Dont run without a waterbox

[trojoro]

So i bought my first superjet a couple of weeks ago and first time out it blew the waterbox apart so i thought i would just throw a straight pipe in its place just to get back on the water while i was waiting on the new box. After about 5 min of riding without a waterbox my engine came to a sudden stop. so i pulled the head and sure enough i hydro locked my motor...just my luck

the rod was snapped in half with little pieces of the rod floating around the motor, and it also took out about 5mm of one of the boost port.

 

[JamesG]

ehh.. yeah you need the waterbox

 

[Cliff]

doubt not having a waterbox did that. they are plenty of straight piped skis around here that dont have that problem. hell an xmetal box is almost like being straight piped. water injestion may have been the culprit though, like getting a drink through the carbs.

 

[trojoro]

is there any way to keep from ingesting water again? i have the stock single 44 mm flame arrestor and a 500gph bilge pump is there anything else i can do to help prevent it? i have almost $600 in rebuilding my motor already and would hate to have the same outcome

 

[kevbo]

If he rolled the ski from side to side without the engine running then one cyl could have took a drink. Single carb engines are less likely to hydro, they normally get both cyls wet enough to prevent starting. Once a rod bends it usually breaks in a few minutes.

 

[chad]

I have run without a waterbox for over a year now . loud as hell though

 

[tor*p*do]

those piston tops have lots of carbon
which suggest a lean running condition
that may the real cause of the failure

 

[Matt_E]

those piston tops have lots of carbon
which suggest a lean running condition
that may the real cause of the failure

Never heard of a lean condition snapping piston rods.

 

[Big Kahuna]

FOD

Looks like parts of the crank or cylinders on top of the piston.

 

[Big Kahuna]

Never heard of a lean condition snapping piston rods.

Get that bitch hot enough and have a hard seizure. Something got to give!

 

[Matt_E]

Oh please. Ever seen that happen?

 

[sjetrider]

the build up on the piston is most likely from poor oil quality , not lean.
no water box can very likely cause water intrusion and hydro lock. depends on what pipe you run as well. I would guess on a single carb with oem arrestor that the no water box was the issue here. Any interuption in the reverse flow of water in the exhaust system will help, even the x-metal. They have baffles in them as well as a larger open area to interupt flow.
Common sense tells you that a waterbox has a reason.

 

[kevbo]

I think most people just see it as a muffler.

 

[trojoro]

It was running the stock exhaust so I could see how water could make its way in the cylinder, I bought the ski a few weeks ago and that was the second time out on the ski, it realy sucks cuz I only got to ride for a few hours before it went kaboom.

And yes all of those little chunks of metal are from the rod,the sleeve and the piston skirt

 

[Sparkplug]

I ran no waterbox for almost 6 months of daily riding on my 650 sj. This is with wrecking, and the ski sitting upside, down sometimes, floating down current in the river, getting tossed all over trying to do hood spins, and it never hydrolocked, the only reason I have a waterbox now was because the sound got annoying. Stcok to the bone engine besides it had a aftermarket k and n, and i took it off cause it kept being a sponge, and now have stock.

 

[Austin]

This might be a stupid questions but Where did the water come from to make it up into the pipe? How would the water box helped it? I ran my x2 with a water box and My motor filled full of water twice last season but I was lucky because nether time it would start then I realized my motor was full of water so it never hydro locked.

 

[kevbo]

A waterbox should be designed with a build in stand pipe that is above the water line when the hull is on its side. Kawasaki 650sx and x2s have the outlet and engine exhaust on the left side so they made a tube that that goes to the far right side within the box. Some aftermarket boxes are missing this key feature. A Superjets design is not as good in this regard but few have problems with exhaust filling.

 

[egbrig]

You lose power without a waterbox. Sure it sounds like its making power but without the back pressure your losing power in the mid to upper rpm. Also why give people another reason to hate us. I always get a chuckle when some guy thinks his loud annoying ski makes "sick" power. A loud ski, sure sign of someone who knows very little about how it works.

 

[Matt_E]

Wise words as always Erik.

 

[Sparkplug]

My ski didnt come with a waterbox when I got it, neither did it come with a working start stop. I dont like the sound either, it is rediculously loud. Stock waterbox almost sounds like a electric machine now though. Need to find a comfortable medium. As far as power, Im gonna disagree with you. I feel with no backpressure, when I didnt have the waterbox, I had more top end, and less bottom end. Now twith the box, I feel less top end, but noticeably more bottom end.