Manifold and riser - Needs to be replaced? (pics)

[Mini hog]

In October, when I was doing the winterization of the boat I checked the manifold and riser to see if it needed to be replaced. I need your support since Im new to these inboard engines.

First pic is from the spacer block. Seems to be in good condition and doesn't needs to be replaced.

Second pic is the non-return valve(?) It seems to be broken and I have to replace it?

Third pic is focusing on the bottom of the manifold. It seems to be some rust there. I don't remember seeing this back in October when dismantling the riser. Could it be from 5-6 months of air humidity? To me it seems strange that the manifold is leaking water since the spacer block and riser is in good condition. I didn't have any issues at all with the motor when I took it out of the water in October. If it was from the manifold leaking water there would been a lot of white smoke from the exhaust? Or the engine would stall and die?

 

[alldodge]

In October, when I was doing the winterization of the boat I checked the manifold and riser to see if it needed to be replaced. I need your support since Im new to these inboard engines.

First pic is from the spacer block. Seems to be in good condition and doesn't needs to be replaced.

Second pic is the non-return valve(?) It seems to be broken and I have to replace it?

This is your exhaust flappers and do need to be replaced. You also need to look in the exhaust tube to find the piece that broke off. Pull the drive off and look in the exhaust tune. As with all questions we need to know what your working on.

Third pic is focusing on the bottom of the manifold. It seems to be some rust there. I don't remember seeing this back in October when dismantling the riser. Could it be from 5-6 months of air humidity? To me it seems strange that the manifold is leaking water since the spacer block and riser is in good condition. I didn't have any issues at all with the motor when I took it out of the water in October. If it was from the manifold leaking water there would been a lot of white smoke from the exhaust? Or the engine would stall and die?

You need to either pressure test the exhaust or put some acetone in it and watch for it to leak out. Your gasket areas look clean so I would say its not leaking from the gasket.

 

[Mini hog]

Okay, I will order a pair of exhaust flappers. Its a Mercruiser 350 LX with a Alpha Gen II drive.

I don't have the equipment to pressure test the exhaust. How do I test it with acetone?

 

[alldodge]

Okay, I will order a pair of exhaust flappers. Its a Mercruiser 350 LX with a Alpha Gen II drive.

I don't have the equipment to pressure test the exhaust. How do I test it with acetone?

Remove the manifold, plug the water inlet, then pour acetone in the slots. Rotate the manifold keeping the acetone from pouring out and see if any of it leaks out. If you make a plate and make a gasket you can bolt it on and be able to rotate more.

Now its not that had to pressure test. Put manifold and elbow together, install exhaust rubber boot on the elbow. Cut a round circle out of wood and put it on the other rubber boot end, clamp in place. Put and air source in the water inlet port, can use a bicycle pump if need be but compressor works better. Put manifold in tub of water or spray water on it with soap mix.

 

[Bondo]

Now its not that had to pressure test. Put manifold and elbow together,

Ayuh,.... Leave the elbow off, assemble the manifold, 'n riser blocks, cap 'em with a block of wood, 'n piece of rubber for a gasket,....

Then adapt a shrader valve from a plumbin' store into the water port on the manifold,..... plug any extras it's got,...
Ya oughta be able to hold 'bout 15 psi, nearly forever,...

The risers/ elbows are tough to test, because of the dump ports,... when in Doubt, Toss 'em,....

 

[Mini hog]

hmm... maybe replace everything to be sure that I won't have a failure later this season.