water backup into diesels - it happens

[MV Dana Louise]

We suggest adding this to your maintenance checklist - especially after an extended layup/layover:

Sight check the clear tube running from the exhaust riser anti-siphon valve to the inboard hull vent fitting to make sure it is clear.

If that tube is obstructed [in our case by an insect family], on diesel shutdown the tube cannot break a vacuum in the exhaust loop and seawater is sucked back through the exhaust iriser nto the diesel. You know this has happened when you try to start and get almost no turnover [water does not compress] - or, if you are really unlucky, an engine that starts up on 3 cylinders and mangles the valves, piston etc in the cylinder with the water.

We were lucky on two counts - lots of water, preventing any possibility of starting, and an immediate diagnosis and recovery instructions from Chris Calvert. Three hours later, including the oil change, we were running nicely at 3200 rpm. Whew!

In the future we will not miss checking the $2.00 tubes which could have cost us 10,000X that.

Thank you again, Chris.

[Catrina]

Had marina do my impeller change out. Since I have a canvas cover on the upper station the starboard throttle does not move unless cover is off (it binds the throttle). Mechanic did not know the cause so he just started the engine and ran at idle until water came out the exhaust and shut back down (he says). When I came back to the boat and tried to start engine, luckily it did not start. We found water in oil and in 3 of the cylinders. All is ok now after flushing, pulling injectors and 3 oil changes.

My suspicions: idle did not blow out the anti-siphon 'piddle' tube. Needed a faster speed before any shutdown. When we found the problem and manually blew on the tube it was fine, so not sure whether or not it was plugged or had a small insect inside.

Any thoughts on my suspicions other causes?

I will add a reminder on the throttles to "remove upper canvas and run at faster idle before any shutdown"

Catrina MV-34055