Other Sunk ski Question

Location
Michigan
I have a 750ss that sat at the bottom of a lake over 30' down for 3 months before we found it and could bring it up. I wanna use the motor for my 300sx build. The question I have is does anyone think the motor would be trashed? As soon as I got it out I drained the motor and sprayed it with WD40. It has been sittin on a shelf for a year now. does anyone think the crank would need to be rebuilt?
 

227

Its all about the surf!
Location
Oceanside, CA
After 3 months at the bottom of a lake and you sprayed it with WD40 did ya? well you're good to go then. A military jet crashed here recently and the clean up crew sprayed the entire site with WD40 and the plane took off and flew away!
 

yamanube

This Is The Way
Staff member
Location
Mandalor
After 3 months at the bottom of a lake and you sprayed it with WD40 did ya? well you're good to go then. A military jet crashed here recently and the clean up crew sprayed the entire site with WD40 and the plane took off and flew away!

LOL thanks for that!
 
Location
Michigan
Well lets see WD40 is a anti rust agent.If you spray it on rust and let it sit for a few the rust can be brushed off. There's no rust on the crank or the cylinders now after a year on the shelf. Thanks for the help. I answered my own question. By the way love the help ya can get on here at times. Its ether good info or a big wast of time.
 

IS0LD0UT

I hate winter
Location
MN
Doesn't it take oxygen to create rust? If it was sitting at the bottom and you coated it after... Could work. Im very interested in getting an update after you get it running.
 
For the price of gaskets and new crank seals. Brake the motor down check the crank, and everything else if its good put it back together, if not then you just saved your self a lot of hassle, and a sh%^y day when it blows. Fix it before that happens, trust me.
 
There are many different materials in an engine. As an example, lets look at iron...the main component of steel alloys.

Iron will rust or corrode (there's a big difference) but lets look at "true" rust: Iron will only rust in the presence of oxygen and a water-based solution (pH<9). Lake water is a perfect example of that solution, maybe with O2 levels up to 20ppm or so depending on plant life.
 

IS0LD0UT

I hate winter
Location
MN
I don't claim to know anything about materials or rust. Im just interested to if and how long it will run.
 
Location
Michigan
Thanks for all the info I planed on pulling it all apart and putting all new gaskets on it. the ski was over 30' down and it was sunk in muck up to the bars. There were no plants any where neer that ski. It was in the high 80s the day I went to get it. The water down there was freezing at the bottom of the lake. It was crazy how cold it got at the bottom.
 

227

Its all about the surf!
Location
Oceanside, CA
Lee I apologize, the answer to your question is so obvious that I thought you were making a joke. There is no such thing as a noob/stupid question. The serious answer is, Sorry that motor is trashed. Water ingestion damage starts to occur in as little as a few hours, even in fresh water, so a motor that's been submerged for over 3 months =history. Could you get that motor to run? Most likely the answer is yes but how long it will stay together is another story. As already mentioned, the issue is the bearings. Jet skis, or any other type of motors have precision fitted surfaces on the crank and needle bearings that need to withstand rpms of up to 7500. That's a lot of forces working in a motor so even the slightest bit of damage not visible to the eye will cause a motor to come apart. WD40 is a rust inhibiting lubricant, but it can't repair damage that's already occurred, even damage not visible to the naked eye. The drain plug on a Kawasaki is there to facilitate water removal from the crank IMMEDIATELY after it was sunk, and was not intended to be used several months down the road. A ski which has ANY kind of water ingestion in the motor needs to be cleaned out and started within hours of its sinking to avoid damage. BTW guys water DOES have Oxygen in it, Remember H20? (2 hydrogen molecules to 1 Oxygen molecule) and metal DOES get rust damage when completely submerged
 

chad

I pretty much love beer
Site Supporter
Skywalkers boat sat at the bottom of the lake all summer till it was found ...AND THEN IMMEDIATELY TAKEN ALL APART . I think he replaced the crank just to be sure. but everything else was just fine .
 

Vumad

Super Hero, with a cape!
Location
St. Pete, FL
Unless you can add gas and make it run, replace the crank. It'd be foolish to spend the money on a top end and try to save money on replacing an obviously bad crank. Yes you can run it. It could be just fine, but the probablyity of failure is extremely high. Remember it's not just an issue of destroying your brand new top end. A failing crank can very easily send metal bits out that will most certainly destroy the head and put large gashes into the cylinders. Worst case it could crack the cases, which will make your partially rebuilt (instead of correctly rebuilt) motor into scrap metal.

Buy a crank or part it out as a core and buy a running motor.
 

brett

-------------
Location
Ventura,ca
even a slight rust on the bearings will lead to crank failure. when the rust come off it leaves tiny craters on the ball bearings themselves and that cost me a set of 62t cases when they failed....new crank at least
 
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