Exhaust Riser?

[cptbill]

I think that if you've already got them off why not just replace the risers and manifolds

 

[Jack2048]

Here is the manifold before and after. Took about two hours to do.

 

[Jack2048]

I think that if you've already got them off why not just replace the risers and manifolds

$750 is why.

 

[Jack2048]

its never a good thing to run without the water going through.

It was only for about one minute. I had removed the fresh water pump, recirculating pump, alt, power steering.
The engine hadn't been run in five years, and it needed both pumps replaced. One of the bolts holding the recirculating pump in place had broken, and I had my mech use his oxy torch to remove it, as my propane wasn't hot enough.

I wanted to start it up and see that it was going to run before I started dumping $$ into it.

the other thing to check is the T stat , over time they get a build up and close up .

That's a good point, I replaced it years ago, but haven't looked at it in a while.

 

[Dillusion808]

Well $750 or it can cost you a lot more down the road.

Monitor the manifolds they rust and get pin holes. Next thing you know you have water in your cylinders.

I tried to stretch mine this year and ran into that issue.

 

[Lou C]

You can test manifolds by filling the water passages with Acetone and watching for leaks at the exhaust ports. Careful though because it’s quite flammable. It has lower surface tension than water so that’s why it may show leaks where water won’t. Best done with the elbow removed.

 

[Scott06]

Well $750 or it can cost you a lot more down the road.

Monitor the manifolds they rust and get pin holes. Next thing you know you have water in your cylinders.

I tried to stretch mine this year and ran into that issue.

Most of the issue is the sealing surface - they can be filled with acetone and leak tested while off. Acetone will wick into pin holes and cracks and show defects that may not show on pressure test or water filled test

 

[Dillusion808]

Most of the issue is the sealing surface - they can be filled with acetone and leak tested while off. Acetone will wick into pin holes and cracks and show defects that may not show on pressure test or water filled test

Mine wasn't leaking at the gasket and the passages looked very similar to the OPs. $750 is nothing in the boating world and better than having a locked up engine.

 

[Scott06]

Mine wasn't leaking at the gasket and the passages looked very similar to the OPs. $750 is nothing in the boating world and better than having a locked up engine.

yes do what you want with your boat and your money.

to the OP if the sealing surface is good and they pass an acetone test you will not have an issue. In salt plan on replacing every 5-7 years. Inspect every year or two.

 

[Lou C]

In the fall I'm going to replace my elbows because by then they will have been used in salt for 5 seasons. The manifolds I will inspect the sealing surfaces and acetone test. Then evaluate. So far no signs of leaks either outside or in cyls. I have a local dealer where I can buy Barr Marine aftermarket exhaust so I don't have to pay for shipping ($$$ with exhaust because each side is a bit over 40 lbs). Also when I've replaced manifolds etc I take em to the scrap yard, you'll get about $10 for about 80 lbs of cast iron scrap.
Just did a compression test a few weeks back so I'd have noticed if there was water getting in a cyl.
BTW, I think it is a good idea to do both an oil analysis and compression test at the end of each season. That way you know what's happening with the engine and if there are issues you have the off season to rectify it, and not lose time during the season.

 

[cptbill]

Acetone is a good way to test although sometimes small defects become more prevalent with heat

 

[dingbat]

Acetone is a good way to test although sometimes small defects become more prevalent with heat

Magnaflux is a much better process