Super Jet leak down test question

[SXIPro]

Dumb one: I've leak tested my sj engine in the past while it was still in the hull and plumbed. If I throw it on the bench to leak test it, I'm guessing I need to plug the cooling line on the exhaust Mani that runs to the pump and plug the cooling line in the head?

 

[hydrostyler]

Nope. You've got problems if you need to plug your coolant lines to get a seal. Just block off the intake and exhaust manifolds, leave the plugs in, and monitor pressure through the pulse line. I can't tune motor for sheit, but I can verify when they are sealed. I'm sure someone will chime in to back me up or blow my theory. Haha

 

[SXIPro]

Nope. You've got problems if you need to plug your coolant lines to get a seal. Just block off the intake and exhaust manifolds, leave the plugs in, and monitor pressure through the pulse line. I can't tune motor for sheit, but I can verify when they are sealed. I'm sure someone will chime in to back me up or blow my theory. Haha

That's what is confusing me. Block off the exhaust manifold,yes, but end there is an open brass elbow screwed into that. Or is the elbow screwed into a enclosed channel or something inside the exhaust Mani?

 

[DAG]

How much of the exhaust mani is on? If you have all the way to headpipe you will need to block off the cooling circuit

 

[just joe]

No need to plug that cooling brass fitting, you are pressurizing the intake/fuel path, not the cooling path. Yes, it's a separate circuit.

 

[hydrostyler]

brass fittings should be for the water inlet on the exhaust manifold. If your gaskets are good everywhere, those chambers should stay separated and not leak. Put a few lbs of air in and watch your gauge. Get your soapy spray bottle ready if seems to be leaky.

 

[DAG]

pressure test your cooling circuit. It should also hold air.

 

[SXIPro]

I need to stop drinking and wrenching. Of course its a separate circuit. Doh! Pay no attention to the guy polishing off a handle of Captain Morgan. Thanks for the help.

 

[Quinc]

Make sure your spark plugs are tight. Had to tighten mine with a wrench so they wouldn't leak..

 

[SXIPro]

Make sure your spark plugs are tight. Had to tighten mine with a wrench so they wouldn't leak..

Thanks. And this might sound completely random, but would you mind pming me your shoulder workout?

 

[Vumad]

That's what is confusing me. Block off the exhaust manifold,yes, but end there is an open brass elbow screwed into that. Or is the elbow screwed into a enclosed channel or something inside the exhaust Mani?

The coolinb jacket in the manifold is not connected the the exhaust gases. The cooling jacket in the head pipe injects water so it is connected.

You do not need to block the cooling fittings on the manifold. i think most peole remove the head pipe, but if you leave the head pipe on, you need to block the cooling fittings on it. The head pipe has 2 fittingz so just connect them to each other.

 

[Lumpy]

I always pull my headpipe off, put a piece of bike inner tube over the manifold, then reinstall headpipe to get things air tight. Works like a champ in my experience. Same thing on intake side. Remove carbs, insert thin piece of rubber over intake runners, reinstall carbs.