SeaDated

For what it is worth I had my headers crack and leak at 260 hours of mainly fresh water use. I was seeing water drops on the oil fill cap. I read tons on here about them getting corroded and leaking and cracks too. My cracks were at the top where the four tubes enter the collector area. I had them repaired locally. The shop removed all of the original welds material and re-welded with 321 stainless rods which have higher nickel content then the 316 which CMI uses. The increased nickel allows for better expansion and contraction.....time will tell. I used a bore scope to inspect the water galley area and found NO CORROISION at all....again mainly fresh water but never drained. Also like many on this site only my forward engine pipes cracked possibly suggesting vibration and fatigue. My rear engine is fine.

I made a very simple, fast, and inexpensive pressure test kit so I can check the pipes in the future. It takes about 10 minutes per engine. Maybe a test kit would set your mind at ease and save money too. I agree with the folks on here...headers will fail it's just a matter of when.

bada-bing

hey Frank ,it's Joe Amoroso.....I've been reading the posts on here,and man i am having issues with CMI.I'm at the point of getting in touch with boat publications,and maybe even litigating.I had a new starboard side starboard header,and 2 neew exhausts put on a month and a half ago.I noticed an exterior leak 2 weaks ago.Upon further evaluation,noticed that where the exterior leak was,(near i believe the coupler?)there was a missing weld.My mechanic informed me,that the new setup leaked into the 6&8 cylinder.Now i have to have this replaced,as well checking the other side (port engine)the port side header is leaking on this side as well.Last June sent all 4 exhausts back to Cmi to have them pressure tested and rewelded.This was because of damage that occured to my # 6-8 valve on my port engine.All Cmi does is give you run around bull****!!!

Shanghied Again

This problem seems to be happening on CMI to Mercury set ups 525s and 700s.
Nor-Tech started putting in By-Pass drains in the CMIs and it seems to help, we have installed them in a few 525s and now we are doing it in a 700 that just had a CMI failure, had the headers rewelded.

racer-x6

I run antifreeze in mine,

AIR TIME

I feel for you that stinks man, I have had my stainless marine for 14 years gen 2 dry they don't look as nice as the stellings or cmi but made as much hp. now with the gen 3 with 4 1/2'' tails your exhaust flows better, try looking them up my bud had to have his Etop cmi head fixed after 3 or 4 seasons. so look at SM.

thedonz

I took my Stellings off because of continuos leaks, replaced with SM Gen III and haven't had any more problems and make more power.

Dean Ferry

eikerts are the way to go, IMO.
Dean

Panther

Nice!

I had the Gen III's in my hands and was ready to make more power over my E-tops, I couldn't wait, then found out the hard way that my centerlines are too tight.. The Gen III's require at least a 33-34" crankshaft centerline, I was at 32". They even sent me a pair of machined manifolds, still no luck... I can honestly say they are a GREAT piece and the ports are huge, no wonder they do so well on blower motors.

I wound up going with the Gen II system and we made the tails 95% dry and did a 4" to 4 1/2" step up in pipe size. I did not notice any power difference between my etops and the SM II"s... The SM III"s would have made more power.

I had the Gen II's on my last boat and they were over 10 years old and performed wonderfully. I have no reason to expect any less out of my new system!

Wazzup Racing

One thing to keep in mind. When the salt water leaks into the exaust cavity, it lays on the bottom of the header gasket, and begins to eat it's way through the aluminum Cylinder head. Which in that exaust area is less than a 16th of an inch thick. I have a pile of junk 525 heads. Pay close attention, to your headers, those heads are not cheap, as they are Mercury only parts. Smitty

Panther

What a mess.....

But, Trione should be able to fix those heads, no?