SX/SXi/SXi Pro 750, 1992. Mystery leak

[Mitcho4747]

When the ski is all put together, running condition, it takes on water FAST. bought it that way, with two bilge pumps in it....Okay, so I've gutted it, filled the hull up with water, and it won't leak out. I've taken it to the river, thrown it in, and it won't take on water!!! What!?! I'm currently replacing the bearings on the drive shaft going out to the impeller. Any other suggestions? I'm re silicone sealing the bottom seem back there too.

 

[way2manyhobbies2keep]

cracked waterbox or leaking fitting

 

[orangefinger]

shaft housing thru hull....that was like that on my first SX...

Or an incoming waterline is loose or leaks

 

[Mitcho4747]

Yeah, i'm re-doing the housing seals (housing itself as well as the grease bearings around the shaft).
I had planned on checking all the incoming waterlines, never thought about seeing if it's the water box itself!! Great suggestion.
There is a slight split, right where the main incoming waterline to the engine cooling system (big black one in pictures). So, i'm going to replace that hose and the old hose clamps too.
I've also taken my factory pipe apart and am considering replacing all of those lines just for the hell of it... they're black-dirty on the inside...
If anyone has any suggestions the popular water lines to go back with feel free to suggest!!! (otherwise, i mean, just any ole typical engine coolant lines will do right?)
I'll try to post better pics as i go back with the fixes.

 

[FlightPlanDan]

If the stock bilge system works like a Yamaha, (not familiar with kawi stuff post 1988), You could be back-siphoning. Been down this road with yama.
In a Yamaha system: there is a tiny pinhole in a plastic 90 degree fitting (above the water line) that, when clogged will cause water to rush into the engine compartment.
I believe I see this fitting in pic #3. It needs to be above the bondline to work properly. And the pinhole needs to be clear. It's tiny. A paper clip is too big.
You get the idea.
It may sound simple and stupid.....check it out.

 

[FlightPlanDan]

It's not an uncommon mistake. People look at this bilge line that goes way up only to turn around and go way down. In an effort to clean-up and make the engine compartment pretty, they shorten the line and keep it all low. This will not allow the system to function. It appears that you don't have nearly enough line to locate the 90 degree fitting above the water line. At least you still have the fitting!

Even though I'm a Yamaha guy, the more I look at it, I believe this could very well be your problem.

 

[FlightPlanDan]

Pic #2 shows all installed.
That fitting can not be located there. It will not pump water out, it will bring water in.
Stop tearing things apart and put a longer water line from the bulkhead up to the bondline, then the 90 back down to the suction chamber.
Easy fix for low $$$.

 

[Mitcho4747]

FlightPlanDan,
When I was standing in the hull of the ski, in the water, trying to see where a leak might be--> that little elbow joint with the needle hole did start peeing out water! But, for the amount of water that was coming in when the engine was in there, it didn't make since for that to be the main lead...Plus i assumed, when the ski is running that siphon suction would run the other way....
HOWEVER, i didn't have the sump all the way in the down position it would normally be in. (as in the end of the cable with the sump box on it was just hanging, about level with the T-joint with the pin hole)
I am definitely going to look into this. THANKS FOR THE TIP.

 

[FlightPlanDan]

FlightPlanDan,
When I was standing in the hull of the ski, in the water, trying to see where a leak might be--> that little elbow joint with the needle hole did start peeing out water! But, for the amount of water that was coming in when the engine was in there, it didn't make since for that to be the main lead...Plus i assumed, when the ski is running that siphon suction would run the other way....
HOWEVER, i didn't have the sump all the way in the down position it would normally be in. (as in the end of the cable with the sump box on it was just hanging, about level with the T-joint with the pin hole)
I am definitely going to look into this. THANKS FOR THE TIP.

The main source of incoming water is obviously not the pinhole.....it siphons all the way back down and enters thru the plastic suction chamber at the base of your hull.

If you want to test: block off the line thru the bulkhead and ride.

 

[Mitcho4747]

The main source of incoming water is obviously not the pinhole.....it siphons all the way back down and enters thru the plastic suction chamber at the base of your hull.

If you want to test: block off the line thru the bulkhead and ride.

RIGHT!!!!! ahhhhhhh this totally adds up too!!!!!!!

 

[FlightPlanDan]

Get a longer piece of water line, zip-tie that 90 with the pinhole up there near your electric bilge outlets and another longer water line back down to the plastic suction chamber. If this does not solve the problem, I'll pay-pal you the cost of the water line.

 

[FlightPlanDan]

BTW: You've got 1000 gal per hour of electric bilging + the stock bilge system ( pics don't show scuppers ) but your OP states that you got the ski this way.
It's unusual that a modded ski owner would keep the stock bilge and not opt to use the bilge line for dual cooling. This is a praise, not a criticism. I am a big fan of the stock bilge. If the motor's running, then it's pumping. Electric bilges are for when the ski gets away from you.

Scuppers are where I have a serious issue.

Unless you're a pro competition rider, you don't need them. Pros need to do a butt-load of tricks in a very short period of time, so they need the hull to empty out really fast.

The average rider puts them in because everyone has them and ends up buying scissor stands and other BS because a non-leaking scupper has yet to be invented, and when riding with your buds, you can just tool around until the bilge stops pumping overboard. ERRR! (just a peave of mine)

 

[Mitcho4747]

Put the ski in the water today, with the siphon down in it's regular position....to no conclusive results though.
It didn't poor water in like i was expecting to see. (however, it can still add up- because of all the factors of running the engine and creating suction, ect.)
That joint is almost right at the water level line..(just under it though) when you have the engine, gas, guts, ect. weight in there, it would be about an inch under the water line--i think.
You can see in the pictures water coming from the pin hole in the joint.
The test was pretty poor though...I stood inside the hull trying to add the weight but, you can see from the pictures that the joint is above the waterline in this test by about an inch... However, water was slowly coming into it after about 3 minutes.

The silly thing is though, i had already taken off the housing and bears around the drive shaft.. So, they're getting replaced/resealed regardless if that was the issue.
So, both potential leak areas are going to be fixed (and i won't be able to pin point what the source of the problem was --granted these changes fix it).



SO, when i get the rest of this ski back together, i'll be able to properly test things and get it solved the right way. I don't know if i'll get it done by Christmas though... We'll see, i'll keep posting updates and pictures as best i can.

 

[Vumad]

That siphon is still fairly low. It should probably be as high as that hull insert above it. That is likely the stock mounting location.

 

[FlightPlanDan]

It's gotta go up near the hood seal.

 

[FlightPlanDan]

http://partsfinder.onlinemicrofiche...?Type=13&make=yamahapwc&a=109&b=15&c=0&d=2004 SJ700B SUPER JET BILGE SYSTEM

Yes. This is Yamaha, but it works the same.

 

[Mitcho4747]

Here's the set up now. (it'll be another two weeks before i get to the water. BUT WHEN I DO, i'll post results)

 

[svtman]

That hole will not leak water in while the ski is running no matter how high it is in the hull. It just allows enough air to siphon from the bottom


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[svtman]

Fill up the ski then look for the leak


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[Blue]

I just went thru this on a kawi xi. Mine was the thru hull bearing housing. The rubber seperates at speed and water sprays in around the bolts. The rubbers should not seperate from the housing. Mine would push forward just enough to let water go thru.

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[Mitcho4747]

NO LEAK. (sorry it took so long, i cooked an engine and rebuilt, and turfed the back)
Getting the siphon to the correct height above the water line was the solution.

Thank to all, and special thanks to fightplandan.