Merc Lower Gear Case Cracked

[Cheetah 20]

Hello and thank everyone in advance for your help.Has anyone ever tried to use JB weld on a crack .The crack is approx. 4" long and 2" above the fill/drain plug.

 

[Haut Medoc]

Re: Merc Lower Gear Case Cracked

I doubt if it will hold for long, if at all....
What caused the crack?.....​

 

[Cheetah 20]

Re: Merc Lower Gear Case Cracked

I think water got in through the cover.

 

[Windykid]

Re: Merc Lower Gear Case Cracked

Have it welded!

 

[Haut Medoc]

Re: Merc Lower Gear Case Cracked

You can try to have it welded, but if water got in you have more issues than that....
Like finding out how the water got in, bellows or ?....

At best you can weld the crack, have the drive disassembled, inspected, resealed & pressure tested....
& it MIGHT be OK.....
I'd think about a new or rebuilt drive, IMHO......​

 

[Cheetah 20]

Re: Merc Lower Gear Case Cracked

Well now after reading some other info on this board and doing some research.It appears that some of the reasons for the crack are as follows.

1.Seal on prop shaft is bad
2.Outdrive was stored over winter in the up position
3.Drain hole plugged up (plug was removed and oil drained)
4.New boat owner learning

Options seem to be as follows

1.Change seal ( definite must )
2.JB weld
3. Remove and diassemble lower gearcase and have welded

But where does it end ? In reality if one piece of rubber went bad they were all installed at the same time.Any advise or directions and or opinions would be helpful and appreciated.A good joke would help at this point also.

 

[Bondo]

Re: Merc Lower Gear Case Cracked

At This Point,........

The Drive needs to be Removed,+ Torn Down for Evaluation..........

Your avenues for Repair can Then be analyzed.......

Even if you go for a Welded Repair,.... You need to Empty the case Before it can be sucessfully be Welded......
And, of course,... The Drive will have to be Reassembled to Spec, with New Seals........

Or,............
For $1200./ $1500. you could buy an SEI Aftermarket drive,....... Brand New......

 

[Cheetah 20]

Re: Merc Lower Gear Case Cracked

Thanks for the input.What is the opinions on the SEI outdrive?At this point I have been ,already looking at them.It seems to me I will have more money and time in tearing the outdrive down and reassembly.The dealers around here are backlogged 4 weeks.How hard is it to change the outdrive?Are there special tools needed?

 

[Cheetah 20]

Re: Merc Lower Gear Case Cracked

Thank you for the pressure testing advise.I found out where the water came from.The seal's on the prop shaft are leaking.The JB weld is holding(so far).Now I will change the 2 seals and go from there.Is there any advise on changing the 2 seals?It doesn't appear to be too difficult.

To further explain the water:I stored boat with the outdrive up(now I know better).After lots of snow collected there , it must have froze and broke the seal,seeped in .Then out of no where we got a super cold spell.

So the plan now stands JB weld ,new seals.Try it out,if it doesn't hold.Then new SEI outdrive .Opinions would be appreciated.

 

[Windykid]

Re: Merc Lower Gear Case Cracked

If you go the JB weld way, you need to drill a small hole at each end of the crack. This will prevent the crack from growing.

Hope the JB weld holds for you. Good luck and let us know how it turns out.

 

[thunderroad]

Re: Merc Lower Gear Case Cracked

If they took all the boats off the water that have JB Weld on the lower unit, there would be a WHOLE lot more room for the guys that can afford to drop their boats off at the dealer and have repairs made.