blown formula

Brad, ya' think he can get by with two???? roflmao That was a good one!!

Maybe he meant to say- except the exhaust...what do you think??

Brad Perry

I hope he meant WITH exhaust....I just picked up a new battery for my screw-gun

I think we could get away with a sharp hit from one of those big waffle hammers on the bottom of the buckets for an orifice to get the return hose through...

Don't get me started on where we could get the hose back into the engine compartment.....it involves my sawsall

Panther

You could have fresh water cooling run thru the exhaust. They do this on F/W cooled Mercs, and F/W cooled Crusaders.

All you would have to do is plumb the Manifolds in with the fresh water cooling system. The manifold is then completely isolated from the riser. The riser (or Tailpipe) would still be used to expell the Raw water into the exhaust.

Even when a merc manifold or crusader manifold is used all they do is use two gaskets and a stainless plate in between to isolate the manifold and the riser.

A Gil riser, or even a CMI system would probably be easier. Could be something to look into?????? I never tried it myself.

Brad Perry

How will that prevent reversion?

Panther

This is just a hunch, but if he didn't shut the motor down before he pulled it up the ramp this would have never have happened. Even if the starter kicked back when the boat was sitting level in the water, it wouldn't have sucked the water back in the exhaust. Because the boat was so deep from sitting on the trailer it either flooded the manifold with water, or when the starter kicked back it sucked it in because the water was pretty far up in the exhaust to suck it in.

I have very large public ramp near by, and on Sunday afternoons after a nice day on the boat, I take a ride over and watch all the these guys taking their boats in and out of the water. It's really a comedy show. People forget to leave the safety chain on when launching, forget the plug, "shut the motor down while the transom is buried in the water" etc..

Panther

I read the first thread again. Were you waiting for the guy to put the trailer into the water, or were you waiting for your buddy while you were already on the trailer.

If you were waiting for the trailer, my theory is incorrect. Sorry about the misconfusion if I am wrong.

florida gator

Many mechanics have looked at me like I am crazy when I explaine this very problem. I have had it happen a few times, and know the noise you are talking about well. I have same motor with OMC Cobra drive. I have been talked out of a few thousand dollars by techs guessing at what it might be. So far; replaced manifolds and risers, replaced flappers, had engine tuned and timing set, replaced flappers again.

Every tech I describe this to claims to know exactly what the problem is, yet it has still not been corrected. It does not happen often, and I never know when it will happen. Last time was July 4.

Please keep me in mind when you do get this resolved.

Lazze

I was wrong about FW cooling should prevent it ( just a temporary brainloss) . The boat was not on the trailer´, just foating at normal level. If you look at my earlier post my mech stated that it was not all uncommon. Thru hull exhaust iis propably better in this case, then its only sucking air...

Offshore Addiction

sometimes if the boat is still underway,and the idles still high and you shut the ignition off itll suck water back up the exhaust.....