cracked gearcase

herbalist_rick

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Jul 3, 2005
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I'm trying to help out a disabled friend who can't afford a new motor. The motor is an Evinrude, 70hp outboard. Model# 70573E. Serial# J0007174. Fits a pontoon boat. The gearcase is cracked from winter freezing, with the crack running a bit over halfway around the cone-shaped area at the front of the gearcase. Total crack length is about 5". Can something like this be brazed, welded, epoxied, etc? Is this worth trying?<br />Thanks<br />Rick
 

denislajoie

Seaman
Joined
May 28, 2005
Messages
62
Re: cracked gearcase

It can be welded but it must be very clean and probably left to a machine\welding shop cause the heat can cause it to warp out of round if not welded right, but definately doable, and cheaper than a new engine for sure
 

herbalist_rick

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Jul 3, 2005
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Re: cracked gearcase

Thanks for the quick reply. Hopefully there's a good welder around here. I'm not a boat mechanic but do have an automotive background. Am I correct in assuming this gearcase is similar in setup to an automotive differential? I'm hoping that I'm not getting in over my head with this.<br />Rick
 

cwx6

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Jul 3, 2005
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Re: cracked gearcase

Hello Rick, <br /> DO yourself a favor and get a Seloc Manual, very easy to understand and it will tell you step by step details and required specialty tools to do the job, I had never worked on a boat motor till last saturday and I disassemble my lower unit all the way down, now for the trick , can he put it back together? Good Luck with your project. <br /><br />CW
 

lark2004

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Jul 12, 2004
Messages
1,080
Re: cracked gearcase

even better than a Seloc (or Clymers etc...) is a factroy manual for that particular engine. There are several places that sell them including I-Boats, Ken Cook....<br /><br />They aren't hard to pull apart and rebuild but You need to be sure that is done properly.<br /><br />As for the gear case crack, Like Denis said, get a machine shop or some where that specializes is welding/fabricating aluminium to weld that up for your friend. If that isn't possible, try looking around an outboard wrecker for another lower unit that you can swap over.<br /><br />Good luck and keep us posted.<br /><br />P.S. WELCOME ABOARD! :D
 

herbalist_rick

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Jul 3, 2005
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Re: cracked gearcase

Thanks, all of you. I very much appreciate it. I've never torn one of these down before so I'm assuming that it's somewhat similar to an automotive differential ring and pinion. I'm a long way from any large marine shops or similar. The nearest place to even get an outboard this size is 75 miles from here so I'll have to check around for a good welder. If I'm looking at that model number right, this motor is from 1973? <br />I'm not sure if this could be a related problem, so I'll ask. Last year, July, she asked me to come over because her boat wouldn't start. What she described sounded like a dead battery or bad connection. What I found was a motor that wouldn't rotate past a certain point. I removed the spark plugs to make it easier to turn by hand and started manually turning it back and forth, managing to get it to turn a little more each time. It felt like there was a soft obstruction in the motor, like a rotton piece of wood. The lake she's on is full of that kind of stuff. Since I'm not familiar with how outboards are set up, I'm assuming it sucked a piece of this debris into the pump, and manually cranking the engine eventually chewed thru it. Am I correct in guessing that this pump is also in the gearcase or do I need to go farther up into the motor to check on this? <br />I appreciate the help and all the patience. If any of you make it over to the computer support forums I work at, I try to return the favor. Thanks.<br />Rick
 

denislajoie

Seaman
Joined
May 28, 2005
Messages
62
Re: cracked gearcase

The pump ia a little higher in the gear case, and is made of ruber so if it did chew in a piece of wood, it might need attention, its pretty close to a ring and piunion except that the pinion has 2 gears on it 1 on either side, so the motor always turns the same way, and the gear that is selected (locked) determines forward or reverse
 

lark2004

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Jul 12, 2004
Messages
1,080
Re: cracked gearcase

Ok, we'll assume that the pumps impeller is no good now, you said you rocked it back and forth. That is a bad thing for these water pumps. The motor should only be turned clockwise. Luckily, you can replace this while the lower unit is off being repaired.<br />The motor was built in 1975, not 73. And you will need to get the manual. If purchaseing one is too hard, try your local library.<br /><br />As a last resort, you can check the evinrude website, or ishopmarine.com for exploded diagrams of the engine. They are seperated into sections, try this link and you will see the one you need first.<br /><br /> http://www.ishopmarine.com/ishop/js...~A0000021~M0011531~M0011543~M0011547~C0143566 <br /><br />Good luck.
 
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