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Water Drain Plug Access

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pineycreekroad

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"I have a Mercrusier 5.0 that

"I have a Mercrusier 5.0 that has 6 water drain plugs. Three of the plugs are very hard to reach. I want to extend my boating season by draining the water after each use in the Spring and Fall. Does anyone know a way to attach a short length of hose to those drain outlets so that they could be accessed easier? Or any other ideas how to make the draining process easier? Any help would be great!

Thanks,
Mike"
 
If there is room you can remov

If there is room you can remove the drain plugs and insert a short extension and fitting. Pull a drain plug and visit a hardware store. Use brass pipe and fittings. Just make sure the fitting won't interfere with any hoses or parts when the engine moves.
 
"Thanks for the suggestion but

"Thanks for the suggestion but have tried that already. First of all, the small blue plastic drain plug has a very course thread on it and it does not match up to any standard pipe type threads. Secondly, I need something flexible so that I can put my hand on the end of it and pull it up to take off a cap or plug. One drain plug sits on the very underneath of the bilge area and is very hard to get to. Any other ideas?

Thanks,
Mike"
 
"Mike:

The plastic plugs wi

"Mike:

The plastic plugs will fall apart in a few years. I'd get rid of them. That requires replacing the plug bases or tees with brass ones. Wait until you are out a few miles and one breaks off and starts dumping water in the bilge.

For the one you want a hose, replace the plug base with a short brass 90 deg. nipple and attach a heavy duty hose to it with double SS screw band clamps. On the other end install another nipple with female pipe threads on it and a brass plug with some never seize. Drill a 3/16" hole thru the head of the plug so it can be be turned with a small screwdriver. You could insert an "S" hook in the hole and attach a piece of rope to it and use the "S" hook as a handle."
 
"Guy;

You have explained ex

"Guy;

You have explained exactly what I intend to do. It is more or less like the the same set-up as the hose system for the oil drain. I still do not understand where I get the brass parts?? For sure, the tread type is NOT standard pipe tread. I'm pretty mechanical and know that a standard brass fitting will not match up. Where should I look for the correct brass part?

Thanks so much for your help!!!

Mike"
 
"If there is a plug base screw

"If there is a plug base screwed into the block for the plastic plug, you have to change the bases. The bases will be tapered pipe thread. CAREFULLY remove one and go to a plumbing or hardware store. Don't use cheap Chinese made cast parts. You might try a marine dealer for the fittings. Just make sure he sells you brass and not aluminum. Seal threads with white pipe sealant that contains teflon--not the tape. You'll have to change the coolant hose fittings, "T"s and elbows, that have plastic drain plugs to brass to get rid of the plastic crap."
 
"There are no plug bases. The

"There are no plug bases. The threads are tapped directly into the block and manifolds. I certainly do not understand why Mercury would use such an odd thread size for these drain ports. Even the boat dealers don't know what thread size it is or where to find a brass part that fits. Anyway, at this point I have had no luck on finding the correct brass fittings. One boat dealer suggested NAPA auto parts. If anyone on this board has any other ideas....please let me know."
 
"I now know the thread size of

"I now know the thread size of those blue plastic plugs. They are SAE size 1/2" x 13, which is the size of a standard 1/2" machine bolt. So wherever you can find a brass hose barb with those threads is where you can solve this problem. Who knows where that will be!!!!"
 
Find a local small machine job

Find a local small machine job shop and take along with you one of the plastic plugs and several different oversized brass nipples. For a small fee one of the guys could cut the thread to fit.

Why did Mercruiser start using these junk plugs? The bottom line! They like the big three will do anything they can at the expense of the consumer to keep their profit margin high.

Not until they get enough complaints from us will they change the product to a more reliable part. Write their customer service about your issue and make a stink about the difficulty you are having. Squeaking wheels eventually get oiled.
 
That sounds like a good idea a

That sounds like a good idea and may be what I end up doing. I have also thought about just buying some brass tube stock and the correct die and tapping my own. I don't see many other options.
Thanks for your help and suggestions!

Mike
 
"I have been thinking about th

"I have been thinking about the same idea, but haven't acted on it, other than find out there is no quick answer due to the coarse thread size. The drain plug on the starboard side on my 2001 210BR is threaded into a T fitting, which also holds the heat sensor. I haven't pulled the T fitting yet to see what thread size of that fitting where it goes into the block. Have you looked at that to see if it is SAE (I think it may also be called UNC) or may be NPT(hope of hopes)? I believe there is also a T fitting on the port side as well. And I have never found the 6th one under the block-I always wondered where No. 6 was!! (I have had no problem with freezing without draining No.6, but I add a lot of antifreeze)
We have also discussed the machining idea, but it may be price-prohibitive. I know some of the newer Mercruisers have a single-point drain system, like the oil. Maybe Merc has parts for that system that would fit. I'm hoping your successful and can share your success!"
 
"The other problem is that the

"The other problem is that the ID on the Merc fitting is 1/2" (although if the thread was finer it would be called a 1/4" NPT-go figure on how they name sizes). The other hoses (from the block to the heater) on my boat are 5/8" heater hose. Standard heater hose connections are 3/8 and 5/8!! not 1/2 inch. So you might need to use a metal lathe to reduce the diameter of the SAE fitting and have the larger diameter on the other end of the fitting for the hose barb (or find 1/2 hose fittings?) Sounds like a lot of work, but those 3 plugs are awfully hard to reach. Oh, and I carry spares of the blue plugs for when I break one trying to take it out, which happens quite regularly. They cost $4.60 Cdn each (probably less in the US)"
 
The blue plastic plugs only ne

The blue plastic plugs only need to be finger tight. I use a dab of never seize on the threads to make sure I can get them out.
 
"B. Hudson--- Here is where I&

"B. Hudson--- Here is where I'm at with this so far... First of all I want to say that for an absolute fact, the thread size on the plugs and the openings that they fit into is SAE 1/2" x 13. That is for sure and that is a standard thread for any common 1/2 bolt that you can find at any hardware. I found a place in Denver that had 1/2" brass bolts. They only had 1/2" x 3" long, which was ok for my test project. The 3" brass bolt had about 2" of thread on it and after I cut the head off of the bolt, it had about 5/8" of clear shaft on it. The 2" of thread is way more than you need to screw into the block (or wherever you need to use this). So after I cut the head off the bolt, I put oppsite end in a vise and used a drill press to drill a 1/4" hole through the entire bolt. Brass is soft and with some oil and a sharp bit it drill pretty easy. I drilled a total of 2 1/2" from end to end. The results were fair in that on the end where the bit came through was not perfectly centered. I still think it will work just fine though. It may be better to cut about 1" off of the threaded end of the bolt to make a shorter drill run and that should help to keep it more on center. With just a vise and a drill press it is hard to get the bolt set exactly straight side to side. I put on 2 nuts to protect the threads and hold it better in the drill press vise. I'm sure a machine shop could easily drill a perfect hole through the bolt for not much money. These bolts were sort of hard to find, but not impossible. Stainless steel were around but I'm sure much harder to drill. Now for the hose...I have not gone out to find the hose, but I don't think that will be an issue. There are many sizes of automotive hoses and I know I can find one that will work. I will use a common brass barbed fitting on the terminal end with a cap or plug. The sixth and toughest drain plug on my boat is under what I believe is the fuel cooler. That is almost impossible to get to. I asked a Mercury mechanic about it and he said often they don't even remove that plug, they remove the hose to the area, blow it out with air and pour in the antifreeze. That's fine if it is your final winterization. One other note...I checked into the 1 point drain system retro-fit...there would need to be many parts changed to make the conversion and most say it can't be done or if so....very expensive $1000.00+ I think if you only want to do 1-3 drain ports this drilled out brass bolt concept might work. What do you think?"
 
"In order to make it easier to

"In order to make it easier to install and have a base, solder a thin brass nut at the depth you need for the block. I would also consider soldering the nipple on it. Use high strength loctite to seal the threads in the block."
 
I don't think you will fin

I don't think you will find a "thin" brass nut anywhere. The brass bolts and standard nuts are hard enough to get. I planned on using the standard nut as a base and a way to install it. I don't understand your concept on the nipple? The hose will easily be clomped on to the smooth shaft part of the bolt assembly. Why would you want to loctite these into the block?
 
"Sorry; thought you were using

"Sorry; thought you were using a nipple with it w/o a smooth section. Loctite a permanent installation to prevent degradation of the threaded block opening from vibration, etc. There is also a flexible aviation grade Permatex that will hold it in place and allow removal or use a teflon based plumbing putty that will hold it in place."
 
"Here's what I did- I foun

"Here's what I did- I found a brass nipple 2 inches long, took it to my friendly machinist, who charged me $40 to tak e 3 nipples, cut off one end, and thread it to the SAE thread. So one end is now SAE and one end NPT, which then connects to standard hose fittings. I screwed in an elbow, attached a barb end, and put on a piece of 3/8 hose, then a barb fitting on the other end with a NPT brass plug. I have a slight problem in that there are a few drips, which I will fix next year when it's warmer, with some RTV sealant for the threads. I used white pipe dope, and it's not stellar. I don't like the idea of high-strength Loctite. it would take heat to release it, and that's a bad place for any type of heat.
Now my connections are in the front of the bilge-draining the block is determined by the length of time it takes the water to drain, not by how long it takes you to become a contortionist and remove the blue plugs. I also have a heater, and I put a flush T in the upper hose to the heater, and added a shutoff between the flush T and the block. So I can shut off the hose, blow air through the flushT to clear the hoses to the heater, then put antifreeze thru the flushT with the shutoff still closed, and have antifreeze in the heater hose. I then open the shutoff, and pour antifreeze down the flushT into the block until it drains out the first blue plug on the front of the engine, then I close that drain cock, and continue pouring antifreeze until it drains out my new hoses from the lower part of the block. And then I'm done. It was so easy, I almost took my boat out again after winterizing it this fall!"
 
B Hudson,

What size diameter nipple? Was 1/4" able to get 1/2 x 13 threads tapped to the outside without possible vibration breakage from being too thin walled?

Thanks
 
17 year old thread. I was trying to figure out how to do the same thing but with regular brass drain plugs on my old OMC 4.3. Just to extend the drains a bit to make it easier.
 
for the block drains, remove the blue fitting and base install 1/4 pipe barbed nipple, use hose to a easy location,plug hose end
 
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