[C320-list] Changing the Impeller

[Robert E. Sloat]

I do what Paul does on my 3GM30F Yanmar.  It is a lot easier to remove the 
pump than to try to get off the backing plate with the pump mounted on the 
motor.

Just close the thru hull for the sea water pump, loosen the pump from the 
engine, take off the hoses from the pump one at a time and drain any water 
into a small can.  (I keep a dry bilge.)  With the pump on a towel in a 
convenient location carefully and remove the backing plate.  The screws are 
slotted so use a screw driver with the widest blade that fits the screws to 
prevent stripping them.  When the plate is off, you then grab the screw in 
the hub of the impeller with a long nose pliers and pull out the impeller. 
You may need to nudge the impeller a little to get it out.  I mark the pump 
on the painted side to show pulley rotation direction and mark the plate so 
it is put back in the same position as when taken off.

Put some glycerin, soap or other water soluble lubricant inside the pump and 
on the impeller and any O rings that seal the plate and install the 
impeller.  I gently rotate the pulley in the direction shown by your 
markings before putting on the plate just to make sure the vanes look fine. 
Starting the engine does the same, but it is an instantaneous  900 rpm. 
Install the plate, the pump, the pulley, then the hoses and tension to spec. 
Make sure the pulley is in the slot on the crankshaft pulley and then 
tension.

Open the thru hull, start up the engine and check for water coming out of 
the exhaust and for leaks at the sea pump.

I remove the impeller when on the tarmac for winter storage and install it 
prior to launch and the drill takes less than 15 minutes.

I believe the Yanmar tool kit has all the metric open-ended wrenches for 
this job, but I use the metric sockets from my on-board tool box.  You can 
tension the pump belt by prying with a long wrench or bar as long a you are 
careful not to scratch or burr the pulley. If you are not confident in doing 
this put a wooden block or a heavy folded towel where the pry bar meets the 
pulley.

The drawings on the instruction sheets that come with the impeller sometimes 
show the impeller rotation in the opposite direction from the 3GM30F which 
can cause confusion, so I just install the impeller and turn the pulley 
according to my markings on the pump.

Bob Sloat
Savannah 894
----- Original Message ----- 
From: "Paul Rickman" <ilove2sail at verizon.net>
To: <C320-List at Catalina320.com>
Sent: Tuesday, July 26, 2011 11:50 AM
Subject: Re: [C320-list] Changing the Impeller, Changing the Oil


I take the hoses off and work on the water pump away from the motor.
Very easy to do and no problem to tension the belts.

Changing the oil with that TOPSIDERS is a snap, your approach is
correct.

Paul
Affinity 657
Bay Bridge Marina
Chesapeake Bay, Maryland





________________________________
From: Jason Alexander <alexander.jason at gmail.com>
To: c320-list <C320-List at catalina320.com>
Sent: Tue, July 26, 2011 12:40:08 PM
Subject: [C320-list] Changing the Impeller, Changing the Oil

Hello,

I have the Euro 3GM30F Yammar in my 320. I was looking at the water
pump last weekend to get the necessary info to order a new impeller
and noticed that the cover plate faces the engine and would appear to
make it very difficult to change the impeller.

What do people do to get a new impeller installed. Do you remove the
pump from the engine? If so is it hard to get the belt tensioned
again?


As for the oil change I have a topsiders oil extractor. Do you just
go down through the dip stick to extract the oil. On the Catalina 28
I had a while ago there was a nice drain hose connected to a fitting
on the bottom of the oil pan. Made changing the oil very simple.

Thanks,
Jason