1989 Johnson 48 hp ignition problem

[Les Robb]

This is a continuation of same problem from last July that was never resolved. Over the summer I worked on the motor as time permitted, and finally gave up when I had tried every solution I could think of, except replacing all the components under the fly wheel since I didn't have the correct testing equipment to check them. Week ago broke down and took the boat to a long established dealer near my city and after working on it for a day and a half, their older (experienced) technician admitted he had never seen a problem like this and said he had no solution. He swapped out power pack, flywheel and coil while troubleshooting. They were getting ready to order electronic ignition when I decided to call it a day. Good people only charged me a minimal fee for the amount of hours involved. So question is why firing on one cylinder only and what thought do you have on electronic ignition?

 

[juno pierrat]

have you taken the fly wheel off? On the 48's there are three components under there, charge coil, trigger sensor and stator. Is there a dark gooy discharge under the charge coil? I've gone through two coils in two years on my 87' 48spl, symptons were idled fair to ruff, and started breaking up real bad about 1800 rpm.

 

[Michawilden]

So it has only spark on one cylinder? I guess you have tried the simple stuff: switching coils, switching plugs, disconnecting the kill wire. I owned a 40 hp johnson from 1995 which also showed no spark/intermitted spark on the lower cilinder. After cleaning all ground connections it had good spark for one day but decided to quit. In your case i would look at the ground connections and the connections/wires. Wires can also short to the engine casing. I do not think you got a problem with the powerpack or charge coil. If one cilinder sparks, the charge coils should be good.
Maybe your pick up / trigger coil is faulty. From your story it seems to be the only one that has not been tested.

 

[racerone]

Trigger coil also fires both cylinders.

 

[Faztbullet]

Does yours have the UFI system?

 

[Les Robb]

Flywheel has been off a number of times and was switched out with another in dealers shop. When I first pulled the fly wheel everything looked great and no signs of deterioration oozing or otherwise. Just came home from work and will check wires for poor connections, just used an inline glass enclosed spark tester and the bulb has a very weak and sporadic spark. Going to check again for grounds being good. Coil pack was new back in July. When problem developed.

 

[sutor623]

I just went through an issue with a '96 48hp that was very similar. Was a friends motor. Dealer looked at the motor and slapped a powerpack on it. No change. Ridiculous that they just threw a part at it.

I put the timing light on it and I was dropping spark intermittently on BOTH cylinders at mid-higher rpms, and had a rough idle. According to CDI troubleshooting, dropping spark on BOTH cylinders is usually a bad charge coil under the flywheel. I put my DVA meter on the brown leads and confirmed that this was in fact my issue.

If you have an issue with dropping spark on ONE cylinder, and have changed the ignition coil pack and wires, powerpack, swapped flywheels and still have had no luck, I am almost POSITIVE that it is your timer that is under the flywheel. $50 part. If you had a DVA meter you could check to see if you are getting .5V at the black and white wires to verify if it is a good timer base or not. While you are under there, may as well swap out the charge coil too, as it is only $20-25 and while the flywheel is up, why not change it.

Two other things that you can try. Check the blocking diode by using your multimeter in both directions from the tan lead on the wire harness, to the pin in the red engine connector. I will see if I can find a pic showing you which pin I am talking about. You should have NO resistance in one direction, and read infinite resistance in the other. If you read no resistance or continuity in BOTH directions, you have a bad blocking diode. $12 part. Easy fix.

You can also disconnect the yellow wires from the rectifier and run the motor to see if it clears. If it does you could have a bad stator or rectifier. Ill send you a link to my last thread.

http://forums.iboats.com/forum/engi...outboards/10120842-e48-acting-crazy-any-ideas

 

[Les Robb]

Thanks for the detailed reply, I went out after my last post and before I read yours, and started following the wiring diagram. Pulled the red plug apart and figured I had found the problem. The male lead connected to gray wire pin was pushed in and barely making contact. Gently pulled it out checked continuity and plugged it back together. Now nothing when you turn the key. Plugged it in and out many times with no luck. Beginning to think this engine is possessed and needs a much younger and patient person to work on it. Safety switch ohms out good so I just quit for the evening. Oh by the way I have the complete factory service manual for this motor, I just wish the pins and sockets on red plug were numbered. Would be a lot easier to trouble shoot.

 

[sutor623]

Nah, not posessed, I think you probably blew the fuse when testing the connector. Check the fuse. It is a 20amp blade type, and the fuse harness is right beside the spark plugs. If that doesnt work make sure you have 12v coming in on the yellow/red wire to the starter solenoid while turning the key. Kinda hard to check by yourself unless you have some really long test leads.

 

[Les Robb]

Right on with the fuse, but I live 12 miles out of town and guess I will wait till tomorrow to go in and get a new one. So there is a slim chance that the pin was causing the problem. Will update in the morning. Thanks for all the help and suggestions, and since the motor was running good when the problem occurred I was thinking component failure. Of course she ain't running yet so it could still be that.

 

[Les Robb]

No luck, so now I have another problem that will need attention (that loose pin is a breakdown waiting to happen) and for now totally bummed out. So I am going to pop a natttie and after that take a nap.

 

[sutor623]

No luck, so now I have another problem that will need attention (that loose pin is a breakdown waiting to happen) and for now totally bummed out. So I am going to pop a natttie and after that take a nap.

It can get frustrating, that's for sure. But don't give up that easily man. And I bet that loose pin isnt as big a deal as you are making it sound. Just check continuity to the pin and where it leads to and jiggle it around. If you get continuity put some rubber epoxy in there to hold it together. If that fails, you could look into a new engine wiring harness. Should be $200 or less.

When you say no luck, does that mean that the fuse isn't the cause of the "no start" condition. Go to your manual and look up testing the starting solenoid. It is a really easy test.

 

[Les Robb]

Thanks
Sutor 623, it was the blown fuse and she cranked right up after replacing, but no change in original problem. I did check continuity but my digital meter would show it if it was one strand or the complete wire. Headed for work in the morning for a 3 day shift. Will get back to it next week.

 

[Les Robb]

To close out this post, I had no way to check individual parts so I sat back and started searching the internet. A couple of weeks ago I found a complete under the flywheel assembly that looked like brand new on e-bay for 110.00 freight free. Bought an assembly ring (which I didn't need) settings were perfect snug fit and reinstalled flywheel. Finally after close to a year my little 48 is running on two cylinders again. What I didn't mention was I broke down and took the motor to a dealer and after spending 200.00 for labor they said they still couldn't find the problem.
Thanks again for all the help, and if any one wants to have a shot at the assembly I took off, I'll give it to you and you too can beat your head against the wall.