Ok guys here goes

I need your help to decide what to do.
I have a 525 take out with stock headers as spec by Merc.
They seem to have a product that might leak into the engine and then bad stuff happens> I do not know for sure they have a problem but there is a whole lot of whispering going on.
The same company that made the headers for merc is making a replacement model I understand.

So
1. Do I change the headers and not worry about water entering the exhaust. Reversion
2. Run them since I tested them (no Leak yet 35 hours on the engine) but I had a stuck exhaust valve #8 cylinder to fix on the first start up.

i am not sure what I would do in your case.

Yes people are having problems. On the other hand there are a LOT of those headers out there and you ONLY hear about the nightmares.

If you have the money - change them.

Not sure about the whispering, seems more like shouting to me. Tons of threads on OSO about this issue. If you have the money I'd change them out. However I'd not be to thrilled to replace them with a model from the company who's headers failed so many.

I wouldn't change them, but I would pull them off and pressure test them. CMI has been good at repairing them.

I had an issue with my cmi headers leaking on my Cigarette.
I blew one engine because of it so I bought 2 new long blocks from Mercury & had the headers checked & repaired.
They told me they would be good to go. Well wrong.
About 20 hrs. later we got water in both engines & did more damage to the new engines.
I then had to have the new engines rebuilt & bought two new sets of CMI headers. If I would have bought the new headers in the beginning I would have saved a TON of money & aggravation. Plus I missed a few good poker runs because of it. If I bought another boat with CMI headers the 1st thing would be to replace the headers.
4 engines later I learned my lesson the hard way!

I don't understand with all the problems with CMI headers why would anyone want to keep buying them? After all the failures that are talked about and lost engines I will never use them on mine. I'd rather be down 10-15 HP with another brand than go through the problems others have experienced.

Yeah, but how long with they last?

I have heard it it both ways. Some have said just buy new ones, otherwise you are going to be chasing holes. Then I have heard others say that why would you spend all that $$ when you are getting the same thing that you already have. If I had the $$ (to just throw away) I would buy new ones. The next best thing in my opinion is to send them to CMI for them to go through them.

When 525 efi's came 1st came out the aluminum heads had a different bolt pattern than cast iron heads. CMI were hooked up with Mercury Marine to make the headers.
After a few years I think Stelling started to make that header also.

Lucky Strike,

Why did you stick with CMI and not go with Stelling or some other brand?

Yes Stelling now makes 525 headers. We have repaired numerous sets of these headers. Since your motors has such low hours take the headers and have them pressure tested. If you dont want CMI to fix and test them we'd be happy to do so for you.

Dan