"jzlatar-genesis" wrote in message
om...
I have a yanmar 2GM20F installed in a Plenamar 300 with
the following
problem, No water coming out of the exhaust pipe with the
result of
overheating and the pump is working with a new impeller,
what could be
the reason for it and the solution.
Thanks in advance
Jzlatar-geminis

1 Check salt water intake cock is open

2 Check intake filter is not blocked (jelly fish,
seaweed, plastic)

3 Open intake cock with filter out, check water flows. If
it doesn't, there's an external blockage. If it flows, go to
4.

4 Detach outlet pipe from salt water pump, turn engine
over (stop switch held in), water should flow out. if it
does, go to 5.

4a If it doesn't, check priming height. Some pumps aren't
very good at priming more than 2m. If priming height is OK,
take cover of pump off and check pump vanes are turning. If
vanes are turning, replace cover with screws only gently
tightened and see if water comes out. If it does, tighten up
and see if flow stops. If flow stops you've got a sheer
failure in the pump impeller. The cause may be an overlength
impeller, an impeller tight on its spindle, or an under
thickness gasket.

5 If 4 shows good water flow, detach salt outlet from
heat exchanger manifold, turn over and see if there's flow.
If not, you have blockage at the heat exchanger inlet end
(quite common) due to build up of carbonates. Clean out with
reverse flow. If there's good flow, go to 6.

6 Check the exhaust elbow for carbonate build up and
corrosion.

That should find the problem for you. Have fun. It's called
yachting.
--
JimB
Yacht Rapaz, sadly for sale:

http://homepage.ntlworld.com/jim.bae...ecification.ht
m
jim(dot)baerselman(at)ntlworld(dot)com