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1978 70 hp johnson will not start or crank over

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kl50bucks

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I am new to this forum and was told this is the place to find answers, so here I go. I took my boat out last weekend and she fired up just like she does every time. When I got to my favorite cove, I trolled around a bit, then decided to head up river. When I went to turn the key, there was no sound at all. After several attemps to start ol' betsy, I found some good sameritans who were kind enough to tow me in. This is what I've done so far. I checked my fuse at the engine and found it to be good. I replaced the solenoid,ignition switch,starter and ignition coils, most of which were being relaced anyway because of age. I am getting 12v at the solenoid and starter, I checked my battery cables and found no corrosion. I checked my grounded areas and they appear to be good grounds. Can anyone offer any suggestions?
 
On many older engines, the neutral safety switch inside the control box becomes slightly out of adjustment. When this happens, the electric starter/solenoid will not engage... a safety feature to prevent one from accidently starting a engine while in gear when working properly.

Jiggling the throttle/shift lever is usually a telltale action as this normally causes the neutral safety switch to make contact.

If this is the case, simply find the neutral safety switch inside the control box (plastic thing with two white wires leading to it), loosen the retaining screws slightly and shove it closer to the cam that actuates it.
 
Thanks for all the replies. I ran a jumper to the starter and it engaged the flywheel. I double checked all my wires for corrosion and dead shorts. Last night I took my volt meter and tested the solenoid to see if power was going to the starter and its not. (Please keep in mind that ol betsy has ran many times before this incident). Just for laughs, I tested the negative lead on the solenoid and found 12v (how is this possible?) Did I screw something up? I troubleshot my wires back to the ignition switch and they are correct to my knowledge. Any thoughts?
 
When i turn the key on, power is supplied everywhere except the starter. I got a new solenoid and got the same results. When i run a jumper from the battery side to the starter side, the motor runs fine. Thoughts?
 
Run a small jumper wire from the large battery terminal of the starter solenoid to the white wire that is attached to one of the small 3/8" nut terminals of the starter solenoid.

If that DOES NOT cause the starter to engage... the black wire on the remaining 3/8" nut solenoid terminal IS NOT grounded.

If however, the starter DOES ENGAGE... see post reply #3.
 
As soon as I get home, I will check on it. Also, when I bought the boat, the key ignition is in the dash and not part of the control housing. The only connctions in the control box are the throttle cables.
 
kl50bucks said:
As soon as I get home, I will check on it. Also, when I bought the boat, the key ignition is in the dash and not part of the control housing. The only connctions in the control box are the throttle cables.
Click to expand...

There needs to be a neutral safety switch on that rig somewhere, otherwise it would be possible to start the engine in gear at full throttle (not a good idea).

The older engines had the black ground wire leading from the starter 3/8" nut solenoid to a neutral safety switch on the powerhead which would only ground out when the throttle was retarded.
 
Please understand that this motor was running perfectly til my last outing. The starting system is very simple I agree. I have checked and double checked the wiring and it is as it should be. The solenoid does not make a clicking sound.
 
Hey joereeves, I took a jumper from the battery side of the solenoid to the white wire 3/8 nut on the solenoid and got nothing. You said that by doing this, I should have fire but I don't. You said that it might not be grounded, even though this ground wire has always been there without incident, I changed the location of the ground and now I ol betsy is happy once again. I had a grounding issue. Thanks to all of he replies on this forum. All of you have AAA+++ in my book. Thank all of you.
 
if you see 12v on the negative side of the solenoid pick then you have no ground for whatever reason...go back and read joe reeves entry...when you turn the key to the start position you should read the +12 volts on one side of the solenoid pick and ground on the other...the complete 12 volts should be dropped across the solenoid..what you are seeing when you see +12v on the negative side is a feed thru of the 12v thru the solenoid with no drop because you are not pulling current...with the engine just setting out of gear and ready to start you should read zero ohms or damn close to it from the negative side of the solenoid to frame ground... also from the same terminal on the solenoid to battery negative should be zero ohms..
 
dont just add a ground wire....find out what is wrong with original wiring and fix it...for safety reasons...
 
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