A question on speed impellers

[SimonFa]

I had to remove and clear the speed impeller last week and thought I had got it back in tightly. However when I went down to the boat this morning I had to bail out about half a bucket of water from the bilges and I managed to get another couple of turns on the thread.

Should I be using something like PTFE tape or something similar to be sure that I have a seal? Looking at it I cant see that it wuld be an eacy operation to switch over from the plug and wrap PTFE tape round before fitting the impeller so if I should what's the best way of doing it?

Thanks in advance,

Simon

 

[Twister_Ken]

I've never had to wrap PTFE on an impeller. I think the clue is that you could get two more turns on the thread. Seems like you hadn't tightened it enough. Half a bucket in a week is a very slow weep, nothing too much to worry about.

 

[vyv_cox]

I guess it depends on the design but mine has an O-ring part way down the cylindrical column that holds the impeller. This does all the sealing, even without the screwed cap. Should yours have one?

 

[SimonFa]

Thanks everyone.

A couple of extra turns again yesterday seems to have secured it. Not sure if I'll ever get it out again though

 

[l'escargot]

Give it a good check over if it isn't glassed in on the inside of the hull. I had similar on a boat some years ago. I had been tightening it down hard and when the boat was out the water I thought I would take the paddle wheel assembly out to replace the o ring, give it all a clean and hopefully get a better seal. When I grasped the securing ring to undo it, the whole of the skin fitting above the securing nut came away in my hand. It had apparently been cracked half way through for some time judging by the calcification on the broken faces and this was where the water had been seeping through. Used to be a particular problem with NASA skin fittings. Could have been awkward if it had come off when I was tightening it down whilst still in the water...

 

[NormanS]

Mine seals on one, or possibly two rubber "O" rings, so it doesn't have to be tightened more than just by hand. A smear of Vaseline, or similar helps.

 

[macd]

A smear of Vaseline, or similar helps.

Silicone grease is usually recommended.
And no sniggering at the back, please.