I rebuilt the carbs, now the 20 Amp fuse is blowing

Hi All,
I just rebuilt the carbs on my 1984 40hp mariner, buttoned it all up and went to start.... nothing. Started trouble shooting and checked the in line fuse it was shot. Replaced - blown instantly.

Things I have already checked:

When I reinstalled the carbs, I had pinched a wire bundle with a red (the wire with the fuse) and a brown. I opened the bundle to check the wires and there is no apparent damage.

The ground from the cranking motor ( I think.. it connects to the engine block behind the carbs is slightly damaged. There are no exposed wires but the metal sheathing over the end of the wire that forms the connector is cracked. Could this be it if so how do I fix?

My questions-
Are there different types of 20 amp fuses? The one that was originally in the boat had a wide wire. The one that I replaced it with had a narrow wire could this be the problem? (I don't think it is but want to check the easy first)

Second is there a protocol for checking for a short? I do not see any apparent wear or damage. What are the possible things that are causing this short? Can any wire in the engine cause it?

Thanks in advance for your help. I am not electrically savvy so I'm sorry if I did not explain things well I can clarify if necessary.

Re: I rebuilt the carbs, now the 20 Amp fuse is blowing

it sounds like you have a short in the line that got pinched. i would ohm test that line. remove power supply and test from one end to the other reading the ohm's. set your meter to ohm and touch the leads on the mter together. this will show you what a good wire should read (it should be 0). next touch the lead to one end of the wire in question and the other lead to the other end. this should also be 0. if it is then move the wire around to make sure. if it changes from 0 to something higher it has a break somewhere. i hope this helps.

Re: I rebuilt the carbs, now the 20 Amp fuse is blowing

Ok - thanks for the response. So I checked the lines that were pinched and the resistance was 0.

Do I go around the engine checking for shorts? Is there a systematic way to do this and are all of the circuits run through this fuse? Could anything in the dash - under the wheel be causing this. My son (3yrs old) was messing around in there while I was working on the carbs.

Also can I pull start this with the blown fuse to check the effectiveness of the carb rebuild??

Any help on this would be greatly appreciated as i would like to get this up and running by the weekend. Thanks again.

Re: I rebuilt the carbs, now the 20 Amp fuse is blowing

On my engine the fused circuit picks up power from the hot post of the starter solenoid and then feeds power back via the fuse to the boat wiring. In this case you would need to check for a ground in that circuit, using the ohm meter. So I guess something in the instrument panel could be causing the ground and therefore blown fuse. Good luck. At least your problem isn't intermittant and should be easier to find. JH

Re: I rebuilt the carbs, now the 20 Amp fuse is blowing

How exactly do I go about looking for a ground in the circuit? Are all of the wires that come out of the starter solenoid part of that circuit? Will the electrical schematics in the Clymer help with this. Sorry with all of the questions but I am really a novice when it comes to electrical stuff and would like to get the boat operational before October, thanks in advance.