Off the wall question?

JSMoore

Petty Officer 2nd Class
Joined
Sep 5, 2010
Messages
110
I'm in the process of winterizing a 1987 OMC Cobra, 4.3 with closed water cooling system. I changed the oil, drained the heat exchanger, manifolds and PS cooler. I've also got all the plugs out and hoses off.

I needed to start the motor after the oil change for just a minute or so, (on the muffs, of course), to circulate the oil through the engine and new oil filter. When I started it, I got a REAL healthy stream of water from the raw water hose :D. But, there was a different sound to the motor. And, upon closer check, I had LOTS of raw exhaust gas and pressure coming out of the raw water entry fittings on the front of the exhaust manifolds, (Old style batwings). See the picture attached:


In the absence of raw water flowing through the manifold water jackets and out the exhaust, I suppose exhaust gas could come back through the water jacket. But, as large as the exhaust system is, I wouldn't think you get much back through there.

Should I be seeing significant exhaust pressure coming out these fittings?
Thanks!
JSM
 

Attachments

  • 43OMC.JPG
    43OMC.JPG
    112 KB · Views: 0

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,464
Re: Off the wall question?

Should I be seeing significant exhaust pressure coming out these fittings?

Ayuh,.... With No water, 'n No water flow,..?? Yes...
 

JSMoore

Petty Officer 2nd Class
Joined
Sep 5, 2010
Messages
110
Re: Off the wall question?

Thanks Bond-O. I know these manifolds are past due for replacement. And, I'll be replacing them this winter anyway. I was just kinda surprised at how much exhaust I was getting there.
JSM
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,464
Re: Off the wall question?

I know these manifolds are past due for replacement.

Ayuh,... Those bat-wing manifolds were Overdue for replacement the Day they came off the assembly line...

You don't know how Lucky you are you're not replacin' the Motor too...
 

JSMoore

Petty Officer 2nd Class
Joined
Sep 5, 2010
Messages
110
Re: Off the wall question?

Ayuh,... Those bat-wing manifolds were Overdue for replacement the Day they came off the assembly line...

You don't know how Lucky you are you're not replacin' the Motor too...

Oh, I know. I'm going to try and nurse the motor through another year, then replace that as well. It's a race between the motor and the drive, though. The drive is OK for now, but begging to be replaced with a SEI conversion.

I love my boat! It keeps me from having to decide what I'd do with all that excess wealth I'd build up without it! :D

Thanks Again!
JSM
 
Top