JOHNSON 85hp 1976, Battery hooked up backward. What Smoked?

My Son tells me he hooked up the battery backward and "something smoked under the hood and made a loud hissing sound". After hooking up correctly the motor runs, but has an intermittent weak spark problem causing hard starts when spark is weak. <br /> What would smoke and make a whistling noise when the poles are reversed for about 30 seconds? The motor was not running or cranking when this hapened. I have put new parts on to fix problem, Powerpack, Stator, Rectifier, Coils, Ignition Switch but the problem won't go away.

Re: JOHNSON 85hp 1976, Battery hooked up backward. What Smoked?

Well, if the rectifier has been changed, then check the starter solenoid and starter. Yuo said it wasn't running, but may have smoked when the key was turned to start.<br />When you disconnect the battery with nothing on, does the terminal spark?

Re: JOHNSON 85hp 1976, Battery hooked up backward. What Smoked?

The terminal does not spark, but I am showing 1.5v between the battery past and the cable with it disconnected.

Re: JOHNSON 85hp 1976, Battery hooked up backward. What Smoked?

I found some accessory wiring causing the 1.5v drain. I did remove that problem. I don't have any voltage between the post and cable with key off. Key on is good at 12.7v. with good charge on battery. Motor running is 13.8 to 14v. It's just that hot spark / cold spark thing I can't get rid of. I hooked it up to a homemaid spark tester with all 4 plug wires. They are all the same color spark and all the same intensity, but sometimes hot and loud with a snap, and sometimes small and almost not even visible. Thanks again everyone for the help and what to check, you don't know how much it is appreciated. dj

Re: JOHNSON 85hp 1976, Battery hooked up backward. What Smoked?

Don..... That engine must be turning at 300 rpm in order to generate the proper AC voltage at the stator to energize the powerpack. A weak intermitent electric starter would have an effect on the spark that's generated.<br /><br />With the spark plugs out, the spark at all cylinders should jump a 7/16" gap with a strong blue flame. If (With The S/Plugs Out), you have intermitent spark, I would suspect a faulty ground wire from the powerpack or a poor connection.<br /><br />A quick way to eliminate the instrument and engine wiring harness assemblies, so as to test the engine ignition components alone, is to remove the "Black/Yellow" wire from the powerpack. That wire is the only connection to the ignition kill circuit. You can crank the engine via the battery side of the starter solenoid to the small 3/8" hex nut on the solenoid (not the ground nut). Again.. have the s/plugs removed!<br /><br />Strange that you had to replace so many components as hooking up a battery backwards should have damaged the rectifier only. Keep us informed.

Re: JOHNSON 85hp 1976, Battery hooked up backward. What Smoked?

Thanks Joe, Motor is turning over good with dual battery hook up. I replaced the rectifier first knowing what diodes do when power goes backward. The replacing of the other components is just me searching for the problem and removing 26 year old parts. I removed the stop circuit wire at the powerpack and at the ignition switch to eliminate any internal shorting, no change. I have a remote starter switch I am using at the solenoid. I will replace the powerpack ground wire with a heavier gauge wire today, and route it to a good cleaner ground. Thanks again. dj