1988 120 Johnson Que

[mikey456]

I had trouble last season with getting the motor started. Well, it finally gave out and thru the winter, I diagnosed it as a bad coil. I replaced all of them and the motor came to life. I took it out yesterday and ran offshore. Motor ran great! Even started after sittin with ease. Then, a good day gone bad.
We were running at idle speed and enjoying the evening heading in when the motor just plain shut off. After some Ether and quick diagnostics, it was determined that there was no spark.
Today, I took the flywheel off and tore it down to the pickup. I checked every wire. Visual inspection of the stator passed and the powerpack was spotless. All wiring accounted for. Checked for spark and still none. The Powerpack was installed by me in '07. The stator and pickup are 2 yrs old. Coils new and brand new plugs. Can someone give me some input!! Is it not odd that considering these parts are new or recent, that they could fail so quickly?

 

[ezeke]

Re: 1988 120 Johnson Que

Disconnect the large red plug at the engine and see if it will start by jumping the starter. You may have a short in the kill circuit. Or the ignition switch may be going bad.

You will have to flood the engine to stop it if it starts disconnected.

 

[mikey456]

Response

Response

I appreciate the response! When you say large red wire, the large main plug harness comes to mind. Is this correct? Can you give me specific location of this wire or harness so I know I am doing it right. Tks!!

 

[ezeke]

Re: 1988 120 Johnson Que

Not wire but plug. At the engine, all of the wires in the main engine harness run into it.

 

[mikey456]

Re: 120

Re: 120

Gotcha. I will try one day this week and let you know. I appreciate it.

 

[mikey456]

Re: 1988 120 Johnson

Re: 1988 120 Johnson

I removed the power plug as you illustrated and jumped motor off. Motor didnt start. Checked for spark and there was none so I put everything back. Any other suggestions are appreciated. Tks

 

[ezeke]

Re: 1988 120 Johnson Que

Follow the troubleshooting steps here:
http://cdielectronics.com/downloads...linder 1988-2001 120-140 HP (Quick-Start).pdf

You will need a DVA for your multimeter to perform those tests: http://www.usatoolwarehouse.com/usatoolwarehouse/ESI-640.html

 

[mikey456]

Re: 1988 120 Johnson Que

Thanks for the info.Gonna look at it this weekend.

 

[mikey456]

Re: 1988 120 Johnson Que

I performed the various tests outlined in the troubleshoot you sent me. All is good. Except for the DVA tests. I would like your opinion on the flywheel. To my knowledge, the flywheel is the original.This motor has almost 2000 hours on it. What obvious signs would there be on this flywheel that would indicate it being faulty. I know it has built in magnets. I plan to order the DVA this week as well to perform the other tests. My theory is that the flywheel may be weak and causing the other electrical parts to fail prematurely.

 

[ezeke]

Re: 1988 120 Johnson Que

It's possible that the flywheel sensor magnets have moved. Check them against the chart here: http://cdielectronics.com/downloads/troubleshooting guide/OMC Flywheel Trigger Magnet Location.pdf

 

[mikey456]

Re: 1988 120 Johnson Que

ezeke, I appreciate this diagram. Will check this out. Waiting on the DVA adapter as well. Tks

 

[mikey456]

Re: 1988 120 Johnson Que

Interesting find. I pulled the flywheel yesterday and compared my trigger magnet location to the diagram you sent me. Mine is off by 1/2 inch. Maybe slightly more. But the funny thing is....its been at this position for quite a while. The motor used to run at the current locations. My DVA will be here next week.

 

[ezeke]

Re: 1988 120 Johnson Que

If the magnets are off position, I would look for another flywheel.

 

[mikey456]

Re: 1988 120 Johnson Que

ezeke, I had time to inspect the "built in" magnets of my flywheel today. They are in sets of 2 around the inner perimeter of the flywheel. There are 2 sets that show part of 1 magnet half missing. The third set has all of one of the 2 magnets rubbed off. Whats your opinion of this? Im sure you are going to say flywheel. But I wanna get your final opinion.

 

[ezeke]

Re: 1988 120 Johnson Que

The operation of the ignition system depends on the correct placement of the magnets. Most of us are in agreement that the sensor magnets cannot be repaired reasonably, so the usual alternative is to find a good flywheel.

Faztbullet has been able to locate good used flywheels for others, so you might try a PM to him.

 

[mikey456]

Re: 1988 120 Johnson Que

ezeke, I located a flywheel today. Paid 100 bucks and it looks brand new. The guy was parting out the same motor. All the magnets are intact. I put it on and tried to locate fire in the cylinders. No fire. My DVA wont be here til Wednesday. I have never done this before so I am eager to learn.

 

[mikey456]

Re: 1988 120 Johnson Que

Received the DVA and ready to use it. The directions that came with it are for a Mercury Outboard. I have a multimeter. Could you walk me thru the steps to assemble this DVA to the multimeter? One more question. My tests that I perform per the charts are with the engine cranking over. correct? I appreciate your answers and ready to finally find out what is wrong with this motor.