Have to jump starter solenoid for boat to start

[sr54x4]

1988 Formula 242SS with 7.4 Mercruiser (40 hours on rebuild). Boat was sometimes not starting when you turn the key, not even cranking. With the key in the on position, I could jump the two posts on top of the starter solenoid and the boat would fire right up. Started doing it more often so I replaced the solenoid and all was good for a week. Now I need to jump that starter solenoid all the time. When I turn the key, nothing happens at all. With the key in the on position it starts right up when I jump the top two posts on the solenoid (I'm rerferring to the solenoid near the mercathode). With the key in the off position, when you jump it the boat will crank but not fire. Do you think this is a solenoid issue? Or maybe something in the key ignition module on the dash itself?

 

[alldodge]

You need to check the connections on your slave solenoid with a voltmeter. It could be the neutral safety switch, key switch, bad connection or damaged wire. Start at the key switch and see if you get 12V on the Yel/Red wire. If its there, check for 12V on the small terminal with the Yel/Red wire.

 

[Bondo]

Ayuh,.... With a test light, check to see if the key is sendin' power to the slave solenoid's exciter terminal,.....

 

[Bt Doctur]

follow the yellow / red lines

 

[harleyman1975]

This happens to my BOBCAT skid loader if the battery is weak. Make sure that the batt is showing 12.4 volts at rest and does not drop below 11 when cranking. If you have a dead cell it will still be able to crank engine but might not have enough voltage to excite starter solenoid. Do you hear a click when you turn key to start?

 

[sr54x4]

Ok I am going to trace the wiring over the weekend. When its dead and I turn the key, I get no clicks at all.

 

[sr54x4]

Of course everytime I went to trouble shoot this the boat was starting just fine. This weekend it had the problem and the power through the wires. Right now what I have determined is when I have the starting issue there is no power getting to the solenoid. The key switch sends the power but is getting lost somewhere before the solenoid. So I'm thinking this means a broken wire (which probably wouldn't be intermittent??) or a bad neutral safety switch? Where is the neutral safety switch and can they be taken apart and the contacts cleaned?

 

[alldodge]

The neutral safety switch is in the throttle control (item g in pic)

 

[bobkat1864]

Try disconnecting your main engine harness plug. Shoot some contact cleaner in the plug and socket. Inspect it for damage or corrosion and re-connect. Intermittent electrical problems are usually due to bad connections.

 

[sr54x4]

where is the engine harness plug located? under the dash?

 

[bobkat1864]

It's on your engine. A big thick wire harness runs to it, and all or most of the wires from forward go thru that plug. It's round (at least it is on my boat) and mine is about 1.5 inches in diameter. It should have a hose clamp on it too. There will be a red button circuit breaker close to it. Should be on top, starboard side. If anyone has this engine on their boat, please confirm the location of the main harness plug. Thanks.

 

[sr54x4]

It's on your engine. A big thick wire harness runs to it, and all or most of the wires from forward go thru that plug. It's round (at least it is on my boat) and mine is about 1.5 inches in diameter. It should have a hose clamp on it too. There will be a red button circuit breaker close to it. Should be on top, starboard side. If anyone has this engine on their boat, please confirm the location of the main harness plug. Thanks.

went down to the boat tonight and turned the key....nothing. after fiddling with the wires under the dash with no luck, I remembered what you suggested here. I found the plug, and just wiggled it a bit with my hand. Sure enough, the boat started right up. so I shut it down, took the hose clamp off and unplugged the harness. both ends of the plug were very very clean. so, I put it back on and tightened the clamp back up. I'm hoping that maybe it was just loose and my troubles with it are gone, but only time will tell.

 

[alldodge]

Coming out of that plug on the engine side is a large black wire. The wire goes to the engine block ground where the negative battery cable is attached.