Stopped up what??

Nothing is wrong with Ms. Bettencourt's old Kubota engine. Even her fuel injectors, which I removed and had tested last week, are in excellent condition. Then why wouldn't she run?

Her exhaust was stopped up. More specifically, it was this thing, (pictured here) called an exhaust mixing elbow.

When this elbow is working like it is supposed to, exhaust gasses from the engine enter it though the fitting in the lower right of this photo. At the same time, seawater from an on-board water pump comes in the brass fitting at the top.

This results in the exhaust gasses being mixed with cooling water, the sum of which is then ejected out the tube at the lower left, which is hooked up to a 2" hose that goes to a muffler then out the back of the boat.

The elbow stoppage was discovered by Kubota technicians, whom I had called in from the local tractor company after everything else I could think of failed. The fact that it took two certified technicians two visits to figure this out eased the hurt to my amateur diesel mechanic ego just a little.

So, how do we know that nothing is wrong with the engine? Simple. After the techs removed this elbow, they started her up and ran the engine up to full power. Ran beautifully.

Unfortunately, with the exhaust disconnected, all that black, sooty, oily, diesel exhaust had no place to go except all over my pristine, just painted, snow white middle cabin, including seats, decks, bulkheads, dashboard and the instrument panel.

Sigh. The four-day cleanup is just about finished.

My cruise buddy Major and I disassembled the elbow and mounting flange yesterday and, briefly, I thought we could clean the elbow out and put it back to work. Alas, that is not to be. The inside part of the casting appears to include a baffle or internal chamber designed to keep injected water from getting back into the engine. The baffle or chamber wall is mostly corroded away. I think it would be a bad mistake to put this chunk of iron back into service.

Now, I'm on the hunt for a replacement mixing elbow. Please look in again. I'll post an update when there is something to report.