Drain Plug/Knock Sensor Problem...Retap Time?

[Fishman]

Summerizing the boat today in WI...new record- March 31st! Ice almost gone!

I can't get the drain plug and the knock sensor to go back into their holes. I stripped out the brass drain plug and went to Ace to buy a new one.....

Anyone know if I need to retap the holes? Also, it seems I only turned these 1/2 turn to a full turn to get them out.

I'd really appreciate any advise here...thanks. Fishman

[iwakeboard]

Summerizing the boat today in WI...new record- March 31st! Ice almost gone!

I can't get the drain plug and the knock sensor to go back into their holes. I stripped out the brass drain plug and went to Ace to buy a new one.....

Anyone know if I need to retap the holes? Also, it seems I only turned these 1/2 turn to a full turn to get them out.

I'd really appreciate any advise here...thanks. Fishman


I summerized my 24SSV just the week before last and asked my tech the EXACT same question. I think the starboard side plug needed a 9/16 (maybe a 7/16?) wrench and the port side (noc-sensor) needed a 7/8. He told me you barely have to give these things a full turn, that they won't go all the way in there and not to try to do that. My tech worked at the Supra/Moomba dealer as their main tech for years before they went under and still helps me out, so I absolutely trust his advice. Assuming your engine works the same way, you should be in good shape! I took mine to the lake the next day, after putting the plugs back in, and ran her around. Checked both the plugs and solid as could be. I had a guy winterize it last year and he told me that they were barely in there as well, so they were that way for a whole season.

[Fishman]

Thanks a lot. But, I can't seem to get either the Knock Sensor OR the drain plug to grab any theads at all....so I can't even get a half turn on them...So, my question is whether I need to use a tapping tool to try to retap the holes or is there another solution I should try....thanks again.

[iwakeboard]

Thanks a lot. But, I can't seem to get either the Knock Sensor OR the drain plug to grab any theads at all....so I can't even get a half turn on them...So, my question is whether I need to use a tapping tool to try to retap the holes or is there another solution I should try....thanks again.


I'm not sure if that's what you should do or not, unfortunately. I'm not sure if it's cheaper to buy a tap or a new plug/noc sensor? How long did you try to get the thread to start? It took me a long time (~10-12 minutes) to get both of them to start. For a while I thought the guy who winterized my boat had forgotten to take out the plug and it had blown out (looked around the bilge for the "blown out plug") and cracked my block, and that the plug I was holding was for somewhere else because I didn't think it would ever fit/start threading, hahaha.

[Fishman]

I think thats why we all have codenames on these forums. Because we've all done stupid stuff like that....and the forums give us place to admit our stupidity without anyone knowing our real names! Hilarious.

I think I'll go the retap route and let you know how it goes....thanks again.

[beast 496]

the tap you will need is a 1/4" NPT This a pipe tap the threads are tapered. The problem you are having is the block is cast iron and the threads rust. When you get the drains tapped and cleaned out buy a brass bushing for the same thread, 1/4" male to 1/4 female. Thread in the bushing first. When winterizing the bushing stays in the block and you just remove the drain plugs, knock sensor. Note some of the knock sensors are also just made out of steel. they will rust also, when threads become damaged either retap or replace. Al