How can I jump a 35hp Johnson?

[steviecops]

Hi<br />I have a friends 1977 Johnson 35hp, electric start motor that I'm trying to get going for him. He said it "just stopped working"! I've done the resistance tests on the charge and sensor coils, but want to do the output tests on the charge and sensor coils, and the powerpack. The ignition coils are going to be replaced anyway as they look in a very bad way.<br /><br />What is the best way to jump the engine from a battery so that it cranks over? I've thought of just attaching the jump leads direct to the starter motor or selonoid, but want to make sure I won't damage anything before doing so.<br /><br />Thanks in advance.<br />Steve

 

[Silvertip]

Re: How can I jump a 35hp Johnson?

The safest way is simply connect the jumper cables from the battery you intend to use to the cables from the engine. If those are missing, connect the negative jumper cable to a good (unpainted) ground point on the engine block. Connect the positive jumber cable to the large post on the starter solenoid (not the one that feeds the starter). If the ignition circuit is not functional, to start the engine, jumper battery plus to the small ignition switch terminal on the solenoid.

 

[R.Johnson]

Re: How can I jump a 35hp Johnson?

You can do it that way. The trouble being that most jumper cable clamps are big, and clumsy for working around an outboard. I saved a set of battery cables from a junked engine for this use.

 

[steviecops]

Re: How can I jump a 35hp Johnson?

The wiring loom is there, but there isn't an ignition switch. There are 5 wires that should be attached to the switch. Red/purple, Yellow/red, Black/yellow, Purple/white and Black. If I touch the right two wires together, would that crank the engine? Which are the right two wires?<br /><br />Thanks<br />Steve

 

[steviecops]

Re: How can I jump a 35hp Johnson?

Hi<br />Any ideas about which wires to cross?<br /><br />Thanks<br />Steve

 

[Paul Moir]

Re: How can I jump a 35hp Johnson?

Steviecops - here are the BIA wire colour codes:<br /><br />Black - All Grounds<br />Black with Yellow stripe - Magneto Short with ground (black) to kill engine<br />Gray - Tachometer signal<br />Yellow with Black stripe - Choke<br />Red - Unfused +12v from battery<br />Red with Purple stripe - Fused +12v from battery<br />Purple - +12v from ignition switch for accessories<br />Tan - Overheat sensor to warning horn<br />Pink - Sending unit to fuel gauge<br />Yellow with Red stripe - Ignition switch to starter solenoid<br />Yellow - charging stator to rectifier<br />Lt.Blue with White stripe - Trim up<br />Green with White stripe - Trim down<br /><br />So, if you connect the Yellow/Red to the Red/Purple, the engine should crank and start. If you touch the Black/Yellow to the Black wire you'll kill spark and the engine will stop. Never, ever let the black/yellow wire touch anything else. <br />The wire that doesn't match up (Purple/white) is for the choke. Connect it to the Red/Purple wire and the choke plate should close.<br /><br />Clear as mud?? <br /><br />PS - for when you get your ignition switch:<br />B - Red/Purple<br />A - +12v to Accessories when key is 'on'<br />C - Purple/White<br />S - Yellow/Red<br />M - Black/Yellow<br />M - Black

 

[steviecops]

Re: How can I jump a 35hp Johnson?

Thanks Paul, that's great.<br /><br />All the best<br />Steve