Offshoreonly.com

Offshoreonly.com (https://www.offshoreonly.com/forums/)
-   General Boating Discussion (https://www.offshoreonly.com/forums/general-boating-discussion-51/)
-   -   CMI HEADERS 700 BOAT LEAKING NEED lOPTIONS (https://www.offshoreonly.com/forums/general-boating-discussion/305543-cmi-headers-700-boat-leaking-need-loptions.html)

gnorthga 11-19-2013 08:09 PM

CMI HEADERS 700 BOAT LEAKING NEED lOPTIONS
 
07 model 700 motors headers are leaking OMG new ones are out of sight

Had them fixed once by CMI
back motor rite side leaking again

What would you do or have you done about this problem if anyone can give some advice

Perfect Storm 11-19-2013 09:40 PM

:daz: In my opinion, you should replace the CMI's ASAP. It's better to replace them now BEFORE you smoke one or both of your motors, because then you'll be spending a lot more $$$ on motor(s) and you'll STILL need to buy new headers! If you keep repairing them you're just chasing your tail and risking your engines in the process. I know it sucks (!) because I had to deal with the same issue in 2011 with the CMI's on my '03 525EFI's with only 135 fresh water hours on them... I just bit the bullet and replaced them. It made me extremely upset that I had to spend that kind of money on new headers that I NEVER thought I'd have to replace (AND SHOULDN'T HAVE HAD TO) but smoking one or both of my motors (because of leaky headers) would have been FAR worse!

Kat Krazy 11-19-2013 10:17 PM

This place saved my big tube headers. Superior Welding Punta Gorda FL 941 639 2966

Or buy new AFTER MARKET CMI's. Don't buy the Mercury. You will see that After-markets are heavier.
Offshore Performance Specialties Fort Myers FL (239) 489-0884 call Donney he has very good prices.

Expensive Date 11-19-2013 10:41 PM

http://www.cpperformance.com/p-16690...dard-exit.aspx

While I do not have 700,s or CMI's on my boat if I did this is what I would do.

Gladhe8er 11-19-2013 10:48 PM

Perfect Storm is 100% correct. I have lost a couple of seasons because of those stupid headers. I replaced them last year with stainless marine headers.

Indy 11-20-2013 05:56 AM

How that company hasn't had a class action lawsuit is beyond me. Without question one of the worst high performance boating products to ever be marketed. I'd replace them with anything other than CMI.

bjablonski 11-20-2013 06:11 AM


Originally Posted by gnorthga (Post 4029775)
07 model 700 motors headers are leaking OMG new ones are out of sight

Had them fixed once by CMI
back motor rite side leaking again

What would you do or have you done about this problem if anyone can give some advice

Just curious, did you pressure test the headers and found the leak? or was it something else...

I have the same motors, seeing things like this makes me nervous

gnorthga 11-20-2013 06:21 AM

Perfect Storm

Did you go back with CMI mercury headers or did you get non mercury CMI headers.

A good friend of mine said CMI headers are fine just dont get the ones mercury has CMI build to there specs.

If you put mercury CMI on did you have any trouble after you installed the mercury CMI new headers?

gnorthga 11-20-2013 06:39 AM


Originally Posted by Kat Krazy (Post 4029842)
This place saved my big tube headers. Superior Welding Punta Gorda FL 941 639 2966

Or buy new AFTER MARKET CMI's. Don't buy the Mercury. You will see that After-markets are heavier.
Offshore Performance Specialties Fort Myers FL (239) 489-0884 call Donney he has very good prices.

I talked to Donny yesterday, great guy to talk to about boat parts his dad Don Carter was a big time boat racer back in the day.

Donny said mercury improved there headers in 09 re-did the collector area and its been 4 years and he has not saw any go bad but OMG he wants $5500 a set x 2 $11000.00 I am now saying I cant afford them I just think thats a little high for 2 sets

gnorthga 11-20-2013 06:51 AM


Originally Posted by bjablonski (Post 4029885)
Just curious, did you pressure test the headers and found the leak? or was it something else...

I have the same motors, seeing things like this makes me nervous

Listen i have owned this boat going on 4 years and i know how to keep it running for a complete season

during off season
1. pull out all fuel injectors get flowed
2. pressure or water test headers
3. remove all old fuel
3. replace water pumps and change oil in fuel pump assembly replace mechanical fuel pumps if gas is present
4. leak motors down
5. if seaweed is present in intercoolers remove and send to radiator shop or re-install (install better sea strainer just for intercoolers to end this process.
5. new mercury fuel filters and water separators.

This is annual maintenance every year to keep from breaking down in the middle of a season when I do this ever year we are able to make it to 6 or more poker runs a year and play on our lake 95% time trouble free


All times are GMT -5. The time now is 07:48 PM.


Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.