DIY Water pump impeller extractor
Manufacture
I have always removed the water pump impeller on my boat
engine at start of winter storage. However, I found that it was quite
difficult to remove the one fitted to the Yanmar 4JH4AE. I made up a
simple tool that works very well and thought that it would be worth
describing as it can be made for a couple of pounds.
I went to a local shop that sells misc. brass & plumbing items and
took my spare impeller. I asked if they had a blanking plug with the
same thread (M18 x 1.5).
- Buy a brass blanking plug with the correct thread. It just looks like a short solid brass threaded bolt that's hollow.
- Find a set screw, bolt etc. with a nut that just fits inside the hollow part of the blanking plug. It doesn't need to be too long, about the thickness of the impeller plus the length of the blanking plug. Something around 40mm should be OK. hand.
- Drill a hole in the centre of the blanking plug, just large enough for the screw/bolt thread.
- Wipe a little grease on the threads of the screw/bolt and push it
through the above hole. Spin on the nut and tighten it down into the
recess in the plug. Push Araldite or similar around the nut to bond it
into place inside the plug. You can put a little PTFE tape on the
protruding threaded section before starting in case you get glue on it.
When it has set you will be able to use it as a puller. I recently
found the diagram below showing a "proper" Yanmar puller confirming
that the internal impeller thread is M18 x 1.5
You could tap a hole to fit an M10 bolt as shown here but I found it
easier to recess a nut in the bottom of a brass plug instead of tapping
the hole.
Use
The impeller on my Yanmar has a threaded section in the hub and removal is just a matter of screwing the tool into this and then turning a screw to pull the impeller out.
- Simply unscrew the screw/bolt almost fully
- Screw the tool into the threaded part of the impeller
- Turn the screw/bolt and this will pull out the impleller
Limitations
This impellor puller works well, but only with genuine
Yanmar Impellors. I think that Jabsco impellors seem identical, but
without the central thread. Narrow nosed mole grips might work with
these. I've also read that Johnson impellers have a different threads
but they may just have meant it wasn't threaded.
