Off the wall question?

[JSMoore]

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 . 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

 

[Bondo]

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]

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]

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]

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!

Thanks Again!
JSM