Header drain???

Old 05-04-2008, 07:47 AM
Registered User
Thread Starter
Join Date: Jun 2006
Location: Saucier/Gulfport, MS
Posts: 497
Likes: 0
Received 0 Likes on 0 Posts
Default Header drain???

As I'm learning more & more about my "new to me" Prowler, & the in's & out's with it...It brings me to a question I have about the headers on the 525SC (I'm assuming they are CMI's)...
I've read & heard about the "issues" with the late model header systems on the 525EFI, & I do realize they are different headers, & it seems that there is advice about draing the headers after each use. So, I started looking at my headers. I do in-fact, have a tube running along the bottom & there is a plug at the end of it. Is this where folks are installing petcocks for draining?
Second part of the question....
I've also heard of folks installing dump fittings in the transom & connecting them to the headers for this purpose. With that set-up, do the headers drain constantly, or is there a petcock that controls this?
Thanks for the input...Again, just trying to learn bout my "new to me" boat...
rangerrick63 is offline  
Old 05-04-2008, 01:09 PM
Charter Member # 55
Charter Member
Griff's Avatar
Join Date: Oct 2000
Location: Omaha/LOTO
Posts: 18,807
Received 1,142 Likes on 559 Posts

525SC headers are standard CMI E tops. The don't have the issues of 525EFI headers and half the price. Treat them as any other HP exhaust.
If you're in salt water, flush the engine VERY well. The intake is aluminum and salt will eat away around the water passages. My 525SC was in salt for about 200hrs before I got it and when I pulled it apart at 350hrs, the intake needed to be welded up. It was close to major failure.
Griff is offline  
Old 10-27-2015, 05:35 PM
Join Date: Oct 2015
Posts: 15
Likes: 0
Received 0 Likes on 0 Posts

Any more info on this drain through transom job
29rocket is offline  
Old 10-27-2015, 07:54 PM
el indio's Avatar
Join Date: Feb 2004
Posts: 2,871
Received 7 Likes on 5 Posts

Natural gas petcocks on the water feeder tube is cheap insurance. .if the header leaks it goes in the cylinder. .drained no problem. ..just educated opinion on the matter. .it's not If they are going to fail..just when...
el indio is offline  
Old 10-27-2015, 08:59 PM
Platinum Member
Platinum Member
Tom A.'s Avatar
Join Date: Nov 2002
Location: New Jersey
Posts: 4,280
Received 63 Likes on 21 Posts

I have them on my boat and they have worked flawlessly for many years. When the engines are running there is enough pressure that the water doesn't go down the drains but as soon as you shut down, it just trickles all the trapped water right out so there is a huge reduction in the chance of reversion or leaks into the motors.

You can see them just above the waterline by the tabs.
Attached Thumbnails Header drain???-415.jpg   Header drain???-tampa-spring-2013.jpg  
Tom A. is offline  
Old 10-28-2015, 08:54 AM
Gold Member
Gold Member
Dave M's Avatar
Join Date: Oct 2000
Location: Hollywood, MD, USA
Posts: 5,598
Received 75 Likes on 49 Posts

My CMI's (525efi) had the blue thumb screws at the end of the rails. I just unscrewed and left them out after I flushed. I have Stainless marine now and just disconnect the hoses at the bottom of the manifolds when the boat is not in use.
Dave M is offline  
Old 10-28-2015, 09:57 AM
Platinum Member
Platinum Member
iTrader: (3)
HyFive578's Avatar
Join Date: May 2013
Location: Long Island, NY
Posts: 1,762
Likes: 0
Received 4 Likes on 4 Posts

I have ball valves at the end of the distribution rails of each of my headers. When I'm done flushing and the headers are cool, I open the valves and let all of the water out. CMI recommends against a full time open drain system as the risk is there that it may bleed off cooling water. I'm not disputing Tom A's success with his system; just reiterating what I was told from CMI. I do think though that the lack of bleed on Tom's system is due to the fittings he's used... might be helpful to see a picture of your setup Tom from the inside...

Last edited by HyFive578; 10-28-2015 at 10:00 AM.
HyFive578 is offline  
Old 10-28-2015, 03:15 PM
Platinum Member
Platinum Member
Tom A.'s Avatar
Join Date: Nov 2002
Location: New Jersey
Posts: 4,280
Received 63 Likes on 21 Posts

I found a pic that shows the drain tube set up (ignore the dirty bilge!).
I am not sure of the size fittings as Ron Potter set it all up, but it is reduced to something smaller than the factory outlet.

I was skeptical about it at first but trusting Ron and after seeing it not bleed a drop (even on a hose), I was convinced.
Once the engines are shut off, it takes a a minute or two before anything starts dripping out of them but it definitely works.

Here is a link to an idling video but you can't really see the drains.
Attached Thumbnails Header drain???-sea-strainers.jpg  

Last edited by Tom A.; 10-28-2015 at 03:18 PM.
Tom A. is offline  
Old 10-28-2015, 11:45 PM
Charter Member#568
Charter Member
bck's Avatar
Join Date: Dec 2000
Location: Western N.Y.
Posts: 2,186
Received 14 Likes on 12 Posts

Anyone know of any electrically operated valves? I have drains on mine but it's a pain crawling around the engines to reach them.
Straight bottoms and flat decks
bck is offline  
Old 10-29-2015, 08:43 AM
iTrader: (1)
Join Date: Jun 2009
Location: Chicago
Posts: 7,759
Received 2,681 Likes on 734 Posts

Id rather have all my parts under water then let oxygen at em to start the rust process.
ICDEDPPL is offline  

Quick Reply: Header drain???

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.