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1999 Johnson 50hp surging

T

Tb3625

Member
The first paragraph is everything I've done to the outboard so far and the second paragraph is the latest and greatest problem with it.

My 1999 johnson 50hp model J50PLEEA was not running right so I cleaned and I rebuilt the carbs because they had crap in them, I used a rebuild kit cause the gaskets were ruined when I removed them. There was also a spark jumping around the boot and grounding at the block when it was running, so I replaced both plugs , the wires and boots and it took care of the problem. Tried starting the motor and it idled okay at best. Took it out on the water and it surged at WOT. My friend pumped the primer bulb while running and it stoped surging. So I got rid of the vro pump and converted it to a normal fuel pump, I always premixed anyways. Tried to start it and it wouldn't idle. I opened up the carbs to find little pieces of black rubber from either the old vro pump diaphragms deteriorating or pieces of fuel line. I replaced all the fuel lines and and fuel filter then cleaned out the carbs again. Then I look at the tachometer and it wasn't working. I checked the voltage to my battery while the motor was idleing and my battery voltage didn't change with the motor running. So I then replaced the regulator rectifier. Then the batteries charged fine.

Now today day I go to the lake and ran the motor on and off for 4 hours or so it ran pretty good. Then I go to start it and again it surges. I took a video of it, below is a link to the video, after the initial throttle increase to get going I did not touch the throttle.

https://www.youtube.com/watch?v=jjOUhm703B8&feature=youtu.be


 
Sounds like it has had regular doses of ethanol. This will damage fuel lines and pump components made of rubber composition. Once you get it repaired you need to avoid ethanol blended fuel. All super premium is not non oxy, you have to look at the sticker on the pump. Also if the pump shares the hose with the other fuel choices you should first pump about a gallon in your car or truck.
What color are the plugs and how did you clean the main jets?.....describe the procedure. Thanks, Tim
 
I had a different motor on my boat 2 months ago and that motor ran fine on the same fuel, I have also always used the correct amount of stabil marine fuel stabilizer.
When I cleaned the carbs I tore everything down, took out all the jets. I bought a torch cleaning kit with a bunch of different gage pins and I used those pins to make sure that every single passage was clear in the carbs. I then sprayed carb cleaner on ever part of the carb and made sure that wherever I sprayed it into that it came out somewhere else. I also counted the turns on the screw on the side to make sure I set it back exactly where it was before. After every part of the carbs were clean I bought the factory OMC carb rebuild kits that included the floats. When I adjusted the new floats I made sure that when I turned the carb upside down that the bowl was level. I also blew into the part where the gas line connects to so I could make sure the needle shut off fuel at the correct point, then turned it over to make sure air went through.

I'm not 100% sure, but I don't feel like it's a fuel problem I may be wrong though. After posting this yesterday I took the carbs apart and they were both completely spotless. Also I had my friend try pumping the primer bulb while it was surging on the lake and it had no effect. Could that rule out a fuel problem? It ran great for the first part of the day going from fishing spot to spot and then it started the surging. Is it a possible ignition problem?
 
Do a spark and compression test. If that is a 3 cylinder motor sounds like it is running on 2 cylinders. A 1999 model will have an Ethanol resistant fuel system. That is to easy of an excuse some testing needs to be done.
 
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This is a 2 cylinder motor. I Did a compression and spark test before all the initial work last month, cold it was 125 and 128, warm it was 133 and 135. The spark jumped a half inch gap on both cylinder last time. I'll check spark again today.
 
Surging..........
A gradual up/down increase of rpm/decrease of rpm/repeat = Fuel problem
A quick instantaneous sudden increase of rpm/decrease of rpm/repeat = Ignition problem

You state: "I go to the lake and run ran the motor on and off for 4 hours or so and it ran pretty good. THen I go to start it and again it surges".... then later on you state: "It ran great for the first part of the day going from fishing spot to spot and then it started the surging."

Actually you're making the same statement in different words, indicating........... The engine is running normal, starting from a cold start and continues running normal UNTIL you shut it down. Durning that shutdown period, all of the cooling water drains out of the engine and the heat rises to the upmost portion of the engine where the flywheel surrounds the stator which is the beginning of the ignition and the charging system.

A stator, when it starts to fail, may function perfectly when cool BUT as it heats up, it can and usually does malfunction which results in weak, erratic, and eventually no ignition. It may also cause the tachometer to flutuate. Carefully view that stator to see if there is any portion of it thata might be dripping a sticky looking substance down upon the powerhead area... and if so, replace it regardless of whatever readings you might get out of it.

 
Joereeves what you have said makes sense. There is some white looking grease below the flywheel but it's also on the throttle linkage so it guessing someone went overboard with grease somewhere along the lines. I have a DVA adapter for my multimeter, and I just read the CDI troubleshooting guide after reading your comment. Do I test with the stator disconnected and just plug the leads of the DVA into the stator connectors and crank the motor over to see my readings? Or should I poke holes in the wires to get readings with the motor running at idle and Hooked up to water?
 
Did a spark test today cold, blue spark will jump a half inch gap both top and bottom cylinders. Compression on top cylinder 131, compression bottom 129.
I used my DVA and disconnected all the stator wires. all voltages were in spec according to the cdi electronics troubleshooting guide, I'm fairly sure I did it right, I didn't start the motor I just cranked it over. The resistances were all correct except for one. And that is with the orange/orange black wire. It was supposed to read from 45-55ohms and it read 406ohms. I pulled the flywheel and the stator has nothing leaking out of it. All the magnets look good under the flywheel. The timer base has some of that white stuff on it but it looks exactly like grease and the same stuff is on the throttle linkage.
 
I may have stated at one time or another that I retired in 1991. I don't know if the DVA meters existed at that time or before BUT I have never used one having doing quite well with simply a ohm/volt meter and 30+ years of experience. Bottom line is that I don't know what to tell you pertaining to your readings.

You didn't confirm one way or the other..... the surge, gradual or instantaneous ?
 
NOTE... Forced to make a duplicate message in order to add a bit of info.

I may have stated at one time or another that I retired in 1991. I don't know if the DVA meters existed at that time or before BUT I have never used one having doing quite well with simply a ohm/volt meter and 30+ years of experience. Bottom line is that I don't know what to tell you pertaining to your readings.

The white stuff... probably grease as you mention. The sticky substance is blackish and unmistakeable.

However, that "45-55ohms and it read 406ohms" reading, if you're absolutely sure of it... now, that would concern me.

You didn't confirm one way or the other..... the surge, gradual or instantaneous ?
 
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okay I don't think the stator has anything leaking out of it, it is painted black and just looks and feels like some of the black paint is bubbled. But it's not a sticky substance.
To answer your question I think the surge is more instantaneous, it jumps up and down rpms rather quickly.
Heres a video of the tach when this was happening:
https://m.youtube.com/watch?v=jjOUhm703B8

I completly forgot to add that when this happened I was about 3 miles from the launch ramp and I drove all the way back. If I only kept it at partial throttle it would not surge (if I tried to keep it under 2800 rpms). Again though my friend pumping the primer bulb had no effect on it
 
What spark plugs are recommended for that engine... and are they the ones you're using?

That bubbly appearance of a stator is common and normal. If it were cracked and leaking/dripping, there would be no mistaking it.
 
My watch is water resistant too, but I take it off in the shower. The black debris in the fuel system is likely the remains of what tb has coming off certain fuel system components. Ethanol has caused billions of dollars damage in the marine and small engine industry. VROs have been re-engineered to "resist" alcohol. The marine industry wants us to think everything is okay as manufacturers, dealers, and repair shops line their pockets with cash. I myself have done the same, but educate each customer so it won't happen again.
To address tb's problem I am sure it will show on a timing light while underway. It has to be the trigger. The video shows too fast of an rpm change to be anything else. The trigger may show adequate resistance parameters but under heat, vibration and electromagnetic activity at 3000 rpm.........things change. Good job Joe, DVA is for the younger generation, us old timers can still walk the line with a little knowledge and some educated guesses.
 
Joe and tim, thanks for the advice. Between what you guys have said and the few hours researching this problem online today, I am having trouble narrowing it down between the stator, timer base and power pack. Since theses parts are about $200 each and I don't have the money to just replace each of them, I'm wondering if it's best that I take it to a shop? Unless there is any other troubleshooting I can do. I do not own a timing light
 
I really don't suspect the stator or power pack. The only component that actually moves is the trigger or timing base. The wires are always moving with throttle action. That is my guess. The shop will not do you much better, as intermittent problems can get costly. If its a trigger, I think it will be the cheaper of the 3 components. I have not seen a power pack act as you've demonstrated.
 
My line of thought is with "timguy's" statement. The manner in which your tachometer was jumping around doesn't fall in line with a stator problem. That would lead me into checking the resistance of the timing sensors and the continuity of the timer base wiring.

What plugs are recommended... are they in use... gap setting?
 
I am using the recommended champion spark plugs gapped a .030". I bought them about a month ago so they're pretty new.

I decided to take my boat on a little lake that's closer to me today. The motor ran flawlessly, not a problem from it. I only had an hour or so at the lake, but there were no problems at idle or WOT or anywhere in between. This must mean its temperature sensitive. This boat has a brand new water pump kit installed, not just the impeller and it pumps water like new. Must be something electrical when it heats up after some use.

If I replace the timer base will I have to reset timing on the outboard? I don't have a timing light
 
Disconnect the temp sensor and tape the wires off and see how it runs. You should have S.L.O.W mode on that and it could be malfunctioning. The SLOW system is in the cdi box and can cause crazy running symptoms. Have you done any testing on your ignition at all I am leaning towards a CDI problem. It looks like you have a cylinder trying to kick in.
 
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My alarm was not going off at all though. The alarm works cause it beeps once and lights up once when I turn the key to show the system works. But if it was a faulty sensor wouldn't the light and alarm be on when it was happening?
 
The SLOW should activate the warning system. You should not have to adjust the timing if the trigger/base is a CDI Electronics or OEM unit. I have found that they will match up almost perfectly, just make sure any adjustments are not changed. A timing light can be borrowed from many parts outlets or rented for a meager fee. That way you can check the timing before you start too. You will need a flywheel puller and torque wrench anyway of course. Any electrical component may react to temperature fluctuations and this is more apparent with age and operating conditions over the years. In your case I would suspect that the component at fault moves outside recommended operating parameters at maximum operating temps. There may also be some physical damage to a wire at an active location to the timer base. When I check resistance/DVA on timer bases/triggers, I ALWAYS test at all throttle positions on both a cold and warm motor. Also checking each wire for any continuity to ground. In almost all situations, unless otherwise noted, the trigger needs to be unplugged or disconnected from the powerpack, switchbox, etc.
 
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