your really handy you need to change your prop and housing ring , the gap gets bigger over time and your jet prop gets smaller in diameter, letting high force water just pass by, just did the two of mine last year,same thing and now there like rockets!!!!!, cost =110.00-150.00 in parts , if dealer does it add 150.00 or so

I have had this happen when cylinder head was warped causing oil under pressure to enter coolant. hope this helps.

1. Check your oil level. If oil level is not ok, correct oil level and find out why oil level was low and correct the problem. (Leaks, bad PCV, Burning oil due to severe engine wear, nobody has bothered to check it for the last 3000 miles, WAY overdue for an oil change, etc.) If oil level is ok, proceed to next step.

2. Remove the oil pressure sensor and install a manual oil pressure gauge. Run engine to verify low oil pressure. If gauge shows that the oil pressure is low, overhaul or replace engine. If oil pressure is ok, replace oil pressure sending unit and retest.

Hello: At the time your owners manual was printed the oil change recommendation was 7500 miles, BUT that was under ideal driving conditions. (NOBODY drives a car under those conditions) If tour car has a four cylinder engine I would recommend between 3,000 to 4,000 miles. I have a 2001 Saturn with 202000 miles, bought new, use Castrol 10W30 Castrol oil have changed it every 3000 miles my self and have records to prove it. The engine still does not use or leak any oil.

Engines are like us humans. The better care they get the longer they last
\Change the oil at every 3000 to 4000 miles and do the preoper suggested maintenance by Fords outline in their manual for a long life
I own a 2000 Mountaineer with 190000 miles. It still runs like new although the body is starting to rot
The oil is changed every 4000 or sooner
Tuneups are done at 65000
Suspension is checked every year

Check for loose heat shields the cover the exhaust. I find this is the source of many rattles. They are made of sheet metal and if they are not clip or tightened down the low vibration frequency when the car is running at slow speed will cause them the hit the exhaust pipe/ front mainfold.

If you are close to 3000 miles, change oil. Low oil will overheat and change chemically. While under there, take a look around and see where or if oil is leaking anywhere (should not be hard to find) After changing, run and check again while running. Providing you aren't getting a lot of smoke out the back, (burning it) likely you will find a leak, then fix it!
good luck

That is just condensation. Usually if you have a cracked water jacket you will get white smoke out of the exhaust rather than raw water\\

Drive slower and easier. about 1 or 2 BELOW THE SPEED LIMIT DON'T PASS ANYONE . When you accelerate accelerate nice and easy watch the tachometer try to keep it below 3000 rpm all the way up to your cruise speed nice and easy don't worry about the guy behind you . Brake easy if you are coming to a light take your foot off and coast and try to time the light so its green when you get there. then EASY EASY on the gas keep it under 3000 RPMS all the time you are accelerating.
No special oil no special spark plugs or fancy air filters just factory parts whren you tune up every 3 or 4 years and change your oil about every 3 or 4 years yes 3 or 4 years it wont hurt it a bit just remember to always check the oil and add if it gets 1/2 Qt low. change the fuel filter EVERY EVERY 15,000 MILES fuel injection professional pressure cleaning once a year Air filter when it is dirty, please dont believe all those gimicks out there I have a car we change the oil about every 4 years and it has 350,000 miles no engine work yet runs every day passes emsssions every year no repairs needed fuel filters once a year or 15,000 miles