connected battery posts with wrench...

Marley88

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Joined
Mar 4, 2014
Messages
17
Just replaced the battery on my boat and, while tightening down the nuts, made the mistake of bumping my wrench into the other terminal, connecting both posts with everything hooked up. Sparks flew and now the motor won't crank and the tilt and trim won't work, but all the other electronics still function just fine. Tried a different battery, same results. The battery switch is the first thing in the circuit so I tried bypassing that only to have the same results again. Beyond that, I'm not sure what else could have blown. It's a 16 ft StarCraft with an '86 tohatsu m50c so parts aren't easy to find anymore. I'm not sure if it could have blown something in the motor, the starter, or hopefully just a cheap fuse. I'm fairly handy with a wrench, but not so much with electrical stuff so I don't really know where to go from here. Any advice would be greatly appreciated! Thanks!
 

lmuss53

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Sep 9, 2008
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1,227
There is usually a big master fuse somewhere, Follow the hot wire from the battery to the starter and look for a fuse holder on one of the wires branching off of there. On my OMC motors it is in a rubber sleeve, it is also red I'm pretty sure.



Here's a picture of my 70 Johnson, the fuse is on the red wire in the black sleeve to the right in the picture. You should have something similar under your hood.
 
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Grandad

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Jun 7, 2011
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1,504
A momentary shorting of the battery terminals doesn't usually do damage to anything other than your underwear. Assuming the battery is connected with correct polarity and since the small accessories still work, I'd suspect that the batteries aren't/weren't fully charged and can't handle starting loads. - Grandad
 

Marley88

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Joined
Mar 4, 2014
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17
Found what seems to be the same fuse as in the picture and it is clearly blown. Nearest auto part store didn't have the exact one so as soon as I can find it, I'll pop it in and see if she cranks! Thanks!
 

Marley88

Cadet
Joined
Mar 4, 2014
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17
Also, can anyone actually read the size of fuse in that wiring diagram? It looks like it says 20A but its pretty blurry any tough to make out. The blown fuse I pulled out was 35A. Would definitely prefer to put the correct one back in.
 

Marley88

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Mar 4, 2014
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Thanks! I actually just found a parts catalog that also said 20A so that's solved. That PDF was just showing up really blurry on my tablet making everything difficult to read. Not good to know that the previous owner would just throw a random larger fuse in, hopefully that's the only thing that blew.
 

bruceb58

Supreme Mariner
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Mar 5, 2006
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30,620
Sure you didn't connect the battery backwards? That fuse should not have blown with what you did.
 

tav

Petty Officer 1st Class
Joined
Feb 8, 2008
Messages
239
had a similar problem and nothing worked until someone told me look for that master
fuse .....mine was 20A I think. yup it was blown, replaced it a good to go. it might be that.
 

lmuss53

Lieutenant Junior Grade
Joined
Sep 9, 2008
Messages
1,227
I have seen that quick dead short blow that fuse on several occasions. I also know that the power to engage the starter and operate the tilt and trim flows through that fuse, it is an obvious place to check.
 
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