2006 Kawasaki STX 12F blowing oil filter gaskets

[Jwaring]

I recently purchased a 2006 Kawasaki STX 12F. The engine has 170 hours and no visible corrosion. It has near perfect compression and idles great. The problem is when I run it on a hose it will idle fine. As soon as I rev the engine it will blow the oil filter gasket. I have replaced the original Kawasaki filter with a K&N and a Super Tech. In each case I have had the same result. When the gasket blows oil it is gushing at the rate of about a quart in ten seconds. I believe this problem is being caused by a stuck oil pressure regulator or a blockage in the oil line somewhere. Before I was having this problem the jetski was making white smoke and the exhaust had unburnt oil in it. I was told this was caused by having too much oil in the engine which was removed and replaced with the correct amount and weight oil. I am stumped and looking for advice for how to proceed.

[nmpeter]

I'd bet you have a second filter gasket stuck on the crankcase. Since you can't really see it feel around for it with the filter off. Its a common reason for gasket blow offs

and welcome aboard.

[Jwaring]

Thanks for the response. I should have mentioned that I checked the gasket mating surface and took a video of it to confirm it was clean.

[TMiller]

At the time when you ran it with white smoke and oil in the exhaust was it blowing filter gaskets then? Can you get a picture of the gasket after it has blown out?

[Jwaring]

No. It didn't start blowing the oil filter seals until after the oil was replaced with the correct amount. Not sure if this helps but I have never run this ski in the water and have never had a chance to open it up. So far i have only idled the ski with the ocasional rev of the engine.

[nmpeter]

Thanks for the response. I should have mentioned that I checked the gasket mating surface and took a video of it to confirm it was clean.

yeah, providing those small details save diagnostic time and replying with useless advice.

[nmpeter]

so moving along...

how much oil did you add? ( 5 qt typical)

was the hull level when you added it? ( don't guess, get a builders level)

measuring the oil pressure is a pain in the ass

https://www.manualslib.com/manual/782436/Kawasaki-Stx-15f.html?page=184

changing the relief valve requires engine removal, an even bigger pain

given the tasks at hand here's what I'd suggest

pump the oil out, should be between 4.5 and five quarts

add back 4 quarts of oil and 8 oz of marvel mystery oil, idle the engine on the hose for 5 minutes at a time with a ten minute rest between runs, you don't want to overheat the jetpump, give it at least a half dozen cycles.

On the last two cycles, slowly run the engine up to 2500 rpm. Then stop the motor and prepare for the possibility of the gusher when you start it up and rev it to wherever the oil starts blowing around. Perhaps a plastic bag taped to the filter will help contain some of it, but if it does blow, a little oil mess is the least of your problems. Next step is removing the manifold and tapping into the oil system and if you confirm excessively high pressure, then you are pulling the engine

with some luck the relief valve is stuck and the marvel oil will help persuade it to behave

I don't envy you on this one, that is some messy and tiring crap to deal with

Might as well check the engine compression also, in regards to the previous ( or perhaps impending) failure of the engine

there is a possibility, not knowing anything about the history of this ski, that a previous engine failure resulted in some shrapnel that got into the oil sump and not cleaned out, and the tiniest flake of aluminum can stop the relief valve in its tracks

good luck to you sailor, you're going to need a boatload of it to escape this whirlpool of badly behaved lubricant

[Jwaring]

Thanks for the detailed reply. The only good news is that I know the history of this ski. It was owned by a older friend of mine who rarely exceeded 35 mph. He told me that the last time he tried to crank the ski in preparation for a trip it was hard to start. Life got in the way and the ski sat for over four years in his garage. I have no reason to not believe him and his story checked out because The first thing I had to do was have the pump rebuilt due to being stuck.

[Jwaring]

[Jwaring]

I got the filter off and the face of the filter was bent. Could this be due to high oil pressure?

[DealsGapCobra]

It looks like there is a dent in the side of the filter. And chance something is moving when you rev it and hitting the filter?

[steve45]

No, not due to pressure. Did you use an oil filter wrench to install it? Be careful not to damage the oil pressure sensor.

Also, make sure that you're running the correct filter! Kawasaki changed filters over different model years.

[dlsauder]

Did you figure out your issue? I have the same thing on my 07 Ulta LX.