Ok, sorry but after holding in my comments for over a week - - - here I go. I lost 2 mtors to leaking headers on my last boat. Rebuilt both and sold the boat. My 700 boat I have now, all 4 headers leaked and 3 of the 4 pipes. Needless to say it cost me alot of cash to replace all of them and now because of the water leaking in the motors I had to have both the upper and lowers done. BTW, mercury does not offer larger pistons for the 700, They want you to buy the entire lower end. Uppers I can understand needed attention at 200+ hours, but lower as well? Thanks CMI...100K spent in headers, pipes, and rebuilds. It makes me sick to read the page in Powerboating in Paradise where CMI has a page where all the major boat manufacures and dealers talking how great a product CMI has. I am here to tell you - 100K out of my poket is far from GREAT. i almost lost my dinner reading that page. Ok, I am done, sorry to vent..

thanks mykalvballer and sorry to hear that. do you run in fresh, salt or brackish water? also are your motors staggered?

This is what I was told as well. What is baffling is the fact that CMI continues to do this as it's their name that seems to get dragged through the mud, not Mercury's.

Maybe Mercury Racing will speak for themselves?
 

It I remember Fred is a member here on OSO. Why doesn't someone here on OSO directly affected send him a PM and ask for Mercury Racings direct response. If not how about someone so affected put up a blog on their website blog page and see what happens??? Maybe even a direct written email to Fred. this is certainly a sad thing and when I read something like the post here from Mikalvballer it sort of makes my stomach sink. Very, Very, Very bad!

Alright guys here is the deal. I am looking at a 2005 boat with a single 525 efi. It has no choice exhaust but does have bolt on mufflers. It has only 100 fresh water hours. I will only run in fresh water. So all things considered in my previous posts, my questions are:

Should I be concerned?

If yes then do I put Hardin hurricanes or gen-x on?

I don't want to drill/tap the heads or stainless would be considered.

Like I said, I have been told the header issue does not pertain to single engine fresh water boats......

Buy it.

Done! Now what?

Does anyone actually have any proof of this? When I called CMI, they responded that the Merc specs were actually more stringent than their own. I don’t buy into the salt water issue either. I had Gil stainless risers that were used for twenty years in salt and still looked brand new. So do my CMI’s inside. Not one speck of corrosion. I do believe that stress induced by improper support and/or overheating is an issue.

You could pressure test them. Mine have not been a problem. 2007 engine.

I would pressure test them. You can even send them to CMI for inspection for not much money. The only thing is the bolt-on mufflers. Who knows how much back pressure they create. Reversion and failed headers are 2 different issues.