77' 140hp johnson- shocking

[D.spencer]

Went out to keystone lake yesterday and weather was good going out but got windy and decided to head in ( not because of wind but fishing sucked). Rough ride/getting sprayed by water coming in as it was whitecapping and I noticed that I was getting "bit" whenever I touched the metal spokes on the steering wheel or the throttle control box ( which in by itself was causing it hazardous to drive). I asked my buddy who was with me to touch the steering wheel to see if I was imagining this ( of course, without asking, he kept touching the steering wheel periodically after that maybee to see if was still there or maybee he liked to get "bit".... I don't know.....) Got back to the ramp and he went to get the truck while I was in the boat putting around. the engine was not wanting to idle good seemed to be missing somewhat and I then noticed something really unusual- when I touched the water ouside the boat, I was getting shocked too! ( I quickly thought that this might be a good way to catch fish but somehow it would be illegal- even if it was an engine malfunction) I thought, "There must be a spark plug wire off or, the ignition is wet and that is what is causing this" . After loading on the trailer and getting out of the water, the first thing I did was pull the engine cover off to see what happened and No plug wire was off nor was the ignition wet. I looked carefully and in amazment as I thought surely that had to be the answer. Not one drop of water around the coil pack or the wires. Anyone experienced this? what was wrong?

 

[emdsapmgr]

Re: 77' 140hp johnson- shocking

It's not unusual to have a lower plug wire come in contact with either of the two rear cowl clamps and short to ground. The difficult thing is that when you pull the hood off, the contact/short is not as apparent. This may by why the engine seemed to be missing.

 

[D.spencer]

Re: 77' 140hp johnson- shocking

Well- I think I finally found the cause of the issue. I did the customary inspection of the ignition wires, etc. Really thinking about it- even a open( circuited) plug wire would cause a miss but the spark would try to find a return path- ground. My thinking would be that a plug wire would at best cause a miss and nothing more as long as there was a ground path for the spark. I tried tracing the plug wires with the engine running holding a grounded (test jumper)wire to see if there was a tiny opening in the insulation -nothing. After much thinking and a second trip out which seemed even worse getting the <crap> knocked out of you, the engine has been faltering/wanting to die/dieing . I finally decided to try something different and started inspecting the grounds with a dvom and a load to tell if there was an issue. The ground at the battery was good as well as the end to the engine block. I then noticed that the coils were on an isolation bracket( for vibration) and the bracket was grounded to the engine block but, by multiple grounds. The grounds were all ok.So, I decided to check the ground from the power pack to the bracket oh-oh trouble in river city! it had a poor ground where the wire from the power pack grounded to the bracket-exactly. The power head had been replaced on this before and someone just *stuffed*the ground from power pack under one edge of it without any star washer and, although the connection was tight and not dirty appearing it was indeed bad. I relocated the ground,cleaned it well, put a star washer on it and re-checked it-now a good ground! My theory is that since the power was not grounded properly that the pack was trying to ground another way which was back thru the ignition feed from the starting controls. As cruel fate would have it, I just fixed this with the intent of going out the next day to check it but instead I got very ill (kidney stone that ran into a host of other complications)and wound up in the hospital instead. I am out now and feeling much better . I will try tomorrow and see if it fixed it and report back.

 

[ksubigbuck]

Re: 77' 140hp johnson- shocking

Dang man...hope you are feeling better. Also hope that your fix does indeed solve the problem.

Hutner

 

[Randybeall]

Re: 77' 140hp johnson- shocking

I have had kidney stones before, I highly recommend you do something else to have fun. Drink plenty of liquids and I hope you never have another.

 

[jonesg]

Re: 77' 140hp johnson- shocking

I had that elec problem, had to put a glove on to touch throttle and steering wheel.

So I put a meter across the throttle controler and steering wheel, voila voltage, the nearest place that can come from is the ignition lock.

Turned out the ignition lock had twisted inside the barrel and was shorting to ground which I provided with resistence.

Twisted the ignition barrel from under the dash and the voltage dropped.

 

[D.spencer]

Re: 77' 140hp johnson- shocking

Update: Runs better, much better. It starts so much better now especially when cold. Doesn't die or cut out and of course, no more shocking ! . Only real (major) issue now is the motor only turns 3,000 rpm WOT and the boat does 38-40 mph( at best) measured with GPS. This is with a 19 pitch prop. Of course, the tach may be wrong but, it seems to be right in the sense that the speed is only 38 mph and should be a lot more. What say ye?

 

[jonesg]

Re: 77' 140hp johnson- shocking

Best place to start is at the beginning, compression and spark test.

 

[ezeke]

Re: 77' 140hp johnson- shocking

I think that your tachometer is off. At 3000 RPM with a 19 pitch prop the highest possible theoretical speed on your motor would be 26.99 MPH.

Make sure that the tachometer is set on 6p if it has settings.

You might consider going to a 17 pitch prop which should put you over 40 at WOT and won't be lugging your engine.