1996 50hp Johnson No SPARK Top Cylinder

[woodtick007]

I have a 1996 2 cylinder 2stroke 50hp motor that is not making full power. The VRO system has been replaced with the older style fuel pump. The engine had been stored for about 3-4 years and I just rebuilt the carbs along with removing the VRO. I set the carb setting to 3.5 turns and went to the lake to test the motor. Initially the motor would not make more than 2000-2400 rpm at WOT in a 16ft Lowe fishing boat. After while of adjusting the carb jet in and out the motor ran like it should with excellent power, and RPM's of 5200-5400. After running the boat for about 20 minutes I was satisfied that the engine would start at the click of the key, idle excellent, hold steady rpms at various throttle setting and run strong....I loaded it on the trailer and went home happy. This morning I took the boat out to the river to do some Walleye fishing and the engine started with the click of the key.... but would only make 2000-2400 RPMs . I took the cover off and replaced the spark plugs thinking one may have fouled but the problem remained. Can someone please offer me some input on this. Thank You so much. Greg

 

[o/b tech]

Re: 1996 50hp Johnson No Power

Re: 1996 50hp Johnson No Power

What colour was the burn on the plugs when you replaced them and check to make sure that both throttle plates are opening when the throttle is advanced. Take the airbox cover off and check the throttle plate movement when the mottor is not running.

 

[woodtick007]

Re: 1996 50hp Johnson No Power

Re: 1996 50hp Johnson No Power

Both are opening fully.... The plus were black. Today when I removed the plugs they had no color at all.... well maybe a little tinge of black.

Could this be some type of ignition problem where I am having a cylinder not fire?

 

[o/b tech]

Re: 1996 50hp Johnson No Power

Re: 1996 50hp Johnson No Power

If both plugs are the same colour than the ignition system is probably fine. When you did the carb rebuild did you check the float height. The float should be parallel with the carb body when it is upside down and the float bowl is removed.

 

[woodtick007]

Re: 1996 50hp Johnson No Power

Re: 1996 50hp Johnson No Power

That is exactly how I set the float level.....Parallel with the bottom of the carb body. Could a grounding problem cause an ignition problem? When I first started running the engine after it was sitting for 4 years the tach did not work and the engine would stop when trimmed all the way down. Then the tach started working and the engine would run when trimmed down.

What is the easiest way to test for spark? What would have made it run so well and then stop running well??

 

[tashasdaddy]

Re: 1996 50hp Johnson No Power

Re: 1996 50hp Johnson No Power

did you use rebuild kits on the carbs? did you remove the high speed jet and clean it?
Have you read this? http://forums.iboats.com/showthread.php?t=299680

did you check compression and spark, could have a coil failing, running on one cylinder, or one carb failing, which is worse as it is not lubing the cylinder.

 

[5150abf]

Re: 1996 50hp Johnson No Power

Re: 1996 50hp Johnson No Power

Main jets, bottom of float bowl, that is exactly what the motor does when they are dirty.

Pull them and run a copper wire through them a couple times and that should take care of your problem.

I am curious as to what exactly you turned 3 1/2 out, that motor has non adjutable jets so there shouldn't be anything to turn, you may have just loosened the jet.

The mid jet is under a cover screw at the top front of the carb, if it was that you need to tighten it.

I have an '81 50 which is basicly the same engine.

 

[tashasdaddy]

Re: 1996 50hp Johnson No Power

Re: 1996 50hp Johnson No Power

5150abf is correct unless you have newer carbs than 1996. 1996 had fixed jets. up just seat them, no adjustment.

what is the model # of your motor. lets verify what you have.

 

[woodtick007]

Re: 1996 50hp Johnson No Power

Re: 1996 50hp Johnson No Power

There is a needle valve on the top right side of the carb perhaps "jet" is the wrong word... Sorry about that. The dealer told me that the setting was/is 3.5 turns out and to make adjustment in 1/8 turns. What does the needle valve affect?

I installed new kits and pulled the jet from the bottom while having the carbs apart. The carbs were not gummed up from bad fuel.... they were full of injector oil as a result of them having not fuel and creating a vacuum on the oil tank. What to took them apart they looked "clean"...

 

[tashasdaddy]

Re: 1996 50hp Johnson No Power

Re: 1996 50hp Johnson No Power

again i am going to ask? "what is the model # of your motor. lets verify what you have." it looks like a 1997 or newer. they do have the idle air mixture adjustment on starboard side of the carb. it effects the fuel to air ratio, too much air, is lean, to much fuel is rich.

 

[woodtick007]

Re: 1996 50hp Johnson No Power

Re: 1996 50hp Johnson No Power

J50tleds

 

[tashasdaddy]

Re: 1996 50hp Johnson No Power

Re: 1996 50hp Johnson No Power

you are correct it is a late model 1996 with the newer carb. but the adjustment only effects the idle circuit. i would suggest checking for a clogged high speed jet, bottom of the bowl, stuff settles their, and gets into the jet. if that does not solve it, link n sinc.

 

[woodtick007]

Re: 1996 50hp Johnson No Power

Re: 1996 50hp Johnson No Power

what size wire do you suggest I use to push thru the jet to "unclog" it...I Please let me know either guage wire or thickness in thousands of inches.

If the jet is clogged How can you explain the motor running fine for 20-30 minutes? When I soaked the carbs before reassembly they were spotless and then I sprayed carb cleaner thru every thing followed by blowing them out with compressed air.

 

[woodtick007]

Re: 1996 50hp Johnson No Power

Re: 1996 50hp Johnson No Power

I just checked the spark.....and the top cylinder is not firing... Its a one piece coil for both cylinders. Can one half the coil be bad? Or do I have other issues to check before replacing the coil? What about an aftermarket coil? I would like to fish today but no Evinrude dealers are open on Sunday in my area of Michigan.

 

[o/b tech]

Re: 1996 50hp Johnson No SPARK Top Cylinder

Generaly the ignition coils either work or they don't. Check to make sure that the spark plug leads look in good shape. If you were checking spark by using the spark plugs make sure they are not giving you a false reading and swap the around and check spark again. There may also be a problem with the power pack sending the initial voltge to the coil to allow it to fire.

 

[woodtick007]

Re: 1996 50hp Johnson No SPARK Top Cylinder

At the present time I have no spark from the top half of the coil. How can I test the coil? How can I test the power pack? I have a test meter if that will help.

 

[o/b tech]

Re: 1996 50hp Johnson No SPARK Top Cylinder

Unfortunately, you need a peak reading volt meter to accurately check the voltage coming out of the pack to the coil. It is more likely that the pack will actualy fail as opposed to the coil. The pack is the most common component to fail in the ignition system. Unless there is a physical problem with the spark plug wire going to the top cyl. it prob isn't the coil. Hope this helps.

 

[woodtick007]

Re: 1996 50hp Johnson No SPARK Top Cylinder

Unfortunately, you need a peak reading volt meter to accurately check the voltage coming out of the pack to the coil. It is more likely that the pack will actualy fail as opposed to the coil. The pack is the most common component to fail in the ignition system. Unless there is a physical problem with the spark plug wire going to the top cyl. it prob isn't the coil. Hope this helps.

I have a Blue-Point MT5868 Multimeter.... Can this be used to check the coil and or pack? Any suggestions?