Do you drain your headers?

[BeerMaker]

Last year I bought new CMI headers for the Merc 525 in the boat. I asked the guys at Teague if I should do anything to help keep them in good shape. He told me that if I wanted, I could drain the water out of them at the end of every trip. He said I didnt have to if I was just running in fresh water but that it wouldnt hurt. So for the last year I have been draining the headers after every trip. Well the last 2 trips in a row I forgot to. Probably distracted from wiping the damn thing down in 110 degree heat.

Anyway, what do the "experts" on here say? Drain them religiously or is it a waste of time?

 

[Singleton]

Drain end of year or if you have months between trips. If boating monthly no need IMO

 

[Abc123]

With stainless double-walled headers, you shouldn't really ever need to drain them. Steel outer wall tube headers like made by Lightning are a different story.

This is what happens if you don't drain the pet cocks regularly.

 

[ka0tyk]

even my EMI/RM manifolds were filled with DISGUSTING black goo water when I started to tear into my motor. I ended up having to swoosh around a little gasoline in them to clean them out. I'll be removing the AN hoses from now on after every trip.

 

[LargeOrangeFont]

Are marine headers typically coated with anything on the inside to protect them or are they raw?

 

[port austin pirate]

Are marine headers typically coated with anything on the inside to protect them or are they raw?

I drain mine after each use, 525 efi easy to do and cheap insurance, Only exception is if left in the water for a few days. Cant hurt and can help why not.

 

[Yellowboat]

I would drain them.

 

[Luvnlife]

I only drain mine before winter so once a year

 

[Boat Potato]

Are marine headers typically coated with anything on the inside to protect them or are they raw?

The freshwater Lightning headers have a jet hot looking coating on the inside but it eventually bubbles and peels off. I drain my lightnings everytime when I remember.

 

[500bbc]

With stainless double-walled headers, you shouldn't really ever need to drain them. Steel outer wall tube headers like made by Lightning are a different story.

This is what happens if you don't drain the pet cocks regularly.

View attachment 437442

View attachment 437443

That happens even if you do, I blow mine out now.

 

[BDMar]

No need to drain CMI's after every trip. (fresh water)

 

[Shortdeck]

Maybe Im crazy, but I drain the whole motor after every trip.

 

[575cat]

Ck out OSO , tube headers are a nightmare 525s ,600s , 700s are known to crack .

 

[Drew01]

My buddy just spent 12K rebuilding his 525 because the CMI's failed and were pumping water back into the motor. So I would drain them if sitting for more than 2 months.

 

[BUSTI]

Drain the motor and headers if you are winterizing a boat. If you are using the boat a lot like once a month even in the winter no need to.

 

[BeerMaker]

Ck out OSO , tube headers are a nightmare 525s ,600s , 700s are known to crack .

Yea I read all the horror stories last year when I was researching buying the boat. That's what lef me to have Teague pressure check them the day I took delivery. They tried to repair a small crack just to find another that they couldn't reach. We talked about buying a customer take off set but I wasnt comfortable. Just popped for a new set.

 

[Parkrbound]

I drain everything each trip. I drain sea strainers, drain block, drain and blow out turbo housings, exhaust manifolds and hoses connecting to and from.

 

[C-2]

I took my Lightning's in saltwater ONCE and ended up with a leak and a chocolate shake. And that was with draining after every use, including freshwater.

What's the big deal, just drain them :thumbup:

 

[ToMorrow44]

No need to drain CMI's after every trip. (fresh water)

Same. Never even thought about it. I've had the same set of CMIs for 14 years with zero issues and never drained them. Handful of saltwater trips too. The original CMIs for the 525s were built to a Mercury spec and were inferior, but if you have new CMIs I wouldn't worry anything about it.

 

[H20 Toie]

if you run in the salt then you must flush the motors , no need to drain the headers
if in fresh water then no need to drain the headers
only time you need to drain them is if its going to get real cold ( you don't want the water to freeze )

the old cmi headers for 525's had problems from heating up and cooling off and would crack. draining them isn't going to change that.
now it remains to be seen if the new gen x headers are better
if you want to be sure put on a set of stainless marine exhaust and never think about it again ( but they don't look as cool)
also Hardin marine makes a beautiful heavy duty set of headers for the 525s that should last a long time.

 

[BeerMaker]

if you run in the salt then you must flush the motors , no need to drain the headers
if in fresh water then no need to drain the headers
only time you need to drain them is if its going to get real cold ( you don't want the water to freeze )

the old cmi headers for 525's had problems from heating up and cooling off and would crack. draining them isn't going to change that.
now it remains to be seen if the new gen x headers are better
if you want to be sure put on a set of stainless marine exhaust and never think about it again ( but they don't look as cool)
also Hardin marine makes a beautiful heavy duty set of headers for the 525s that should last a long time.

I wanted those Hardin marine units real bad but last year when I found out I needed replacements, they told me they were back ordered several months. Teague was able to get me new gen x CMI headers in 2 weeks. Heard great things about the Hardin units.

 

[BeerMaker]

Thanks for the replies everyone. So sounds like I will keep doing it when I remember. But I will definitely drain at the end of the season.

I have a follow up question now. As I mentioned I have a brand new set of CMI gen x headers that Teague installed this time last year. I have read all the bad stories and I am aware that they all Crack at some point that's why I had the old set pressure tested before I ever ran the boat. I have heard that most people pressure test every off season. Would it be over kill to pressure test a set that is barely a year old? Should I wait till year 2 or 3 or?

 

[BDMar]

Thanks for the replies everyone. So sounds like I will keep doing it when I remember. But I will definitely drain at the end of the season.

I have a follow up question now. As I mentioned I have a brand new set of CMI gen x headers that Teague installed this time last year. I have read all the bad stories and I am aware that they all Crack at some point that's why I had the old set pressure tested before I ever ran the boat. I have heard that most people pressure test every off season. Would it be over kill to pressure test a set that is barely a year old? Should I wait till year 2 or 3 or?

As Dan said, they cracked from heating and cooling. The new CMI's are supposed to be much better. If you haven't overheated them from lack of water, no need to pressure test them this soon. I would do it every other year until year 5, then every spring.

 

[CoolCruzin]

Never thought the cmi headers and others was that mutch of a
up keep .. Just learned something

 

[Rsqfxr]

Never thought the cmi headers and others was that mutch of a
up keep .. Just learned something

Yes definitely something to keep in mind, my boat is stored locally so i try and pick it up once a month or so to let it run on the hose

 

[Sonic45SS]

Same. Never even thought about it. I've had the same set of CMIs for 14 years with zero issues and never drained them. Handful of saltwater trips too. The original CMIs for the 525s were built to a Mercury spec and were inferior, but if you have new CMIs I wouldn't worry anything about it.

I have 3 sets of the polished stainless CMI's in the Sonic, never have drained them ever. Even at winterization, they just get flushed with antifreeze. I flush the boat after each use. Never had a problem with them.

As others have said the original CMI's were an inferior design pressed upon CMI by Merc in what I would guess was an effort to keep costs down. The replacement CMI units are a newer and better design. The original generation on the 525's etc did have a lot of issues. Merc also had a different exhaust bolt pattern drilled in aluminum heads also. The heads are supposed to be edelbrock units built to Merc specs.

 

[BeerMaker]

As Dan said, they cracked from heating and cooling. The new CMI's are supposed to be much better. If you haven't overheated them from lack of water, no need to pressure test them this soon. I would do it every other year until year 5, then every spring.

Makes sense. Thanks!

 

[rivergames]

I put magnesium blocks in my sea strainers to eat the water. So far it has worked, but I need quite a bit more time to fully know

 

[28Eliminator]

I put magnesium blocks in my sea strainers to eat the water. So far it has worked, but I need quite a bit more time to fully know

Can you elaborate on your reasoning? I get the theory behind the sacrificial anodes on the outside of the boat, but I've never heard of this.

 

[82daytona]

How can you tell if you have the new or old CMI's?

 

[575cat]

Go stainless marine but have to get the jig to drill & tap heads , or thunder & lightning alum headers .