Offshoreonly.com - Exhaust Headers / 525 Mercury Racing Engines

Offshoreonly.com (https://www.offshoreonly.com/forums/)

- General Q & A (https://www.offshoreonly.com/forums/general-q-20/)

- - Exhaust Headers / 525 Mercury Racing Engines (https://www.offshoreonly.com/forums/general-q/241634-exhaust-headers-525-mercury-racing-engines.html)

Quote:

Originally Posted by Redmen666 (Post 3282008)

What a **** company. I would not exist if i treated my clients in this manner. I will never buy another product from CMI.

Their original 525 headers sucked, they didn't care and marketed them anyway. This can't be a surprise considering their history.

Isn't all this telling us that there's an opportunity here for someone to capitalize on this and create a replacement header that has the same flow characteristics yet is designed such that it doesn't crack? Honestly - this is not rocket science. What's missing is that no one has bothered to address the vibration induced stresses. Once that's quantified, a material can be selected with the right properties for the production processes. IMHO, it lookes like the industry is hung up on stainless steel. Stainless might be great from a corrosion perspective, but some alloys are difficult to prevent work embrittlement - even through heat treating. Welding of certain stainless alloys can be almost futile.

And will all due respect, I'm just amazed that you guys put up with this. My perception is that many of you are successful business people and the sport boat community seems to be very tight knit. Those two things should be combination enough to make any marine OEM's sit up and take notice. Does Merc Racing really feel their too big to fail??

Tom

I just purchased and installed a replacement for the CMI from Stellings. Call and talk to Randy. I have a 525 efi in my Talon.

Here's how you pressure test them. I might do mine every spring.
http://i763.photobucket.com/albums/x...s241Medium.jpg

Quote:

Originally Posted by thirdchildhood (Post 3282688)

Here's how you pressure test them. I might do mine every spring.
http://i763.photobucket.com/albums/x...s241Medium.jpg

Thirdchildhood; Although you may feel this is a good way to test, I would highly suggest sending them back to the factory as they have the correct equipment and process to test them to OEM specification. Properly cleaning and amount of pressure will change the results as well as the position they sit in the water will change the results!! They charge $150 a header plus shipping to properly inspect them, sounds like a GREAT value to me!

Quote:

Originally Posted by Smitty1035 (Post 3282016)

I actually just went through the problem with the CMI headers on my 2004 525's. Second time out for the season I went to get on plane and lost the port engine. The first trip out the week prior to that the boat ran great and the wife even commented that if we didnt have another ride all season it was worth it. Well...she didn't get another ride and took the entire summer to get her back together.

I broke a valve in the port motor and it made a mess of the piston and cylinder when it happened. Pulled both engines and found corrosion on all four heads and 3/4 of the exhaust valves. The apparent cause was that the headers were leaking and splashing the hot exhaust valves.

When I called CMI about getting them tested they said that they really dont even look at them if they are older than 5 years. I have done a lot of research on this and found that my best bet would be to replace them completely and not risk fixing them only to have them leak again and do further damage. I considered several options such as re-drilling the heads to fit standard headers, trying the new Stainless Marine Headers for the 525 and the gen-x sets from CMI. All of these were valid options but I ultimately decided to stick with what came on the boat and replaced them with the OEM CMI's.

We got everything back together by the end of the summer and was able to get a couple runs before putting her up for the winter. I added water pressure gauges to monitor was pressure and will continue to be diligent with flushing after every use.

I have a buddy that has the same engines, same year, 100 hours more and used them in Salt and Fresh water in a 38 Fountain Lightning. After the ordeal that I went through this past summer he had his engines pulled and headers and heads checked for damage. He only had one header that was leaking slightly and absolutely no corrosion or water damage. He is having the one header fixed and everything back together in a fraction of the time and cost. He has a staggered set up in his and I am running silent choice in a side by side set up in a 35 Sonic. Not sure why there is such a difference in the outcome of both of these.

Hopefully some of this info will help point you in the right direction.

Smitty; A proper flushing is a good start to the life of your exhaust, CMI has put together some videos on the difference of water pressure and water FLOW, Flow is the key, pressure doesn't really tell you what is happening when a pump is on its way out or if a heat exchanger is getting plugged up.
Here are the links;
http://www.youtube.com/watch?v=HWGcvwHZSE8
http://www.youtube.com/watch?v=vXB5RRwC_l8
Check them both out.

We went and looked at a 07 38 Donzi zr last Thursday, (the 23rd, my b-day) and the boat is a dealer demo, with 22 hours on it, and the bottom line for us was the cabin is a little too small for our family, and with this header issue still being a problem, I couldn't really buy the boat and not worry about the exhaust issue. I mean in my eyes, it defeats the purpose of buying a new boat with warranties.....
Dean

Stainless Marine Generation 3 exhaust is what lots of people are going to. Im considering it too. Not as much bling, but fully functional and worry free. HP loss doesnt seem to be an issue either. Have seen some powdercoated to match engine color and they dont look too bad! I will sacrafice some bling for the life of my engine.

Quote:

Originally Posted by bbcmi (Post 3284652)

Would you please elaborate on that? What does your testing method do that mine doesn't? BTW, my headers are clean as a whistle inside. They don't need to be polished either.