No spark 76' 85hp Johnson

[Lostfisher]

I am playing with a 85hp johnson It has absolutely no spark on any of the 4 cylinders. The motor is in neutral, I cant seem to find a saftey switch. The guy said that it ran for 15 seconds and turned off. He supposedly tested it for spark after it stopped running and it had a good spark. any ideas on where to start. I havent opened the ignition yet but i have a feeling that something is going on under the flywheel or there is a loose wire.

 

[Joe Reeves]

Re: No spark 76' 85hp Johnson

Remove spark plugs, disconnect RED electrical plug at engine. Crank engine by engaging starter solenoid manually with a jumper wire. Do you now have spark?

 

[Lostfisher]

Re: No spark 76' 85hp Johnson

I gave it a try and there was a quick spark only 1 time and that was it. I took the flywheel off and looked at the stator but quickly became dumbfounded because i had no idea what I was looking at, I am use to the old ignitions and this is pretty much my first time working on a motor with a cdi. This is not my motor and i do have a manual for it. How do i go about testing the ignition. also could the timing have anyting to do with this. It did spark once on the clyinder #1.

 

[boobie]

Re: No spark 76' 85hp Johnson

Two things you'll need is a DVA tester and an open air gap spark tester. Is you manual an OEM manual or some off brand ?

 

[Lostfisher]

Re: No spark 76' 85hp Johnson

I have a spark plug tester that you can adjust the gap with. I also have a multimeter i don't know if it a dva though. what would I have to do in order to check. Also the manual is an OMC manual. Also I tried to play around with it again and I do get spark every once in a blue moon on the 1st cylinder. If the powerpack was bad I would never get any spark right?

 

[boobie]

Re: No spark 76' 85hp Johnson

What you normally use is a peak reading voltmeter to check voltages. You can get DVA adapters for a regular multi-meter that will do the same thing. Some guys on here have built their own. Hopefully somebody will chime in with more info. The power pack may not be bad but there other components in the system that could be.

 

[trimmers]

Re: No spark 76' 85hp Johnson

Start from the basics. I just saved a guy a ton of cash by doing this simple little trick. He had the same issues as yours. Check your battery. Make sure it is full of water and showing more than 12.4 volts. Engines require a good speed when cranking to generate spark through the components. Check your cables at the battery and on the start solenoid and ground on the motor. If your battery shows 12.4V then your ground at motor and positive on solenoid should aswell. His didn't due to corrossion on the neg cable. Check the 4 ignition coils. They need to be properly grounded aswell. His weren't. There was rust at every ground point. Once I got him to clean all that up and with the help of my truck jump-starting his battery, it fired right up. Ran like poop, but fired. 4 new champion plugs later, and he was fishing that afternoon. Basic maintenance first, then trouble shoot wires using the manual. Ensure no one changed the order of wires on terminal blocks and all wires appear to be in good order. If this still fails ya. follow the manual in detail. Good luck

 

[F_R]

Re: No spark 76' 85hp Johnson

Some simple tests:

A physical look at the stuff under the flywheel...anything broken or melted?

Remove the spark plugs and recheck for spark. If it now has spark, either the stator is bad, or it isn't cranking fast enough.

Disconnect the black with yellow stripe wire from the power pack and recheck for spark. Does it have spark now? If so, something is grounding that wire somewhere between there and the key switch. Does it have a kill switch lanyard? Is it attached?

It is possible, but not real likely that you have a bad power pack. Also, bad coil(s) would only kill the spark on the cylinder associated with it.

 

[iwombat]

Re: No spark 76' 85hp Johnson

That model has a big metal plate that all the coils sit on. That plate floats on rubber insulators and is grounded to the powerhead by grounding straps. Make sure the grounding straps on both sides of that plate are in good shape and attached to the powerhead. This is a common failure on the '74-'77 models.

 

[Lostfisher]

Re: No spark 76' 85hp Johnson

I did check under the flywheel and there seems to be no problems everything looks fine underneath. I did unplug the black/yellow striped wire from the powerpack with no luck I also unplugged the sensors along with the black/yellow wire with no luck. I guess tomorrow I will unhook all the grounds and give them a good cleaning in the 30 degree weather yay.

 

[boobie]

Re: No spark 76' 85hp Johnson

I think what you should now do is get your OMC manual and the proper volt meter and check the system voltages out.

 

[Joe Reeves]

Re: No spark 76' 85hp Johnson

Get yourself a cheap $8.95 analog (needle type) volt/ohm meter. Set the meter on the Ohms setting.

Disconnect the Brown & Brown/Yellow wires from the powerpack, then connect the ohm meter between those two wires.

The reading should be 630 ohms +/- 75 ohms.

If the ohm reading is off, replace the stator. If the reading is normal, replace the powerpack.

 

[Lostfisher]

Re: No spark 76' 85hp Johnson

I threw on the ohm meter when i set it to low ohms it was 480 when set to high ohms it read out at 500. Did i need to crank the motor over while testing the ohms? Also should i test the amount of volts that gets put out by the stator?
I would also like to thank everyone for all the help and input on this project.

 

[Joe Reeves]

Re: No spark 76' 85hp Johnson

Do not crank while testing for ohms.

 

[Lostfisher]

Re: No spark 76' 85hp Johnson

I called up a good friend yesterday and he happen to have a powerpack new in the box. I popped it on and i managed to get spark on one side of the motor i believe it was cylinders 1 and 3. So now I am thinking it is either the sensor or both of the coils on the other half of the motor is shot.

 

[Lostfisher]

Re: No spark 76' 85hp Johnson

If i disconnect the sensor from the powerpack would that make a difference in getting spark. Also if i do disconnect the sensor do i have to worry about it damaging the powerpack.

 

[Joe Reeves]

Re: No spark 76' 85hp Johnson

You have four timing sensor leads, one pair fires the starboard bank (cyls 1/3), the other fires the port bank (cyls 2/4).

The two timing sensor leads that ARE firing........ Temporarily move them to the timing sensor location that IS NOT firing. Now, if the non firing coils are now firing, then obviously the coils are okay and so is the powerpack.

In which case, the problem would be with the timing sensor. Check the continuity of the sensor wires and the ohm reading of the sensor itself. Compare that sensor reading with the other one.

I assume you're testing for spark with the spark plugs removed. If not, do so.

 

[Lostfisher]

Re: No spark 76' 85hp Johnson

I swiched the coil wires and both sets of coils spark. So either the powerpack was bad or it is further under the flywheel.

 

[Lostfisher]

Re: No spark 76' 85hp Johnson

I switched the sensors around on the powerpack and the ended up loosing spark so I guess that is it something with the sensors, can they be cleaned or is there a ground or some wireing somewhere that might be bad loose. If i unplug the sensors would I still get spark? I also put the ohms reader on both sets of sensors, they both came out at 2.5 ohms which does not make sense because If one was bad than it woulnt read anything

 

[Joe Reeves]

Re: No spark 76' 85hp Johnson

To prove if you have a bad timing sensor OR a faulty new powerpack, do the following.

Put the sensor wires back on the powerpack so you can determine which bank is firing and thustly determine which timing sensor is firing that back. Mark those timing sensor wires so that things do not become confusing.

Now remove all four timing sensor wires, then connect the good timing sensor wires to the powerpack terminals that were not firing. Check for spark.

If you now have spark on the cylinders that previously didn't fire, the timer base is faulty.

If you still do not have spark on those previously non firing cylinders, that new powerpack is faulty.