second stripped drain plug

[captainnate]

I have been using my Starcraft Nova with a mercruiser 120 a little late in the season in Michigan. To protect the block from freezing and cracking I have been draining the water each time. Somewhere along the line the block drain plug got stripped. So I bought a new one and put it in today. Sure enough that one is stripped after one use. Do I need to tap the drain hole? Can I use the same size? This is the part on ebay:

Mercruiser Quicksilver Brass Plug 22 36382 | eBay

Thanks,

Nathan

 

[HT32BSX115]

Re: second stripped drain plug

bought a new one and put it in today. Sure enough that one is stripped after one use. Do I need to tap the drain hole? Can I use the same size? This is the part on ebay:

Mercruiser Quicksilver Brass Plug 22 36382 | eBay

Thanks,

Nathan

Howdy,


If you stripped the hole too much, Yes, you may need to go to the next size plug (that one appears to be 1/4" NPT)you might try a 1/4" tap though and new plug. It'll just screw in a little deeper.

If you do drill it out and re-tap, you would probably go to 3/8" NPT............ The taps usually have the drill size stamped on them......
You can buy a tap at most hardware stores or plumbing supply stores........... and you can get a brass pipe plug there too. You do not have to get the "Mercury model"..... It's just a common plumbing fitting.

Now, keep away from that 12" Crescent wrench or 24" "breaker-bar"!!!!!! Those plugs DO NOT have to be very tight! There's essentially NO force trying to unscrew them!

So wrap some T-tape or slop some plumbing "dope" on it and tighten it using minimum torque!


Regards,




Rick

 

[thumpar]

Re: second stripped drain plug

My 120 had a valve instead of a plug on the lower drain so all I had to do was twist to drain the block. It kind of looked like a wing nut. Not sure what the real name is but it made things easy.

 

[Bondo]

Re: second stripped drain plug

I have been using my Starcraft Nova with a mercruiser 120 a little late in the season in Michigan. To protect the block from freezing and cracking I have been draining the water each time. Somewhere along the line the block drain plug got stripped. So I bought a new one and put it in today. Sure enough that one is stripped after one use. Do I need to tap the drain hole? Can I use the same size? This is the part on ebay:

Mercruiser Quicksilver Brass Plug 22 36382 | eBay

Thanks,

Nathan

Ayuh,.... The Block drain oughta be 1/4" pipe thread,...

That brass pipe plug is a couple bucks or less at yer local hardware store,...

I donno if you can run a 1/4" pipe tap in deep enough or not,... it's worth a try,...
Just don't try too hard to go too deep,...
It'll be pushin' on the inner wall of the Oil pan area,...
Worse comes to worst, grind the end of the tap off where needed,...
Just don't tap Bigger than the plug,...
They're both Tapered ya know,...

Ya might be able to clean up the threads enough, with just a little pick/ file, etc,...
A burr on the outer edge might not need the tap to clean it up,...

 

[Walt T]

Re: second stripped drain plug

I once saw a pretty smart jury rig, the guy had exact same problem, stripped pipe thread so he cut a piece of rubber tubing probably 5/16 fuel line or 1/4 maybe and then with that in the hole screwed a bolt into the hose which expanded it and it stayed put for years until we pulled the engine for one of my jury rig overhauls. He said he could remove the bolt and the hose and it would all drain then he'd stick it all back in. He didn't really have a choice as there was very little room to get a tap in there.

 

[ken51k]

Re: second stripped drain plug

I had this problem also, I ran a 1/4 inch tap through it then I put (with locktight) a short piece of 1/4 inch pipe in the block and just put a cap on the pipe. The locktight held the pipe in the block very nicely and all I have to do is remove the cap off the pipe when I want to drain it. I'll hold the pipe with a pair of pliers to prevent it from moving when I take the cap off.

 

[captainnate]

Re: second stripped drain plug

Thanks for all the help. Guess it is time to take a trip to the hardware store.

 

[alldodge]

Re: second stripped drain plug

Suggest using one of these (Rad Drain Plug) and some pipe dope. Looks like you already stripped it so unless your going to go big (Not a good idea with cast iron), use one of these and get it sealed then you have an easy drain.

Other way is to get a 1/4 to 3/8 adapter, then get a bushing and Blue Drain Plug

 

[thumpar]

Re: second stripped drain plug

Suggest using one of these (Rad Drain Plug) and some pipe dope. Looks like you already stripped it so unless your going to go big (Not a good idea with cast iron), use one of these and get it sealed then you have an easy drain.

Other way is to get a 1/4 to 3/8 adapter, then get a bushing and Blue Drain Plug

The second drain down looks exactly like what I had on my 120.

 

[superbenk]

Re: second stripped drain plug

To the guy asking about the name if the wing nut shaped drain it's called a seacock.

I don't like the pipe extension idea because rust can get trapped at the block side of the pipe & clog the drain which could leave water in there to freeze. If you're doing that make sure you're probing all the way back to the entrance of the pipe to ensure everything drains.

Same with the seacock. The holes on those are small so they tend to clog easy. Make sure you're getting all that water out. When I had those, I'd actually just remove them completely to drain and treat them like a plug. Always run some stiff wire in the hole to make sure it's clear.

 

[Scott Danforth]

Re: second stripped drain plug

Its actually draincock in this stituation. A seacock is specific to a valve used to block seawater at a thru-hull fitting.

 

[alldodge]

Re: second stripped drain plug

The plug is at the bottom of the water jacket, I believe if any water is left by the pipe extension, there is so little to not cause an issue. Merc design and have not heard anyone having any problems.

 

[ziggy]

Re: second stripped drain plug

The plug is at the bottom of the water jacket, I believe if any water is left by the pipe extension, there is so little to not cause an issue. Merc design and have not heard anyone having any problems.

yep. that's the set up i got.

i've not had any problem with it. though i do as suggested above about holding onto the extension while operating the t. specially the first time i turn it in fall after not using it for a while.

i'm on my second one of these on two different L6 engines. the first one, the stand up pipe did get stripped by the previous owner (my dad, )he used some kinda goop to reduce the hole size. that repair never worked real well and it always leaked + when ya operated the t valve ya had to be really careful not to move the pipe or it'd start leaking worse.

i'd think the best type of repair would be a next size up pipe thread, then reduce it to the standerd size plug. if the block will let ya tap a new one size up screw threads. that would be my last option i'd try. first it try chasing the pipe threads that are already there.

my biggest grip about the drain **** set up is i've never been able to prob either of the ones i had. i always worry about rust scale build up not allowing me to completely drain my block. though i've always been able to drain it completely w/o probing the hole. only reason i think i drain it completely is, that over time i've drained it enough times to know how much comes out of it. if i get the proper amount out i believe i'm completely dry. i still would like to probe it though. it'd make me feel better. but with the t **** valve. i've not had that option.

 

[HT32BSX115]

Re: second stripped drain plug

i'd think the best type of repair would be a next size up pipe thread, then reduce it to the standerd size plug. if the block will let ya tap a new one size up screw threads. that would be my last option i'd try.

I wouldn't hesitate to do that except WITHOUT the reducer. A 3/8" NPT (pipe) tap is pretty short, With a slightly bigger hole, you'll have an easier time getting rust flakes to pass through ...... You could also put a 3/8" NPT ball valve there.



Once it's open for draining, you can still pass a piece of wire or small screwdriver through it into the water jacket to poke the rust flakes around!

If the handle is in the way, you can shorten it or remove it and use a wrench to open and close it.

Let me also add that you can probably just get a 1/4" tap and re-thread the hole a little deeper. (the tap is tapered)

How much deeper will depend on how much room you have behind. Use a screwdriver, wire etc to check the depth. If you cannot go any deeper with a 1/4" tap, you have to either use the next size pipe tap (3/8") or go with the next size (up) metric tap .

Metric taps and dies are not used as much and you will have a slightly harder time finding them....

 

[captainnate]

Re: second stripped drain plug

It has been a while, but I thought I would post an update just in case somebody stumbles upon this subject in the future. I bought a tap and new plug from the hardware store. I put a little oil on the tap and screw it into the drain hole. I turn it a few times with a wrench, and then unscrewed the tap. I really didn't use much force; it more or less just need to be cleaned out. The new plug went in very easily, and I made sure I only turned it about a 1/4 turn with a wrench after hand tightening. The plug isn't loose, and I'm sure it will not work itself out. However, I would still rather error on too loose instead of too tight.

Thanks for all your ideas/suggestions. Somebody on this site always has the answer.