1995 Maxum - 4.3lx Mercruiser - Help with block drain plug

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Apr 19, 2019
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Hi..first post, very much a beginner, I took on this project and replaced the rotted 36 gal RDS Aluminum tank, bellows and regular maintenance.

One issue I ran into is the block drain on the starboard side is closed shut with JB-weld and I cannot access with a drill to tap a new hole. I do not want to remove the engine, I am looking for alternatives in order to be able to winterize this boat in the future.

Boat is a freshwater boat in NJ, The JB-weld repair was done before winter and it has been sitting in a garage since: Block is OK. I actually just drained the port side after 6 months in garage and clean water poured out.

Some questions:

1- Is there an another accessible location where I can drill and tap a new hole for a new plug ?
2-Would it be OK to just drain all other hoses and the port side plug, then add Anti-Freeze in using bucket system with muffs while running the engine for a while to replace water with the AF?


https://imgur.com/a/2dxiFrs

Thank you in advance.
 

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Scott06

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Why don't you knock the job off with a chisel and see what the issue is , suspect it's either broken plug or cross threaded. If it's a cheap hollow brass plug that snapped leaving threads inside you can probably get a left hand drill bit to knock it out using a right angle drill. Ultimately drill it out and retap may be required. Might be a P.I.T.A. If someone snapped an easy out off in a busted plug...

Not sure how access is but if you can lift the engine it is easier that you think to pull most smaller boat engines. If in a cruiser below floor different ball game but your typical bow rider is about an hour to pull the engine for access.
 

harringtondav

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I'd invest a few dollars in a right angle air drill. https://www.harborfreight.com/3-8-ei...UaArwuEALw_wcB Get a 7/16 drill (1/4 npt tap drill) and cut it off until it just chucks up with about 3/4" exposed. See if you can access the hole and drill through the expoxy. If the drill is still too long cut it off until you can start it and drill as deep as you can. Then cut off another 7/16 drill to where you can insert it into the partial drill and chuck it up and finish drilling through.

Then see if you can tap through the JB epoxy with a 1/4 pipe tap, and see if you can thread in a 1/4 -1/8 pipe bushing with more JB or epoxy. Let it cure and replace the 1/8 drain plug with teflon tape. It doesn't have to be gorilla tight.

Revision: Same process as above, but start with a 1/8 tap drill ('Q' drill, .332" dia, 21/64"). Less effort and you may be able to get good threads in the bushing already in place (?). If not, use the 7/16" drill.
 
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Bondo

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2-Would it be OK to just drain all other hoses and the port side plug, then add Anti-Freeze in using bucket system with muffs while running the engine for a while to replace water with the AF?

Ayuh,...... Welcome Aboard,....... You'll stand a 50/ 50 chance of a frozen busted block in the future,......
 

Scott Danforth

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Ayuh,...... Welcome Aboard,....... You'll stand a 50/ 50 chance of a frozen busted block in the future,......

more like 99%/1%

seriously, pull the motor, knock off the crappy JB weld job, then take a pipe tap, grind off the end (because you will hit the inner cylinder liner) and chase the threads.
 
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Fine. Sounds like we have a consensus. I will see if I can get a right angle drill to fit... I like all your ideas. I will put a ball valve in so I never have to remove no plug.
 
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Scott Danforth

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use a propane torch or heat gun and pic first. the JB weld softens at about 500F, and you may be able to pick it out with a pic.
 

harringtondav

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Fine. Sounds like we have a consensus. I will see if I can get a right angle drill to fit...

I've been pondering what I'd do. If there isn't enough room for the angle drill thing, you may be able to raise the engine enough without having to pull it. Remove the outdrive. Fairly simple and you should do this at least every two years, if not every year to check the drive shaft and gimbal bearing. Remove the top lock nuts on the front mounts, and the bolts from the rear engine mounts.

Attach a hoist to the front lifting eye, or block a bottle jack under the engine balancer. The exhaust rubber tubes have quite a bit of flex, but you can loosen the hose clamps on each side to give yourself a bit more lift. Hoist or jack the engine up until you get clearance.
 
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I've been pondering what I'd do. If there isn't enough room for the angle drill thing, you may be able to raise the engine enough without having to pull it. Remove the outdrive. Fairly simple and you should do this at least every two years, if not every year to check the drive shaft and gimbal bearing. Remove the top lock nuts on the front mounts, and the bolts from the rear engine mounts.

Attach a hoist to the front lifting eye, or block a bottle jack under the engine balancer. The exhaust rubber tubes have quite a bit of flex, but you can loosen the hose clamps on each side to give yourself a bit more lift. Hoist or jack the engine up until you get clearance.

I just serviced the outdrive and replaced the 10 year old bellows but the bearing was fine (400 hours on this boat on freshwater so not surprised about the bearing) ... I never want to touch it again. I will try the right angle drill, I should have enough room for it and use your idea to tap with 1/4 npt and insert a ball valve with more JB-weld
 

Scott Danforth

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use a proper tap, correct the issue and skip the JB weld.
 

crazy charlie

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Hi..first post, very much a beginner, I took on this project and replaced the rotted 36 gal RDS Aluminum tank, bellows and regular maintenance.

One issue I ran into is the block drain on the starboard side is closed shut with JB-weld and I cannot access with a drill to tap a new hole. I do not want to remove the engine, I am looking for alternatives in order to be able to winterize this boat in the future.
.

Sounds to me like an aweful lot of work for a way to winterize.I have used the Camco kit for approx 30 years now which equates to approx 50 winterizings and it works flawlessly for me.Pull tstat and run 5 gals of Af through the system thru the use of the kit via earmuffs to the drive.My personal preference is to have Af in my block and manifolds for as long as my boat is laid up .I may be in the minority here but this is easy and effective way to winterize including the hotwater heater.Charlie
 

scoflaw

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I'd get the JB off first and determine why it was used in the 1st place, maybe a crack there. Then make a plan
 

crazy charlie

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QUOTE :Boat is a freshwater boat in NJ, The JB-weld repair was done before winter and it has been sitting in a garage since: Block is OK. I actually just drained the port side after 6 months in garage and clean water poured out.END QUOTE I just read the orig post again.I hope your garage temp was above freezing a 3-4 months ago
 
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QUOTE :Boat is a freshwater boat in NJ, The JB-weld repair was done before winter and it has been sitting in a garage since: Block is OK. I actually just drained the port side after 6 months in garage and clean water poured out.END QUOTE I just read the orig post again.I hope your garage temp was above freezing a 3-4 months ago

Garage is heated.
 

Bt Doctur

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Aug 29, 2004
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Simply amazing to see what the late DonS always said , can never do it right, but always do it over
I would raise the engine , drill and retap with a 1/4 quarter inch pipe tap and do it the right way. Failure to properly winterize has led to many a cracked block
 
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I did not have to move the engine, I was able to use a right angle drill. A short drill bit would have been easier but this worked.

A part of the old fitting is still inside, but had enough threads to put the ball valve in.
used high temp epoxy as an extra measure.

As a bonus, I also figured out what's wrong with the fuel gauge.
 

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Scott06

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You can shorten any drill bit with a cutoff wheel.

Glad to see it it worked out , I figured the previous owner buggered it up and Jb welded it to plug the leak.
 
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