1973 85 horse johnson ignition

[catfish1288]

I hit my key and I get nothing. not even a whisper. it has a new switch. I know my starter and selanoid are ok. I see the neutral safety switch and I only see one wire coming off it. the bottom one. also I see a wire that is close to my starter that has a fuse in it. will the fuse cause it not to start. how do I cross the solenoid to try and start. please help. I am going nuts

 

[Joe Reeves]

Re: 1973 85 horse johnson ignition

The 20 ampere power fuse is in one of the smaller red wires leading from the starter solenoid. If blown, replace it. Many boaters blow that fuse when in the process of working on their ignition switch.

When turning the ignition switch to the start position, 12 volts flows down the small white wire to one of the small 3/8" nut terminals of the starter solenoid... then the voltage flows from the other 3/8" nut terminal to the safety switch ground. If voltages are present, perhaps the switch needs a slight adjustment.

To jump the solenoid... use a small jumper from the battery cable large terminal of the starter solenoid to the small white wire 3/8" nut terminal. That'll engage the solenoid to crank the starter.

 

[catfish1288]

Re: 1973 85 horse johnson ignition

hey thanks. I will do that. can I bypass the fuse? completely eliminate it? how do I bypass the neutral safety switch?

 

[Joe Reeves]

Re: 1973 85 horse johnson ignition

Do not "EVER" attempt to bypass either one of those items unless you have some weird desire to see that rig burn to the ground!

Either repair it properly or give it to someone that will.

 

[catfish1288]

Re: 1973 85 horse johnson ignition

I would never run it without the proper safety switches and fuses being in their proper place and functional. I am just trying to get the thing to fire. it has new stater and I crossed the starter to make it turnover. I put a new fuse in it. it still wont fire. what else should I check? it also turns over really slow with the plugs in but when I take them out it turns over like it should. we have checked the compression and it checked in the low 130's on all cylinders

 

[Joe Reeves]

Re: 1973 85 horse johnson ignition

It appears like you're now saying that the engine is cranking over via the ignition switch.

Note that "cranking" pertains to the engine turning over/rotating, the flywheel is revolving. Fire pertains to the ignition, proper spark at the spark plug area.

For test purposes, you can temporarily use a small jumper wire to ground out the 3/8" nut terminal at the starter solenoid to eliminate the safety switch... the wire that leads to the safety switch.

The engine must crank over at least 300 rpm for the stator to energize the powerpack, needed in order to have proper spark. A slow cranking engine will have weak, erratic, or no ignition/spark.

When a engine cranks over slowly, it is due to one or more of the following....................

Bad battery... Bad starter... Good battery but needs charging... poor connection of a cable or wire in the starter system...

To test the starter... run good known jumper cables directly from a good known fully charged battery to the starter. If the atarter cranks the engine over fast, then obviously the starter is okay... and the reason for the slow cranking is elsewhere.

Best to remove all cables and wires pertaining to the starting system, including the black ground wire at the powerhead and also the actual battery terminals at the battery. Clean thoroughly all of the end terminals of the cables/wires and also the components to which they attach. Then tighten them with a wrench or pliers... not your fingers if wing nuts are being used.

 

[catfish1288]

Re: 1973 85 horse johnson ignition

thanks a lot. first thing in the morning I will be out there disconnecting every wire one at a time and do some cleaning. I do have one more question. will a bad wire at the key switch cause it not to fire?. I know I sound like an idiot with these crazy questions but I have never had this much trouble with a motor before. thanks for the help

 

[Joe Reeves]

Re: 1973 85 horse johnson ignition

The ignition of that engine is self contained, meaning that it would start even if nothing was hooked up to it. It does not depend on battery voltage being applied... if battery voltage is applied to that ignition system, it will most likely destroy the ignition components.

A bad wire at the ignition switch would interfere with the fire/spark IF.........

1 - A wire at the switch is applying battery voltage to the Black/Yellow (kill circuit) wire that leads to the powerpack.

2 - A wire is somehow shorting out that Black/Yellow wire.