525 EFI Beware?
#11
Registered
Thread Starter
Join Date: Nov 2003
Location: Ottawa Ontario
Posts: 272
Likes: 0
Received 0 Likes
on
0 Posts
#13
Registered
Thread Starter
Join Date: Nov 2003
Location: Ottawa Ontario
Posts: 272
Likes: 0
Received 0 Likes
on
0 Posts
![Default](/forums/images/icons/icon1.gif)
The thing I've noticed aboutt he 525 headers is that they seem to terminate very close to the transom - doesn't leave alot of room to re-route to the existing 496 exhaust holes in the transom, and I wonder if you could ever go with CMI's silent choice system and have any room left at all to reroute...
#14
Registered
![Default](/forums/images/icons/icon1.gif)
The 496's don't have as many problems because of the HP/CI ratio.
496 / 425
502 / 525
The displacement difference is negligible (let's not get into too many bore x stroke and compression details) but the power is 100 hp more.
Ream the piss out of a 525 vs. a 496 and chances are the 525 is going to break first even though you'll have a lot more fun doing it
496 / 425
502 / 525
The displacement difference is negligible (let's not get into too many bore x stroke and compression details) but the power is 100 hp more.
Ream the piss out of a 525 vs. a 496 and chances are the 525 is going to break first even though you'll have a lot more fun doing it
![Big Grin](/forums/images/smilies/biggrin.gif)
#15
Gold Member
![](https://www.offshoreonly.com/forums/images/icons/gold_member_star.gif)
Join Date: Jan 2004
Location: Houston, Texas
Posts: 491
Likes: 0
Received 0 Likes
on
0 Posts
![Default](/forums/images/icons/icon1.gif)
The thing I've noticed aboutt he 525 headers is that they seem to terminate very close to the transom - doesn't leave alot of room to re-route to the existing 496 exhaust holes in the transom, and I wonder if you could ever go with CMI's silent choice system and have any room left at all to reroute...
#16
Registered
Join Date: Jun 2008
Location: Euless, TX
Posts: 63
Likes: 0
Received 0 Likes
on
0 Posts
![Default](/forums/images/icons/icon1.gif)
What is the best way to monitor the header issue....check for milky oil everytime? Are there external hints on the headers themselves that might reveal a problem before it gets to serious?
#17
Offshoreonly Advertiser
![](https://www.offshoreonly.com/forums/images/icons/charter_member_star.gif)
![Default](/forums/images/icons/icon1.gif)
You will start to see whipped cream/moisture in the valve covers first.
Please excuse this shameless commercial plug but I have a fresh - direct from Mercury - full warranty - brand new exhaust - 525 I can sell for $25,000
Please excuse this shameless commercial plug but I have a fresh - direct from Mercury - full warranty - brand new exhaust - 525 I can sell for $25,000
__________________
Marc
www.mercruiserparts.com
www.go-fast.com
www.bammarine.com
www.cyborgtransmissions.com
It's not alive -www.BoatStuffExpress.com - temporarily retired
Marc
www.mercruiserparts.com
www.go-fast.com
www.bammarine.com
www.cyborgtransmissions.com
It's not alive -www.BoatStuffExpress.com - temporarily retired
#19
Registered
![Default](/forums/images/icons/icon1.gif)
I have a some of the creamy stuff in my lines from the valve cover vent on my 502 mpi, but i took it as just condensation. I run the vents up to my eddie marine flame arrestor. Engine has IMCO headers with the feed through from the manifold to the riser. No external hose fittings. Something to be concerned about, or not?
#20
Offshoreonly Advertiser
![](https://www.offshoreonly.com/forums/images/icons/charter_member_star.gif)
![Default](/forums/images/icons/icon1.gif)
Any engine will create water vapor in the crankcase, it is a combustion by product. As the vapor cools the water condenses. So a little bit is normal. Any water that makes it to the combustion chamber from a leak or reversion from the exhaust is also going to wind up in the crankcase (at least a portion of it). I don't get nervous until I really see water in the valve covers.
__________________
Marc
www.mercruiserparts.com
www.go-fast.com
www.bammarine.com
www.cyborgtransmissions.com
It's not alive -www.BoatStuffExpress.com - temporarily retired
Marc
www.mercruiserparts.com
www.go-fast.com
www.bammarine.com
www.cyborgtransmissions.com
It's not alive -www.BoatStuffExpress.com - temporarily retired
Thread
Thread Starter
Forum
Replies
Last Post
tcm07
General Boating Discussion
20
10-03-2008 02:00 PM