C M I 's
 

What is the average lifespan of CMI headers from the mercury racing factory, installed on their 500 & 525 efi's ? Have any of you guys had them start leaking internally on you ? If so ,how many hours did you run them before they leaked ,and did their failure cost you more than a replacement set .......................(ie, valves,heads ,ect. ).I've heard a few different stories ,would like to hear yours:eureka:

Plenty of failures discussed with 525efi headers. The 500efi's have different headers.

Are they just as bad ? or do they have a better track record ,I'm looking at a boat with 500 efi's and 287 hours ,was wondering how much longer I can expect to get out of them ,and will I know when to change them before anything else gets damaged from them leaking ??????????????????????:(

TRICK has an extended warranty plan if you buy from them



Just Kidding.......don't take this advice :)

500EFI headers have not had the failure rate of the 525EFI. They are pretty much a standard CMI E Top. The 525 headers were spec'd out by Merc and they had Cmi build them.

Mine in a 382 with 500EFI's lasted for about 200 hours. Then needed complete engine rebuilds due to leaks into the heads. And that was even with regular fresh-water flushing.

Oh: needed new headers and tail-pipes, too.

The original Silent-Choice lasted even fewer hours.

Salt kills!

Wow that sucks, Did you keep the boat in year round ? any signs of leakage prior to head job ????????????????????:(

my cig has 300 hrs no problems with the headers yet on my 500 efis hope i didnt just jinks myself

stellings i had zero problems with mine..

As Griff stated, the 500 uses the Elbow Top Header which is a very durable long lasting header. The 525 used a Merc specified and designed header that appears to have higher failure rate than other designs.

Providing the headers were drained and/or flushed if used in salt water, properly winterized in cold climates and had adequate water flow while running, they will last as long as any other exhaust system.

You can pressure test them and if there is an issue, they can usually be repaired.

If we can help, let us know.

Kirk
Ateco Engine and Dyno Shop