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The quality on the cmi headers for the Illmors Suck to.
32b skater with illmors first one. Had blown motor when buddy bought it(because of leaky collector).
Now has one fresh Proline built motor trashed because of leaking header. He is planning to have new collectors built for all 4 of them. I say the way the exhaust bolts up to the collector on his boat is stressing it some to. It needs more support in that area on his exhaust.
Considering he loves speed and rough water.

I would test them every year illmors and others.

EJ.

Don't say I didn't tell people so a long time ago. ;)

Also, anyone who buys the whole Mercury not standing by their warranty because it's not their product and CMI saying Merc called for lower quality build it just fooling themselves. Come on folks, that's not how business works. I'm just tired or reading about all these issues. A stainless tubular header system by nature is prone to having leaks over time. It's physics. Some don't like to hear that but it's the way I see it from seeing and experiencing it over the years. Sorry in advance for offending anyone. :)

Quote:

Originally Posted by IlmorDonzi (Post 3285275)

Damn, you're pretty good at TIG welding. I don't know how much room you have to get to the inside with only 4 tubes, I have 5 tubes to deal with, but I don't have a torch small enough to get in there. Where did you get this very small torch you have? Is it a Miller?

I will pm u the torch # its a weld craft Very small.

Quote:

Originally Posted by Tom A. (Post 3285186)

I have the same volume and pressure coming out the exhaust as I did before the drains were installed and have had NO temperature increase in the exhaust or pipes. I pull the boat after each run or at max. after a weekend and the motors get a thorough fresh water flush.
The picture below shows no significant water coming out the tubes, plenty of water out the tailpipes, and no steam.
The idea of leaving water sitting in the pipes to me makes no sense if you can get it out. Besides the corrosion factor, let's say you do have a weld failure or crack, if there is no water sitting in the tubes, there is no water to drain back into the cylinders.
Most damage occurs from the motors sitting for awhile, the water slowly seeping into a port. Go to start it up and Boom!

The only drawback I have found is you do get little stains from the water dribbling down the transom. Nothing a little Spray-Nine can't fix.:drink:

That is what I am planning to do to my boat as well. Do you have any pics of the back of the engines where the lines attach to the headers? They make orfice fittings that have small holes drilled in them to limit water flow--then you can use whatever size line and thru-hull you want. The total volume of water coming out is small enough to not effect the regular header water flow much. I agree with you that if the water drains out each time the motor is stopped, the water won't have much time to leak into the engine so damage is greatly reduced.

Quote:

Originally Posted by suntimes (Post 3285433)

I agree with you that if the water drains out each time the motor is stopped, the water won't have much time to leak into the engine so damage is greatly reduced.

That's the best thing anyone can do with any kind of header system.

It's not a fix for the problem of a cracked/leaky header but it can limit the damage done by having the water sit inside the pipe/engine. Having a drain tube with cold water spraying on a hot exhaust valve will not save it.

Headers should still be checked on a regular basis. Once headers are 2-3 years old (maybe longer in fresh water) I recommend checking them every winter as a precautionary measure. Also, use some heat when checking the welds... I have seen headers hold pressure perfectly until you put a little heat in it and they begin to seep water. :kiss:

Quote:

Originally Posted by 14 apache (Post 3285381)

I will pm u the torch # its a weld craft Very small.

We weld everyday on thin stainless steel and use the smallest Weld Craft torch they have and still don't have the room on 5 tubes to weld in the middle of the star. 4 tubes MUST have more room. Thanks for the info.

Quote:

Originally Posted by pm203 (Post 3284852)

Dean,

Do not let the header issue deter you from buying a boat. There are lots of these headers with lots of hours that have been fine. I know its a problem for alot of people, but don't let headers dictate what kind of boat you buy.

pm203,
I hear ya, but the cabin was way too small for us also. Plus, I'm seriously thinking about re powering our Nordic with a HP500's that will be tweaked up a little bit and I'll will be running new KE's headers, and I know that they will last forever, and out perform the CMI's. The last set I had lasted for 7+ years running in saltwater.
Happy New Year everyone.
Dean

Hey Guys,

I had all kinds of header problems on my 525 boat. Moved up to 600 SCI's different boat. Headers look the same but no problems so far.

Are 600 headers made the same as the 525's?

Thanks, Mark

Quote:

Originally Posted by MarkDonzi (Post 3286265)

Yes