Drain plug problem this weekend

[randmhall]

Interesting problem this weekend. I am cruising the lake and start hearing a squeaking from the engine compartment. When I stop to investigate, upon opening the hatch there is water spraying. Turns out that the little blue drain plug on the thermostat housing broke off (vibration?) and was discharging water all over the engine. Fortunately for me, water on the drive belt makes it squeal, or I might not have noticed until there was a real problem! If I kept the speed low, the volume was low enough that the bilge pump was able to keep up until I returned to my dock, about 3 miles away.

The knob off the plug was found in the bilge, but the threaded section was stuck in the thermostat housing. Real stuck. Upon talking to my local mechanic, I was able to get it out in pieces with a screwdriver, and then chased the threads with a 1/2" course tap to clean them out. The plastic from the plug was exceptionally brittle.

I replaced the plug with a new one, as well as replaced the lower plug for good measure. Boat ran fine the rest of the weekend!

Lessons learned...
Listen to you machinery. It takes to you when there is a problem.
When it comes to bilge pumps, bigger is better.

Just thought I would pass it on.

 

[Creekwood]

Those blue plugs deteriorate over time. They also get put in and out during winterization and if over-tightened can break off. They are hollow in the center so they stream water out if they break off. Its a good idea to have a few extra ones around in your spare parts kit for that reason.

I had a similar issue this weekend, but with a heater hose to the block. I was out for several hours Saturday and on the way back in i noticed the light on the bilge pump switch come on and then shut off. It stayed off so I went back to the marina and checked it out at the slip. I quickly found that the hose clamp on the water heater hose was not installed properly (loose and misaligned). I had my impellers replaced by the marina two weeks ago. A quick fix.

 

[RollerCoastr]

I keep meaning to look for a way to buy a supply in bulk - replace them all and keep spares. I snapped one off a few years ago and paid "retail". :smt013

 

[randmhall]

Amazon sells 5 packs, both Sierra, and some knock off brand. I assume the Sierra would be as good as the Mercruiser?