1995 Johnson 90hp was Running Rough Now Won't Start

[BrettUmd]

I have a 1995 Johnson 90hp outboord. When I started my engine up this afternoon and it sounded wierd right off the bat. It was low idling and had a bit of a knocking sound... Once I gave it more throttle you could barely hear the knocking, but it would run real rough while it was in gear.

Immediately I thought Ethanol contamination so I replaced the fuel filter (Fram PH 3808), and the spark plugs were a little fouled with oil so I replaced them as well. It started it up just fine, but still sounded rough. Just to elimate any possiblity of a fuel clog, I replaced the inline fuel filter which had some some little bits of pieces in there, but nothing major.

I then tried starting it back up and it would not fire. The gas bulb is full, and when I pump it I can hear the fuel going into the lines. At one point I may have pumped too much fuel because it was coming out the top of the VRO pump from a seal somewhere. That may be something completely unrelated.

I need help figuring out how to get it started, and to determine why it was acting wierd in the first place. I fear the worst, a blown ring or something, but then again it could be a real simple ignition issue. It also ran fine the last time I took it out, so it is kind of frustrating.

Any help would be much appreciated. Thanks

 

[jtexas]

Re: 1995 Johnson 90hp was Running Rough Now Won't Start

Low idling, rough running, it's dropping one or more cylinders. Any particles made it through the filters will be clogging the carbs.
Did all the spark plugs look about the same?
Compression test will tell you about the rings.
Spark test to rule out ignition problem.
Don't forget to charge the battery first.

I'd dump that fuel and start with fresh.
The fuel pump will need repair - you shouldn't be able to make it leak with the primer bulb. But I don't think that would prevent it starting.

 

[BrettUmd]

Re: 1995 Johnson 90hp was Running Rough Now Won't Start

All the spark plugs looked about the same, however one of my friends mentioned that it could be an ignition coil. In theory if an ignition coil were bad, only half the cylinders would be firing, which could explain the rough running and lack of power at idle. It could also explain why it all of a sudden will not start. Does this sound logical?

 

[BrettUmd]

Re: 1995 Johnson 90hp was Running Rough Now Won't Start

I did a spark plug test today and none of the cylinders are getting a spark. I also pulled out all the spark plugs and flashed a light into each cylinder head. None have and indications of damage. One thing I did notice was that my lower unit oil was milky which would explain the rough running in gear. It has been a while since I inspected it outside of water, but the oil was replaced pre-season so there is definately an issue there. In terms of the starting problem, what should I check next and how?

 

[Bobby Autry]

Re: 1995 Johnson 90hp was Running Rough Now Won't Start


Brettumd,

Make sure you kill switch lanyard clip that is connected to the remote control is securely in place . If it is you will not get fire to the spark plugs. It is possible it could have come off a little. I just want to check the small stuff first. Also is your battery fully charged up and have you done a laod test on it to verify if all your cells inside the battery is good. If this is good, I would check/test the power pack and see if it is putting out the voltage. If your motor is like mine, ( 88 horsepower SPL V-4 outboard) you will only have 1 power pack and that could be why it is not firing on all 4 cylinders. Does it crank up when it is cold and does it die on you when it gets hot?

 

[Bobby Autry]

Re: 1995 Johnson 90hp was Running Rough Now Won't Start



Brettumd,

I forgot to add one more thing I just realized that you had water in your lower leg unit that could be a factor in the knocking noise when you throttle up. When you took out your saprk plugs did you try to turn the flywheel by hand that will tell you if you have something binding up in the power head or maybe the lower leg unit because of the water. If you do have a bind or is hard to turn I would pull the lower leg unit off and turn the flywheel again if it turns easily then your lower leg unit is the cause if your flywheel still turns like it is bind up then you have a problem in your power head. Let me know what you fin I am curious. Good luck to you and hope it something easy to fix but if not we will help you out on this forum. Make sure to get a manual for your specific motor, I got one and it has saved me alot of money so far. I haven't had to take it to the shop yet to get things fixed.

 

[jtexas]

Re: 1995 Johnson 90hp was Running Rough Now Won't Start

Right, make sure the battery is good and fully charged...a run-down battery might not deliver enough cranking rpms to produce spark.

Rule out the kill circuit by disconnecting the black/yellow wire from the powerpack, and retest. If the engine starts you'll have to choke it to shut it off. Alternatively you could unplug the main harness and jump the starter solenoid to crank it. Best have the plugs out and grounded, don't want it to start like that.

Still no spark you'll have to test the stator, powerpack and coils, here's a step-by-step:
http://rapair.com/Portals/0/downloads/TroubleshootingGuide.pdf

Your friend could be right, is why I suggested a spark test to rule that out. A compression test is also a good idea, no sense pouring money into a machine with bad compression it'll never run right. If you got compression and spark then you focus on fuel.

When you drained the gearcase did you notice any metal in the oil? Small amount of shavings on the magnet is normal but splinters or chunks is bad news.

Have you got a manual?

 

[BrettUmd]

Re: 1995 Johnson 90hp was Running Rough Now Won't Start

Just got back from the marina... the boat is now fixed. There were two factors which lead to my issue. #1. The ground wire to the power pack was slightly corroded. #2. One of the plugs coming out of the power pack was not securely plugged in. This plug had a whole bunch of green wires coming out of it.

Once I fixed both those issues, it fired right up. I also replaced the washers on the lower unit screws to eliminate that as a possiblity of my leak. That is a whole other topic for another day though.

Thanks everyone!