Any ideas on repairing a crack in a lower unit??

[deerhunter53118]

I bought a boat but the lower unit is cracked ,Is there any short term fix it so i can run the boat till winter??<br /> Thanks,<br /> Tim

 

[wilde1j]

Re: Any ideas on repairing a crack in a lower unit??

Depends on where the crack is. If it is causing LU gear oil to leak, probably not. To weld it, generally requires taking all the guts out (the seals would be destroyed by welding heat.) Welding must be heliarc or TIG (I think) for aluminum, If it's a cosmetic fix, something like JB Weld, an epoxy, may work.

 

[taz33911]

Re: Any ideas on repairing a crack in a lower unit??

You can fix it with JB weld but take a dremel or die grinder to the crack to clean it out and give it something to bond to make sure there is no oil in the crack if there is get a degreaser or something it has to be clean to bond good.

 

[deerhunter53118]

Re: Any ideas on repairing a crack in a lower unit??

The crack is on the back of gear housing and yes it is leaking oil.<br /> Thanks,<br /> Tim

 

[deerhunter53118]

Re: Any ideas on repairing a crack in a lower unit??

Thanks Taz,<br />Thats what i heard to?This is just going to be a temp.fix so i can see if there are any engine problems.<br /> Thanks again,<br /> Tim

 

[Mumblerone]

Re: Any ideas on repairing a crack in a lower unit??

Drain the oil; let it drain overnight. Then, as stated above CLEAN, grind, sand, grove the area around the crack (rough up good for epoxy to hold). Be absolutely sure oil is still not leaking: clean with lacquer thinner or other fast drying solvent. Carfully mix the two part epoxy and apply, at leat 1/8" thick or more. Be patient, let it dry. Sand area if needed and paint. Put oil back in. Pray! Always change lower unit oil before winter! Hope this helps.

 

[Capt Ken]

Re: Any ideas on repairing a crack in a lower unit??

You're not going to be able to repair it. If the crack is far enough down the housing to leak, then the crack is past the sealing O ring and you won't be able to patch it with anything. Most of the time, the crack is found in salt water units where corrosion causes pressure between the bearing carrier nut and the housing. When this force gets high enough, it cracks the housing. Its odd that the crack went far enough to get to the O ring. Usually the crack runs forward, then turns up.

 

[dmessy]

Re: Any ideas on repairing a crack in a lower unit??

JB Weld trick doesn't work, I've done the grind ,clean, apply thing and it won't last much more than a couple of hours. Even then , water will seep into the oil. Either replace the housing or weld it.

 

[mnkelsner]

Re: Any ideas on repairing a crack in a lower unit??

Jeb weld has held a freeze crack in the bottom skoag of the gearcase of my 10hp johnxon for more than five years.

 

[slow_boat]

Re: Any ideas on repairing a crack in a lower unit??

There is a marine epoxy that I have seen used to repair a 'grenade' explosion inside the oil filled gearcase parts on lower units. I am talking finger sized holes blown out of the gearcase housing. Can't remember the name of it but it seems as strong as the casting itself. Screen wire mesh was embeded into the epoxy from inside the gear housing where the major holes were and it was just applied thickly to minor holes. It may be that this material works for holes and not cracks but it might be worth a try. It dries a very pale metalic gray color and seems to have metalac properties.

 

[Walker]

Re: Any ideas on repairing a crack in a lower unit??

If its not too big of a crack any good tig man can fix it without melting any seals.

 

[ZAX]

Re: Any ideas on repairing a crack in a lower unit??

AHH new housing?? the one with crack you put that one in the garbage done deal. . . .

 

[gcrandall]

Re: Any ideas on repairing a crack in a lower unit??

I just smacked the front bullet(top) of my lower unit '94 Merc 60 hp on a rock in Canada and it pierced the gear case -causing oil to drip out. <br />I cleaned it out as best I could (the acetone/dremmel idea is right on)put Bondo, GOOP, Marine Silicone and covered all that with - you guessed it - Duct Tape. I ran it like that for 1 week at reduced power settings. Every night I changed oil because it still had a leak that I could not stop and there was a milky look - meaning it had water in it. I either had to not run the motor and lose a week of fishing on my vacation - or limp through it using it very carefully. It worked out well - I wouldn't recommend it to anyone - but I know it will get you through until you can get it fixed right. My prop/skeg welder said it would cost $150-$300 to get mine right ($300 included new skeg which was $150 alone) but said it had 50/50 odds - he would not guarantee it. I had the Merc dealer look it over and had the lower casing replaced/prop shaft/gear assembly - it cost over $1300. IF you are going to try and get a temp patch - make sure it is super-super clean - he said the oil on there sticks into the AL and is the hardest part of the whole deal - he said it must be ground out to get to the good Aluminum or he had no chance of getting a good welding job out of it. JB weld I too have heard will hold under centain conditions/pressures/locations, etc.. The cleaner you get the area the better your chance to even get a temp fix on it. I would not run it WOT either - I would baby it - get up on plane and back off the power/change the oil each day after its used - lots of stress there!<br />My gears were fine after my experience - no rust or anything - but you have to be really careful to keep water and rust out and keep clean oil on it after each use. Good luck to you and get some non-CWD deer der eh? I am looking forward to some North country deer hunting near Minocqua in NE WI this fall. Regards.

 

[icwebpeople]

Re: Any ideas on repairing a crack in a lower unit??

i used jd weld to put a 1 inch piece af my gear case back on my motorcycly as a temp fix to get home after crashing on a trip. its still working 3 years later.<br /><br />just gring a v notch all the wat down the crack and then take 60 or 80 grit sand paper on a sander and rough it up an inch on all sides of the crack. then clean with denatured alcohal. fill v notch first useng popcicle stick let set up 12 hrs then aply a coat over entire crack and roughed up area let set 12 hours fill awith oil and hit the water. if it holds on a high temp bike motor you should have no trouble

 

[seagull369]

Re: Any ideas on repairing a crack in a lower unit??

Drain the oil out of the unit. Locate an EXPERIENCED aluminum welder. Tell him of the situation , including that there was some oil leakage. He will have to take some prepatory steps to clean the affected area. Do NOT attempt to prep the area yourself (including wire brushing or grinding it), cuz you'll probably just end up making his job inevitably that much more difficult. <br /><br />When the guy begins to weld, make sure he back off the job often and allows the unit to cool down. Most alum welders generate LOTS of heat! Enough to do some serious damage to inner seals and other heat sensitive components. There are newer machines out there that do not generate as much heat, but im not sure what therye called offhand.<br /><br />I had a busted skeg welded back on recently so this is how I know all of this. The job only set me back $50. SO go for it. Do not waste your time with these expoxies. They will not hold up!! Esp, in the environment your boat is subjected to.

 

[sho305]

Re: Any ideas on repairing a crack in a lower unit??

Just had a new skeg welded on my old Force for $60 and he supplied the new alumunum. Have it heili-arced(?), it is the only way to do aluminum the right way!<br /><br />Remove and drain the LU, and he put wet rags on it to control the heat if not very close to the seal.<br /><br />Repaired a cracked/frozen one before on a Merc 80hp. Was at the front of the prop shaft and had to have guts removed but stuff was rusted in there anyway and needed repair. About $300 in all for welding and new bearing/seal kit installed by dealer.