Help! First time poster! First time boat owner! Johnson 75hp fuse blows immediately!

[BryantDennyKennedy]

I recently purchased a 71' model Glastron with a 1976 75 hp Johnson outboard engine. When I bought it the guy said it had an ignition problem. I thought it was the solenoid so I replaced it. That wasn't the problem. I can have the switch turned to the off position and the fuse will not blow. As soon as I turn the switch to the on position, the fuse blows immediately. I have a new battery, so the terminals are clean and corrosion free. I have looked for any signs of the wires being faulty as well as corrosion and cannot find anything wrong. I can make me a jumper wire and touch the hot side of the solenoid, (with the key in the off position), to the hot leg of the starter and it will turn over with out blowing the fuse. So I am figuring it has to be before the solenoid. (ex. wiring harness coming from controls or ignition switch) What is a good process of elimination and how do you test these items. I need to find the problem because I am anxious to get it into the water. Someone please advise, it would be greatly appreciated. I am mechanically inclined but I just do not know which way to go. At wits end in Alabama!

 

[Lyle29464]

Re: Help! First time poster! First time boat owner! Johnson 75hp fuse blows immediate

First thing to my mind is Did you get the correct part from a marine dealer or pick up a solenoid at a auto parts store? The auto parts will not work with out a few changes. Number 2. The key switch does not supply 12 volts It ungrounded the pack when you turn it to on. Your volt oms meter will tell you what is wrong.

 

[BryantDennyKennedy]

Re: Help! First time poster! First time boat owner! Johnson 75hp fuse blows immediate

Yes, I got the solenoid from a marine dealer. I have a ohm meter but I don't know which wires to test. Do I test it at the ignition inside the control box or on top of the the engine where it meets the solenoid? Also, the choke solenoid doesn't work. It cranks and runs great if you pull start it or jump the solenoid with the key off or the key on with the battery disconnected. It is a red connector wiring harness. Please advise.

 

[jonesg]

Re: Help! First time poster! First time boat owner! Johnson 75hp fuse blows immediate

remove the controler wiring, apply low volts to any particular wire color and check at the other end, shucks I'd just buy a new wire loom but if you feel like tracing wires..if your meter has a battery in it just check for continuity.

also remove ignition switch and look for shorts in the wire terminals on the back, its not too rare that they go bad either.

Mine was loose in the dash mounting bezel, it twisted and started shorting out when the key was turned, just another thing to look for.

 

[seahorse5]

Re: Help! First time poster! First time boat owner! Johnson 75hp fuse blows immediate

I As soon as I turn the switch to the on position, the fuse blows immediately.

Disconnect the electric choke wires. The choke solenoid commonly shorted out on those models.

If not, check under the dash or in your control box for a wiring problem or for any shorted gauges.

 

[F_R]

Re: Help! First time poster! First time boat owner! Johnson 75hp fuse blows immediate

I can have the switch turned to the off position and the fuse will not blow. As soon as I turn the switch to the on position, the fuse blows immediately. !

I wish I had the wiring diagram for that one, but I don't. So, I have to ask you, are there two wires or one going to the choke solenoid (in addition to ground). I think one, so my answer is based on that.

As far as I know, when you turn the key on voltage is sent to the hot horn and choke switch. Plus the tachometer or anything else you might have connected to it. So, the fault lies in one of those items, or the wires going to them. There are two approaches to finding it--either at the control end or the engine end. One way is to disconnect the purple wires from the key switch, then re-connect them one at a time and see which blows the fuse when you turn the key on. Then you know which circuit to check for the fault.

 

[BryantDennyKennedy]

Re: Help! First time poster! First time boat owner! Johnson 75hp fuse blows immediate

OK. I checked the choke solenoid wire (there is only one and it is purple) by disconnecting it from the bus terminal and turned the swich on. The fuse blew. Then I disconnected the purple wires on the back side of the ignition switch and then tried to turn it over into the on position. The fuse blew. Any suggestions. I want to buy a new harness but I don't know if it is the engine side, or the control side. It could be a grounded wire. A bad ignition switch. A choke solenoid. Or one of the two wiring harnesses. Where should I start. I am on a budget and really don't want to have to troubleshoot $600.00 worth of stuff. Please advise.

 

[billy4hp]

Re: Help! First time poster! First time boat owner! Johnson 75hp fuse blows immediate

OK. I checked the choke solenoid wire (there is only one and it is purple) by disconnecting it from the bus terminal and turned the swich on. The fuse blew. Then I disconnected the purple wires on the back side of the ignition switch and then tried to turn it over into the on position. The fuse blew. Any suggestions. I want to buy a new harness but I don't know if it is the engine side, or the control side. It could be a grounded wire. A bad ignition switch. A choke solenoid. Or one of the two wiring harnesses. Where should I start. I am on a budget and really don't want to have to troubleshoot $600.00 worth of stuff. Please advise.

If your blowing a fuse then it's simply a short.... In the automotive repair world we remove the fuse and use a high ohm bulb in place of the fuse (cheapie hand held spot lights work great).... Turn on the circuit and the bulb will light up, then start unplugging circuits until the bulb goes out.... When the bulb goes out you have found the circuit that is shorted, from there find out what's at fault (shorted wire, faulty component, etc)....

Good luck....

 

[BryantDennyKennedy]

Re: Help! First time poster! First time boat owner! Johnson 75hp fuse blows immediate

Well with a collaborated effort I was able to figure out the problem. The guy I purchased the boat from apparently didn't have any idea what was wrong with the ignition system so I began to trace what it could be. I started at the solenoid and replaced that. Then I cleaned all of the connections with a wire brush to make sure they were corrosion free. (still blowing fuses) Then took the ignition switch out and went to replace that when I noticed from a wiring diagram that the ignition switch was wired wrong. This guy had the solenoid wire going into the choke position on the back of the ignition switch and 3 other wires crossed up somehow when he was trying to fix the problem. I straighted out the wiring on the back of the ignition and presto....Cranks like a charm and it blows no more fuses. Thanks for all of the help and ideas.

 

[jonesg]

Re: Help! First time poster! First time boat owner! Johnson 75hp fuse blows immediate

If your blowing a fuse then it's simply a short.... In the automotive repair world we remove the fuse and use a high ohm bulb in place of the fuse (cheapie hand held spot lights work great).... Turn on the circuit and the bulb will light up, then start unplugging circuits until the bulb goes out.... When the bulb goes out you have found the circuit that is shorted, from there find out what's at fault (shorted wire, faulty component, etc)....

Good luck....

Now thats a neat idea, I was thinking to use the radio.