In article ,
"Jeffrey P. Vasquez"
wrote:

I recently did a standard maintenance replacement of a raw water impeller
on a Yanmar 2GM diesel. Everything seemed straightfoward, part for part,
no leakage, everything went back together straight away and test runs at
the dock were nominal.

However, during a move to a new slip the engine alarm went off. A
subsequent check revealed nothing.

Try the impeller you took out -- it sounds like it was working before.
Happened to us once. We got just enough flow for idle power.

After that, I'd dismount the pump, leaving the input hose on, put the
output into a bucket and power it with a drill. If you get good output,
then it's downstream.

We also found out that we have about 5 minutes' cruise power with no raw
water flow: Takes that long for the fresh water loop to get hot.
Probably takes longer if you have a domestic hot water tank in the loop.

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/