Fuel Filter Change

LCDRChemEng · 11-06-2009, 03:13 PM

Is there a right way to remove the fuel lines from the fuel filter, other than muscling them out?
They seem to be pretty well stuck onto the metal tubes and won't budge.

kawiski · 11-13-2009, 06:08 PM

Filters on Kawi 4-stroke usually never needs a replacement. It's not even listed in the periodic maintenance chart of the manual. I've seen 200+ hour rental skis with the original filter. The only thing that needs to be chcked/cleaned is the pre-filter screen at the bottom of the fuel pump. What makes you think your fuel filter needs to be replaced? If you insist replacing, soak the fitting/hose with WD-40. Wait a little. Then try to push out with a flat tipped screwdriver. Don't pull on the hose. Instead, push.

LCDRChemEng · 11-15-2009, 05:35 PM

Quote:

Originally Posted by kawiski

The only thing that needs to be chcked/cleaned is the pre-filter screen at the bottom of the fuel pump.

The fuel pump was replaced earlier this year under warranty.

Quote:

Originally Posted by kawiski

What makes you think your fuel filter needs to be replaced?

The ski started acting up after a particularly long trip where I had to fill up enroute from a marina pump. After that, the ski (2005 STX-12f) would not rev over 6,100+/-. I replaced the spark plugs and verified the exhaust was not leaking, so I figured maybe the fuel filter was fouled. You are correct, however, the filter change made no difference, even though the old filter was full of filth.

I'm thinking the ECU for some reason has decided to limit the rpms. The engine sings lustily and pulls with no problem out of the hole, cavitation is non-existing, but the engine refuses to exceed 6k rpms.

Quote:

Originally Posted by kawiski

If you insist replacing, soak the fitting/hose with WD-40. Wait a little. Then try to push out with a flat tipped screwdriver. Don't pull on the hose. Instead, push.

You are correct again, penetrant did the trick.

shuswap · 11-15-2009, 10:44 PM

Has the verified speed changed? Tachs are pretty goofy on these things. I have the same ski. Min will indicate 7000 if I leave it long enough. Any idea if the 'filth' was able to pass through the screen? Or, has it contaminated the screen again? Only takes a few minutes if there is enough crap

LCDRChemEng · 11-16-2009, 08:06 AM

First off, thanks for taking an interest in this case, your input is always valuable and welcome.

Quote:

Originally Posted by shuswap

Has the verified speed changed?

Yes, the dream-o-meter previously indicated 58-59 (52 true), now it barely reaches 49 after a good run. The tach previously indicated 7K+ at top speed, now it will rise to one bar over 6K and stop there. Even more troubling, my wife's '05 GTX-4Tec now outruns my STX with ease. Not that I mind looking at her bum as she flies by, I just wish I could watch for more than a second.

Quote:

Originally Posted by shuswap

Any idea if the 'filth' was able to pass through the screen? Or, has it contaminated the screen again? Only takes a few minutes if there is enough crap

I drained the fuel tank completely and flushed the fuel system with Seafoam. I don't believe fuel delivery is a problem since the engine revs easily & smoothly, but it just refuses to go over 6K on the tach. Even when accelerating out of the hole, if I punch it WOT it will briefly run up to 6,500 RPM but then immediately drop to one bar over 6K. It will reach top speed while the throttle is halfway open and will not go faster.

I confess one time I was cruising the river over a real shallow area and not being able to see the bottom I wound up in water about 4" deep. I was iddling slowly watching the gators without realizing I was sucking mud when the temp sensor starter to beep. I was able then to steer to a deeper area where the clean water flushed out the silt. Once the water from the pisser was clear the ski ran normally.

I did, however, read somewhere that the ECU will remember overheating events and may be the reason why the engine is limited now. Does this sound like a possibility?

kawiski · 11-16-2009, 01:53 PM

Quote:

Originally Posted by LCDRChemEng

I did, however, read somewhere that the ECU will remember overheating events and may be the reason why the engine is limited now. Does this sound like a possibility?

Whoever wrote above is wrong.
ECU does not suddenly goes into limp home mode because it just remembers an old/prevous failure. ECU acts only upon current failure that exists now. 12F/15F has two reduced rpm operations that are controlled by ECU:
1. Limp Home Mode in case of existing/current engine malfuctioning conditions like overheating, low engine oil pressure, etc - signals from various sensors.
2. SLO (Smart Learning Operation) Mode - selected by rider.

Even if your ECU has a record of gizzilion stored failures, it does not affect the engine running condition as long as there is no aggrevating condtion now. Thankfully it's not like your credit recrod or FICA score at all - previous BK making you difficult to buy a new car or house

There are 2 possibilities:
1. ECU is somehow receiving a SLO signal when rider did not activate it. Possibility could be faulty dash meter, wiring/connection between the meter and ECU.
2. Engine problem (mechanical issue) - I would sugguest you check the engine compression. Whatever number (psi) you get, they must be within 10% (maximum) difference from each other. Personally I prefer 5% difference or less. If it is 10% or higher, remove the head and inspect the pistons. Or use a bore scope (if you can get one) for easier inspection.

LCDRChemEng · 11-16-2009, 09:51 PM

Compression gauge reads as follows:
1-135
2-150 (drops from 180)
3-191
4-130

Sounds like the head gasket and possibly the pistons and/or rings are fried. Bottom line a major rebuild is likely.

johnny5 · 11-16-2009, 10:00 PM

Bummer....good luck.

shuswap · 11-17-2009, 12:21 AM

Book say comp should be: "1 275 ∼ 1 795 kPa (13.0 ∼ 18.3 kgf/cm², 185 ∼ 260 psi) @430
r/min (rpm)"
Few thoughts:
Was the engine warm when tested? Was the battery good??....so it spun nice and fast?
If you take it apart now, it may not be as expensive.... as opposed to leaving it and having a piston let go.
How many hours on the motor?
Sorry about the lower numbers.......but I just had my near-new aircraft engine come up low on a leakdown test and that's even more expensive news.

Waaaaaaaaaaa!

LCDRChemEng · 11-17-2009, 06:26 AM

Once again, thanks for the feedback.
The engine was warm, but not really at normal operating temp. I will re-run tonight after several minutes on the hose. I did notice some cylinders held the top compression steady while others made the needle wheedle.

The battery is like new and hooked up to a minder so it was nice and strong.

I see a top end rebuld kit with pistons, rings, gaskets, and wrist pins for $450. Add labor and I guess I'm done (for). I concur, the ski is sidelined for now, don't want to replace the block too.