blowing fuses

[Riski Business]

I have a 1986 90 hp johnson outboard on my same year boston whaler supersport. At the end of this past summer I swamped the boat by getting caught at the mouth of a river leading out to the ocean on a rough day. The engine did not go under but may have taken some heavy splashing. After retreating to calmer waters, I slowly motored my way to a beach, turned the motor off. I then got the motor going again, left the beach and stopped at another beach where I nudged the sand a little fast and my knee broke the key off in the ignition. When I eventually got to replacing the ignition I found I had blown the fuse in series with my solenoid and ignition circuit. I discovered this because my tilt/trim was not working (previously I did not know they ran thru the same fuse). I am re-wiring all appliances and have ripped out everything except for the ignition circuit and the tilt/trim. All connections are tight and I've brushed them with a wire brush. I have a 20 amp ignition with a 30 amp fuse. The positive feed running from the battery terminal to the solenoid does have a tear in the sheath but I measured resistance with an ohm meter from end to end and only found .2 ohms, and none of the wire strands are torn. I've cleaned it up nice and sealed it with electrical tape. My problem is every time I replace the fuse and turn the key in the ignition the fuse blows instantly, the starter is not engaging the flywheel what so ever. I measured voltage to the solenoid and its getting a full 12.5 V, so is the batter connection at the ignition. I've read it could be the solenoid, maybe some moisture got in during the swamp, how can I be certain? Take it apart?

 

[Silvertip]

Re: blowing fuses

Does the fuse blow when you turn the key to RUN or START? If it blows in the RUN position then there is an issue somewhere other than the starting circuit. If it blows in the START position then the problem can be anywhere between the ignition switch and the engine.

 

[Riski Business]

Re: blowing fuses

Good point, pretty sure it blows in the run position before it even gets to start because I left it in run by accident when I replaced one of the fuses and it blew before I even tried starting the motor. Any ideas?

 

[royal0014]

Re: blowing fuses

Sounds like a dead short, but you knew that. It's possible the knee/key break could have messed up the switch internally. Isolate it and check it out.


<<)))(((>>

 

[Riski Business]

Re: blowing fuses

I've replaced the ignition switch entirely, is it possible water could have soaked into the magneto kill switch and messed something up there?

 

[Silvertip]

Re: blowing fuses

The kill switch, magneto and other ignition related items are not fuse protected nor do they need to be. The instruments on the console, and any other items that are powered via the engine harness (and hence the ignition switch) are suspect. If a 30A fuse is blowing, that is a significant current draw and I suspect you have the big red +12V line in the engine harness connected to the wrong terminal on the ignition switch or that the accessory ("A") terminal on the ignition switch is shorted or misconnected. I suggest you simply disconnect the wire(s) on the "A" terminal on the switch and see what happens. If the fuse no longer blows the problem is in one or more of the accessories powered by that terminal. The problem is not at the engine. If the fuse still blows, double check your wiring on the switch. Here are the meanings and markings on the switch:

B = battery (+12 volts from the engine harness)
C = choke (push to choke feature)
S = Starter solenoid
A = Accessory (powers accessories when key is in RUN)
M = magneto

The only ground on the switch would be one of the "M" terminals. It is entirely possible you have a short between the "M" terminal and the "A" terminal.
M = magneto (yes - there are two of them)

 

[Riski Business]

Re: blowing fuses

The new switch that I've purchased includes an I for ignition and no A so I would assume they are interchangeable. The power from the battery is in fact connected to the proper B terminal. I do not have any accessories in the boat at this point, but I will try disconnecting those wires from the ignition anyway. Are the two M terminals interchangeable? There is also a wire that runs from the kill switch to the harness without going through the switch, I would assume this is ground?

 

[jhebert]

Re: blowing fuses

For good information on typical ignition switch wiring see

http://continuouswave.com/whaler/reference/ignitionSwitch.html

 

[Silvertip]

Re: blowing fuses

I guess my last post got lost along the way. You have the wrong ignition switch. You have a switch for a "battery ignition" (like your car or an I/O powered boat). Those switches do not have the correct internal or external configuration for a two stroke outboard. The "I" terminal on the switch you have supplies power to the ignition system on a battery based ignition system. Your outboard has a magneto system that generates it's own power so the battery isn't needed to run the engine (just don't try it unless you want to pop a rectifier/regulator). Get the right switch and hope and pray you didn't fry your power pack(s).

 

[Riski Business]

Re: blowing fuses

Turns out I had the wiring wrong, thanks for the diagram, I fixed it and the engine cranks without blowing a fuse. The old switch was a 3 way 6 prong switch with A instead of I. The new switch is also 3 way 6 prong and I don't even have anything hooked up to the ignition terminal because I have no accessories in the boat right now, and the engine will crank. You sure the switch is an issue?

 

[Lyle29464]

Re: blowing fuses

some people say the engine cranked and they are trying to say it started.

some say cranked meaning it is turning over.

Does you engine start?

 

[Riski Business]

Re: blowing fuses

It did not start but I did not have gas or water hooked up, I was merely trying to see if it would turn over. She's old and takes a little TLC to get her going and I didn't have the time at the time. I was basically trying to see if I solved the fuse problem, which it appears I did. I was planning on getting her going tomorrow in order to winterize everything but silvers got me second guessing that now.

 

[Lyle29464]

Re: blowing fuses

yes I think he is concerned that your short was caused by hooking your mag ground to a hot terminal on the switch. That would ruin the pack.

 

[Riski Business]

Re: blowing fuses

How can I determine if I've fried the power pack or not?

 

[Lyle29464]

Re: blowing fuses

You can just try to start it. Be sure you have a way to shut it off. If you have wires off the switch you may not be able to shut it off. The key switch grounds the pack when you turn it to off. If it has a manual choke you can kill it that way. Or you can remove a spark plug and use it as a checker. be sure to ground the body of the plug to the engine. Then just attach the plug wire and watch for spark when you turn the engine over. I have a spark checker but you can make one with a spark plug, 2 large clips and a foot of wire.

Have you checked to see if you bought a switch for an outboard? It should have a "M" on the back. If so you should have a black wire with a yellow tracer that goes there. That is what grounds you pack when your shut it off.

 

[Riski Business]

Re: blowing fuses

Oh yea its definitely for an outboard, its got 6 prongs on the back labeled S, I, M, M, C, and B. I just started school at a marine systems program and we just received a similar year 110 hp johnson outboard donation that came with an identical ignition attached. I have the black and yellow wire running thru M and connected to the kill switch which is also grounded to the negative bus bar that runs back to the negative terminal on the battery.

 

[Silvertip]

Re: blowing fuses

"A" stands for "accessory" and "I" stands for "ignition". What are the other terminals labeled. Your engine does not have a battery ignition -- it has a magneto ignition which generates its own power so the battery wouldn't even be needed once the engine is running. The battery is simply used to spin the starter. DO NOT RUN THE ENGINE WITH THE BATTERY REMOVED HOWEVER unless you want to buy a new rectifier/regulator.

So -- what terminal do you have +12 volts connected to?
What do you have connected to the "I" terminal?
What do you have connected to the "M" terminals (if there are two of them). WARNING: Some two stroke switches may have ONE "M" terminal and ONE "I" terminal. If you put +12 volts on the "I" terminal you risk damaging a power pack. On this type of switch the "I" terminal is the same as one of the "M" terminals where two of them were used. This is part of the KILL circuit -- which is part of the power pack -- which does NOT want +12 volts on it -- which can kill the pack.

So is the switch the issue? -- Yes -- but only because you have it wired wrong, and it is still probably wired wrong. The long and short of this is that "I" and "A" are not interchangable.

 

[Riski Business]

Re: blowing fuses

I have nothing wired to the I.
I have 12 volts running to B.
Solenoid is running to S.
I have one M terminal grounded.
I have one M terminal connected to the kill switch.
I have the choke wired to C.

The starter spins counter clockwise but will not lift and engage the flywheel. My battery is very old, could this be an issue?

 

[Lyle29464]

Re: blowing fuses

The starter spins counter clockwise but will not lift and engage the flywheel. My battery is very old, could this be an issue?




Yes. Charge battery and take to store for load test.

The starter is spining correctly. Just not fast enough.