Tracking an Exhaust Leak

[Techfan85]

So I definitely have an exhaust leak, decent amount of smoke in engine compartment when run with hood off. But I can't seem to find the link, any suggestions? I already pulled exhaust apart and checked couplings, no issues, all very pliable, clamps are on super tight. Suggestions? Thanks guys.

 

[Mike W]

Run it while attached to a flush kit. Should be easy to run down. Look at the water box as well. It may or cracked or failed somewhere.

 

[Techfan85]

Run it while attached to a flush kit. Should be easy to run down. Look at the water box as well. It may or cracked or failed somewhere.

So I know its Christmas, and I am out of town next week, but ran it today hooked up to a hose and I just get lots of smoke, looks like its coming from everywhere haha. Any suggestions on how to start tracking it down? I means it might be everywhere from b pipe to water box. Thanks and Merry Christmas all. Will be back 1.1 and update then.

 

[Mike W]

So I know its Christmas, and I am out of town next week, but ran it today hooked up to a hose and I just get lots of smoke, looks like its coming from everywhere haha. Any suggestions on how to start tracking it down? I means it might be everywhere from b pipe to water box. Thanks and Merry Christmas all. Will be back 1.1 and update then.

What kind of ski is it?

 

[Techfan85]

Backie chan, has a b pipe, then an exhaust manifold to what appears maybe a custom water box? Didn't have this issue before. But after riding it in the surf several times something has gotten loose and damn if I can find it. Took it apart, inspected all rubber pieces, put it back together, now worse haha!

 

[Tyler Zane]

It's likely the coupler or waterbox, like Mike said. Water should be leaking aswell as smoke. If you can't see it leaking your just gonna have to tear it apart again and inspect it closely. Pressure check the waterbox too.

 

[Mike W]

My money is on the water box. I bet it has a crack or it failed at a weld.

 

[Harbor]

We pressure tested the exhaust system with a had pump and soapy water, just like you would an engine. Expandable pluming pipe plug in the tail pipe, plug the pissers and disconnected hose, presurize it via the water fitting at the stinger, spray soapy water. Keep in mind pressure will back up the water injection points and get back in the cooling system, so pressure will leak out your pump if not pinching off or disconnecting the incoming water cooling lines

 

[Tyler Zane]

We pressure tested the exhaust system with a had pump and soapy water, just like you would an engine. Expandable pluming pipe plug in the tail pipe, plug the pissers and disconnected hose, presurize it via the water fitting at the stinger, spray soapy water.

So what did yall find? Did you plug the chamber at the coupler end? Or i guess you could use some rubber with only the three bolt holes sandwiched at the head pipe to block the engine side.

 

[stefan]

Will it with water

 

[Harbor]

So what did yall find? Did you plug the chamber at the coupler end? Or i guess you could use some rubber with only the three bolt holes sandwiched at the head pipe to block the engine side.

We found a soot trail at the exhaust hose outlet at the bulk head pipe, the clamp was not tight enough to seal and would start to leak some with the ski in water, easier to come out the clamp than blow a bubble under water I guess. It was tested completely assembled, no block off's installed, cap water injection spray bar and we let the reeds seal off the case and ran a hose pulse nipple to pulse nipple. Tnt v3 pipe set up.
On a b-pipe you could cap the two water nipples on the head pipe to block injection back flow or close the adjusters off, ( if they seal completely) block the pulse nipple, plug the tail pipe, presurize via the stinger water in line

 

[Harbor]

Tzane, it may be best if the op replaces the head pipe gasket with rubber to seal off the engine like you mentioned. We did a traditional engine pressure test and then a cooling system pressure test followed by the exhaust pressure test so it's possible the rubber was still
Below the carbs.

 

[Tyler Zane]

Tzane, it may be best if the op replaces the head pipe gasket with rubber to seal off the engine like you mentioned. We did a traditional engine pressure test and then a cooling system pressure test followed by the exhaust pressure test so it's possible the rubber was still
Below the carbs.

Lol, for a few i thought you did this pressure test on the OP's ski. In your first post you said "we did" and I thought you where talking about him.

I was just wondering what the working pressure of a crankcase was to figure a safe pressure for the reeds, but i personally wouldn't wanna subject them to it. I agree blocking off at the head pipe with a solid rubber blockoff would be best. Then all you really need to do is run the bottom head pipe fitting to the top fitting and pressurize at the stinger like you mentioned. OP, a cheap bike pump with gauge would be perfect for this. Id say 10 psi should be plenty.

 

[Techfan85]

Thanks guys. Out of town currently but will mess with it when I get back and update. Appreciate the input

 

[Techfan85]

Well found it, weld has busted at a joint in water box completely along a corner that I couldn't see well enough last time due to turf. Thoughts on rewelding it (I can't weld aluminum) or should I just purchase new? Any thoughts on which one to go with if replacing? Set up is 735 62t cases, 61x top, exhaust manifold & head pipe bored out, b pipe. Pics attached. Thanks guys, and happy new year. First pic was from pictures when I bought it just to give you an idea of box & set up, second is with a flashlight in back to show the exhaust "mod"

 

[Harbor]

It can be welded good as new. Usually they pop at the weld on a backfire.

 

[Tyler Zane]

Hell ya, weld that joker up

 

[Techfan85]

Okay dudes, update: got it welded, ran it a few times, but now its blowing gaskets off the b pipe mid section or today it popped off the water box (water end) and damn near sank. So is it possible that I have too much pressure in the system or maybe the waterbox has a failed baffle in it? I personally tightened the hose clamps A TON, and the dang b pipe has a lip on it, but it still popped loose. So now I am wondering if maybe the system has too much pressure on it. Runs out of water, but when you put it in water it has been popping gaskets loose. Any advice? Its 2" exhaust system, no idea manufacturer, its b pipe-> coupler elbow-> straight 2" pipe-> coupler elbow-> short pipe-> coupler-> water box-> exhaust piece.

As always, thanks!!!