Yanmar queries

[richardabeattie]

I did my engine lay up today - it's a Yanmar 2GM20 - and found myself puzzled by some details:

1. The boat is ashore. When I opened the plastic water plug on the starboard side of the engine no water came out even when I poked about inside with a litle screwdriver to break up any crud that might have been holding back the water. Yet the engine had been running well when I brought her in and plenty of water flowed out when I subsequently took the engine anodes out. So why no water from the water plug?

2. The after anode on the engine showed some deterioration but still plenty of zinc left. But the starboard engine anode (fitted in a place selected by the engine's designer on the basis that it would amuse his friends when he told them in the pub) was as new. No sign of any metal loss. Why is this thus?

3. Now this is a really silly one. My impeller cover plate has a useful arrow on it to show direction of water flow. Both ends of the arrow have an arrow head. Both ends are helpfully engraved "In". Do I have the first Alternating Current impeller in the country or is this another Yanmar tease? As far as I can see as long as the cover plate is on the right way round, (ie working side inwards, painted side out!) it does not matter which way is up.

 

[fireball]

1 - did you remove the anodes before the water plug? anyway - where is the water plug - I've not seen that one yet!
2 - no idea - I'll check ours at some point this winter - replaced both this year so it'll be a fair test...
3 - erm - can't recall, I just bunged it back on, ran the water through - it leaked, stopped it all, turned it round and ran again - no leak = leave well alone! /forums/images/graemlins/smile.gif

 

[richardabeattie]

... but when I subsequently removed the anodes ...!

 

[earlybird]

1. Either you didn't poke enough, or air couldn't get in to allow the water to run out, did it run out after you removed an anode? Also, try attaching a rubber tube and blowing hard into it to disturb the crud.
2. A 2GM20 that I owned for 6 years was very light on anodes, I wouldn't worry too much.
3. I think that the arrows are meant to indicate which connection is the inlet when the pump rotates in that particular direction. ( You don't have a choice of course).

 

[richardabeattie]

Um. Yes. The screwdriver went well in but you may have a good point about there beng no way for the air to get in. Of course the anode holes are lot bigger so they probably aerate themselves. Next time I'll take the top (after) anode out first and then see if that wakes up the water plug.

 

[Capt_Scarlet]

My water tap was bunged up throughout it's length with hard crusted muck - I'm not surprised no water came out from your engine tap.