525 CMI Header Issues?
 

What years were these problems? What was done to correct the problem?

all years.......don't use is the only way to avoid issues!!! :) They all leak eventually, very quickly in salt water!!!

Pull them and send them to CMI at about 200 hours. The refirb cost is better than the alternitive. They cost $150 a pair to refirb at CMI plus shipping.

I have about 140 hours on mine...no problems, knock on wood. My brother has had all sorts of problems with the headers leaking, but has at least twice teh amount of hours.

One way to help assure no problems is to install drains. These will drain header to an overboard dump so no water remains in header while not being used.

Yes water will flow while motor is running, but negligible on cooling ability.

This WILL make your headers last MUCH longer. Also, do not use 90 degree fitting as shown or aluminum. I am pretty sure the 525's have the ends (towards stern) on the water feed tube already threaded. You'll need an adapter to (std size) to go from what is already tapped into header drain to bring it down to #8 or #10 AN.

Eddie Marine has SS overboard dumps. Easy to install, and works!

Great Idea. Someone should make a kit for this modification.

Is it ok to leave the pink antifreeze in them after winterizing? Or drain that out too.

After all I've read on this issue...drain em!

And yes, the 525's do have the threads on both ends. Great post Bill.

There is a factory mod to remove the bypass hoses and drill the top fitting on the Stb. side. More water goes though the headers. I think it keeps the headers cooler making the the heating and cooling cycles not as extreme. The letter I have says #OM956327 and up. Doug

Do you have any more info on this? Where can I find out how to do this? Thanks.

That's part of the closed cooling system.

Pat, I mean leaving the antifreeze that I ran through the seawater side of the system to winterize it. Filling the headers and heat exchanger etc. I didn't drain the closed side as it has antifreeze in it. I would think the antifreeze would help protect the headers.

Actually, I believe it is a fitting that screws in - not 100% sure, but whatever - remove it or drill it! The restriction might be on both sides.
Much better flow and will help to last longer.
Leave the AF in or drain. No big difference either way. As long as the AF has traveled through the header; then you'll be fine. The AF displaced any water and left a film to help protect against corrosion.

Honestly these people from Florida just don't have a clue:lolhit: Steve

Here is the info I recieved. Both bypass hoses are removed and pluged. Stb. side is drilled out to .406 or 13/32 drill bit. Port side was already .406 like the drawing shows. Check your model. :) Doug

Bypass hose? Are you talking about the hose from the Water manifold that runs up to the header collector at the back of the water manifold?

It runs from the back of the water manifold under the header to the bottom of the tailpipe. In the diagram they are circled on the bottom of the tailpipe. After this is done all the water goes through the header then the half moon top hose out the tail pipe. The back of the water manifold and bottom of the tailpipe are plugged after the hoses are removed. The top fitting is drilled out to 13/32 on the stb. side. The only reason I found out about this is I bought a new set of headers. I went to put it together and the fittings on the water manifold were different which prompted some phone calls. The hoses that are removed are aprox 10" long and 1" I.D. I would think this would apply to any engine with sweepers, but please check. Doug

I bought the plugs at Home Depot but they didn't have a 13/32 drill bit but Lowe's did. I just put plugs in the aft bottom of the water manifold for now, I'll get the bushing for the blue wing plugs in the spring. P.S. I pulled the plugs and let the anti-freeze drain. I sleep better that way, just paranoid about any fluid sitting in the headers for any lenght of time even with new headers. The engine has dyno time only. Doug

thanks. Thats the hose I thiught. I will call CMI and make sure. I see the picture, Who do you work for?

Excuse my not knowing. Why drill out the top fitting to 13/32?

Dennis, Maybe a better question is why the port side is already 13/32 or .406 and the Stb. side is smaller in the first place? Buy drilling the Stb. 13/32 or .406 it makes the same as the port side. When I did mine I checked it and the port side was already .406 and had to drill the Stb. to make it the same. I think I'm confusing myself now. :) Doug

LOL. I think I am understanding now. Do you have any photos of your finished product? Thanks for shareing your knowledge it is most welcome.

I don't have any pic's at the moment but I have to take the boat outside to move stuff around before winter and I'll try to get some then. I have to credit Don Carter from Offshore Performance Specialites for helping me with this. The parts pic is also his work, he gave me permission to post it. I wouldn't have known about it all if I wasn't scratching my head when I went to plumb the new headers. Doug