Get a copy of "Boatowner's Mechanical & Electrical Manual: How to Maintain,
Repair, and Improve Your Boat's Essential Systems" by Nigel Calder. He does
a great job of explaining with illustrations and alternatives; e.g. instead
of a vacuum breaker he likes a small tubing venting into the cockpit. If it
isn't wet, shut off the engine.

Roger

http://home.insightbb.com/~derbyrm

"Jim and Becky" wrote in message
...

I've seen some water lift mufflers at www.marineexhaust.com. , but this is
a 420 hp engine.
Can you give a brief explanation of Injection Elbow, Vacum Breaker, and
wet
loop?