Re: Mercruiser Exhaust Tube Question
Hmmm.... is this done on boats? Open exhaust, thru-hull into water?
If the pressure is high enough at idle, the engine shouldn't stall (thinking out loud). On a thru prop set up, I would think it's designed to flow fast enough with enough pressure to prevent a stall.
On trucks, it's common to see tips turned sideways so that they aren't submerged when launching/retrieving down a boat ramp (possibly stalling the truck). That makes me wonder about a regular exhaust tip being submerged.
The sideways-bent exhaust doesn't prevent the exhaust from being submerged that much, and even when you submerge the exhaust it won't stall the truck, you just get exhaust bubbles coming out of the water, just like the boat.
Frisco, you are basically talking about switching from thru-prop to thru-hull exhaust, and yes it can be done. You would need a bit of custom piping to make everything work, but that is in essence a normal way to get thru-hull. The exhaust will be much louder, and you'll need special tips with external flappers to keep water from going back up the exhaust when you slow down and your wake comes back against the boat. Seems like a lot of work for very little gain in performance. The manifolds is what causes the lower performance for the most part, not going through the prop.
You would need to pull the engine, and remove the exhaust y-tube and install a block-off plate to do it correctly. You could try and simply cap off the y-tube openings and leave it in there, but that would be a big, heavy peice of tubing serving no other function than to get in the way and be a possible source for a water leak.
I would install the exhaust tube and run it through the leg if I were you.
