Corrosion

[steve45]

Kawasakis seem to be more prone to corrosion problems than other brands. It has caused me problems on several 'Skis this season, and I thought I was doing a moderate job of fighting it.

I primarily boat in a freshwater inland lake, but the water is brackish. This is because I live in the heart of oil & gas country and saltwater is a byproduct of oil & gas production. There are some ponds where produced saltwater has been collected over the years and one of the dams of a salt pond broke years ago and the salt flowed downstream to my lake. I'm not sure if the problem is actually due to salt or something else. I plan to get a sample of the lake water and have a local lab analyze it.

I do not flush my 'Skis after each freshwater outing because the mobile home park where we have our lake house gets pretty upset if you use water outside. Also, the salt flushing products are expensive and hard to get (my last order from Amazon took 5 months to get). I DO flush at thoroughly at the end of the season and follow up with a good dose of Marine & RV Antifreeze.

I'm going to try a couple of things to solve this problem. I'll probably flush more often when I think I can get away with it, or flush with antifreeze. I'll blow out the cooling system with compressed air to try to dry it. Finally, I'm going to try coating the cooling passages with epoxy paint.

Here are some recent examples of the corrosion that I've found:

4-1 exhaust pipe from an Ultra LX:



Cylinder from an Ultra 150:



It turns out that all three of my Ultra 150 cylinders have pitting in the same spots, (front & rear of the cylinder) but only one has had a break-through. We're going to repair all of them. The exhaust expansion chamber also has several new leaks. It had 14 pinholes a couple of years ago. I've only got about 30 hours on the engine since a top overhaul a couple of years ago, so I hate to break all the gaskets. It was running so well... At least I won't have to replace the rings since they're pinned. The water pipe seems to be in fairly good shape, but there are a few pits inside of it.

Here is a 4-1 pipe that I recently painted with epoxy and installed on an LX:

[TimeBandit]

Heating, cooling, water, galvanic currents, etc - repeat ... it a constant battle.

Sometimes painting (or coating) parts can backfire on good intentions. Its all about the galvanic issue. The part will never remain 100% coated with paint, so the tiny unseen bits of exposed bare metal then concentrate/focus the electrical currents to those very spots, accelerating corrosion like a laser.

Do Kawis have anodes on/in the block? Ever considered DIY adding more. Local marine store has tons of various sizes, etc... some can be bolt on various parts if you have an imagination. For example, I have a small one attached to a jet pump bolt, one on the inner side of my ride plate too, where I tapped a small bolt.

Rinsing : I read advice here long ago about using Dawn soap to flush. I have to say... it's been working out great so far. I bought saltaway kit once (has the flushing accessory). Now I refill that flusher with half Dawn & half water. Very economical.

Another strategy that has served me really really well - Fluid Film. LOL - leave it to sheep to come up with something natural and extremely effective against water. It is "messy" (liquid wax), but works! Like Frank's hot sauce - just put that sh#t on everything, metal, rubber, plastic - keeps everything preserved by blocking water and more importantly air exposure (both being source of oxidizing O2). Like paint, it's going to offer that barrier, yet unlike paint it "self-heals", aka any re-exposed metal, given you keep a liberal amount applied, will wick the film back over itself.

[pro1200]

Your post is timely as I just fixed a severe case of corrosion on my '15 STX-15F that is used exclusively in salt water. My conclusion is that there is nothing an owner can do to prevent it because of stagnant water that remains in the cooling system. I am the original owner and flush with Salt-Away after each use. Unfortunately I don't have pictures but here is what I found after 6 years and 200 hours of use:

-The 4-1 collector was rotted through
-The oil cooler was almost completely blocked and rotted from corrosion
-The exhaust manifold passageways were almost completely blocked
-The coolant pipe located under the intake manifold had some corrosion

As a comparison, I also run a '17 Sea-Doo RXT-260 that has 490 hours used the same way and have never had a cooling system issue. This is mainly because the cooling system for the engine doesn't circulate raw water. Unfortunately the Kawasaki just requires more maintenance.

[steve45]

Good to know. Thanks for your input!

[Rescue1]

Just curious as to why said trailer park won't let you use outside water? I know in my area when there is a drought we usually have different stages of same and Marine maintenance is listed as an allowable activity.

[steve45]

We're in a drought, an exceptional drought. At least we have some water left in our lake, but it's down about 15 feet from 2 years ago.

No hot tubs, no lawn watering, vehicle washing, etc.

[smokeysevin]

I have seen failures in the same spots as you, as well as the stator cooling cover.

Dawn and water is my go to for flushing. Squirt a bunch into the port then turn the water on.

No anodes in the kawasaki skis.

The biggest issue I see on the kawasaki setup is that there are lots of locations for water to just sit and corrode with no good way to dry or empty the passages.

Coatings all flake off eventually, I have never seen one that truly can take the heat cycles of an engine, submersion in water, erosion, seam lifting or scratches, and salt.

Sean

[steve45]

There are some industrial coatings that we use in the oilfield that will hold up (except for the heat on the exhaust manifold). However, I don't think you could clean a used part well enough for it to stick. New parts would probably work fine, but the coating process is rather expensive.

I'm leaning toward trying to blow the system dry with compressed air.

[thudd3rski2]

wonder if a coating like jet hot would help...at least on the exhaust parts. i have used them on motorcycle exhaust a few times, but nothing that comes in regular contact with water (just rain). it holds up well and they claim it stops corrosion. price is decent, or at least it was the last time i had it done years ago

[smokeysevin]

Here, thermal expansion is the biggest issue. If those coating will work on aluminum it might help. Like Steve said though, biggest issue is getting them to stick properly and on used parts you are sol.

Sean

[steve45]

OK, I've come up with a potential solution to this problem. We actually got some rain at my house, almost 2 inches over a couple of days. I had some large plastic tubs so I tried to see how much water I could catch. I was able to fill the 25 gallon tubs very quickly. I found some 275 gallon IBC totes for a reasonable price, so I picked up 4 of them. For now, I'm going to try to catch water at my house and transport it to my lake house. I used a 12 volt bilge pump to transfer the water into the totes. I tried flushing a 'Ski with the bilge pump, but it really wasn't up to the task. I'll have to buy a more powerful pump.

Eventually I hope to install some rain gutters at the lake house and just collect water there and not transport it.

[Mentzel]

Kawasaki castings are horrible to begin with, then add to the fact the skis use open loop cooling.. Kawis are NOT designed well for salt water use. Salt water literally melts raw aluminum so you must flush every part that comes in to contact after every ride.

Salt away works! I have soaked manifolds with heavy salt deposits in a bucket of salt away and they cleaned up well. I used a half bottle in (5) gallon bucket left it for (3) days. However if the metal has corroded away it wont fix that! But salt deposits will be gone.

[Mentzel]

Also note that 4/1 pipe you coated looks great but has sketchy pock marks near the water passages on the gasket surfaces. Those details could destroy an engine if the gasket leaks water from the jacket into the exhaust. The water jacket is under full jet pump pressure. Water and hot exhaust makes steam, steam will create excessive back pressure creating cylinder detonation. Then holes in pistons from heat / detonation.

[steve45]

Also note that 4/1 pipe you coated looks great but has sketchy pock marks near the water passages on the gasket surfaces. Those details could destroy an engine if the gasket leaks water from the jacket into the exhaust. The water jacket is under full jet pump pressure. Water and hot exhaust makes steam, steam will create excessive back pressure creating cylinder detonation. Then holes in pistons from heat / detonation.

Thanks for the input. I supposed I could mill it down a little bit and clean up the pock marks.

[Mikes1200STXR]

Hey Steve, how many hours were on those Ultra150 heads? Surprised to see it actually corrode through! I gave mine a thorough inspection when I had the engine out but didn't see anything abnormal...some slight seepage from a few gaskets but nothing major.