2010 Kawasaki JetSki STX-15F Overhaul - First Ski

[mdmay62]

It's been a while and not a ton has been accomplished. I've been working on building up some funds to keep building. This week I was able to get a new impeller in and finish the pump rebuild.


I am still also working on getting the broken spark plug threads out of the head. I may end up pulling the engine and doing a rebuild soon just to get the spark plug free. If anyone has any suggestions to get the threads of a spark plug out of the head hit me. The threads are all that is left the electrode came out along with the first 1 or 2 threads it broken off just below the nut.

[mdmay62]

Well a short winter break and some home improvements and I'm back to working. Since the pump rebuild I've been working on the engine and a few other things. First off, I finally decided to drill out the spark plug so I pulled the top end of the engine out of the ski and cleaned up the head. Next I pulled the cylinders, cleaned them up and sent them out today for re-plating, hoping to have them back in 6 weeks. Today I also got the drive shaft out in preparation to replace the driveshaft seal and bearing. I've been working on waxing/polishing up the hull as well trying to get that looking better. I'm almost ready to put the stabilizers back on. Finally I got some rivets to reattach the right rear corner bumper and a new nose bumper to install as well as a new kawasaki deck decal.

[steve45]

I put that blue marble HydroTurf in my blue Yamaha Exciter boat. It looks awesome!

[mdmay62]

I put that blue marble HydroTurf in my blue Yamaha Exciter boat. It looks awesome!

I do love the way it looks on the ski, not what I was planning on at first but happy I wen that route!

[mdmay62]

Still waiting on the cylinder to come back so I've been slow moving on some other stuff. Last week I ordered a new intake grate since I broke mine trying to free it up and yesterday with a little convincing and heat I was able to get the broken piece off.


I tried to use the same method used to restore the stabilizers on the reverse hood however it was not a success so, I decided to throw some paint on that as well to make it look new again.



I was also able to get the hood painted to the new scheme, I'm not super happy with the way it came out but it will do for now until I know I can get it running, I'll recoat in the offseason to get it looking perfect.



I started cleaning up the hull inside since I have the engine out and I was able to rebuild the driveshaft bearing/seals. On order I have new piston rings and a gasket kit so when the cylinder returns I can jump right into the rebuild.

I'm also trying to find the best way to get the white out of the black bottom, if anyone has a good trick to this, I'm open for suggestions!

[mdmay62]

I was just poking around on here recently and found a thread that almost sounds like my situation to a T, hopefully it is piston rings like this. It was a little worse for me though because the Nikasil was coming off the cylinders so they needed to be replated.

Post number 22 gives similar compression as to what I was getting when I did the compression test.

[mdmay62]

Well I just finished up with my engine rebuild. Cylinder was welded and plated, installed new connecting rod bearings, pistons, piston rings, all new seals and gaskets. Cleaned and lapped all valves (these were stuck but were working by hand when done with the clean up). Went to do a compression test today as my first step in testing the rebuild and I am getting 62 psi on all 4 cylinders so I'm looking for some advice here. Could timing be off even after following the procedure in the manual? Could a bad battery lead to this? I pumped out as much old gas as possible and filled with new so it might be a slight mixture of good and bad gas although I did put stabilizer in it before the winter. I think it is strange that even with a rebuilt engine I am getting the same low compression on all 4 cylinders at the same time.

It turns over but it sounds like it turns over a little slow and of course gets slower as the battery weakens. I don't know the age of the battery or how it was kept before so I am going to grab a new one tomorrow yet just to be safe even though I don't think this is the cause.

[steve45]

Compression gauge, perhaps?

[smokeysevin]

Did the engine turn over smoothly by hand? You can feel the cam lobes when you turn but it should not take significant effort to to.

Clean all the battery and ground wire connections and clean where they attach to the starter motor.

It is really easy to get the cam timing off. When I do these motors, I set the timing, install the tensioner, then turn the motor over by hand 2 or 4 full crank rotations by hand and check the timing again. The timing can look fine before installing the tensioner but if you aren't careful, it can slip a tooth or if you install the wrong side of the cam chain first as your reference tooth.

Sean

[mdmay62]

Compression gauge is borrowed from someone at work and they just it ok so I'm inclined to think it is OK.

[mdmay62]

Did the engine turn over smoothly by hand? You can feel the cam lobes when you turn but it should not take significant effort to to.

Clean all the battery and ground wire connections and clean where they attach to the starter motor.

It is really easy to get the cam timing off. When I do these motors, I set the timing, install the tensioner, then turn the motor over by hand 2 or 4 full crank rotations by hand and check the timing again. The timing can look fine before installing the tensioner but if you aren't careful, it can slip a tooth or if you install the wrong side of the cam chain first as your reference tooth.

Sean

So, I didn't have a good stand during the rebuild and when I went to turn it it just wanted to fall over so I passed on that which is probably a rookie mistake. I feel like the timing might have slipped a tooth and that is what I'm dealing with. I am doing the quick and easy first, new battery since I don't truly know the condition of the one I bought it with.

Gut feeling though is cam timing, how hard is it to do in the ski? I'm trying to avoid pulling the engine again so soon. Thanks for your advice.

[smokeysevin]

So, I didn't have a good stand during the rebuild and when I went to turn it it just wanted to fall over so I passed on that which is probably a rookie mistake. I feel like the timing might have slipped a tooth and that is what I'm dealing with. I am doing the quick and easy first, new battery since I don't truly know the condition of the one I bought it with.

Gut feeling though is cam timing, how hard is it to do in the ski? I'm trying to avoid pulling the engine again so soon. Thanks for your advice.

You will need a mirror and probably an inspection camera. It is a massive pain but possible.

Sean

[mdmay62]

You will need a mirror and probably an inspection camera. It is a massive pain but possible.

Sean

Sounds good, thanks, I'll try to give that a try this week.

I tried the new battery and still doesn't start, I didn't try to do the compression test again though to see if any change happened.