Buy Evinrude Outboard Parts

Announcement

Collapse
No announcement yet.

1996 3 cyl 50 weak spark

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • 1996 3 cyl 50 weak spark

    I don't know if i am in the right forum here as i am new to this board but I recently bought a pontoon boat with a 3 cylinder 50 Evinrude. The problem i am having is that at low speed the top cylinder stops firing. If i rev the engine up to about 3000 in neutral the engine will eventually run on all three but will return to running on two cylinders at an idle. I have tried interchanging ignition coils with no help and the previous owner has replaced the switch box and voltage regulator. As i am new to these engines any guidance as where to look next would be much appreciated.

  • #2
    Yes you're in the proper forum, but unfortunately, it appears that I am the only one hanging out here... and I retired in 1991, hence the design and circuity of your engine may be foreign to me. However, there are some problems that are common to all engines of this type that I will dwell upon.

    However.... DO NOT ever exceed a rpm of 1800 while the engine is in neutral as you are inviting a runaway engine scenario which is indeed frightening. The rpms will continue to on to exceed factory recommendations, the throttle butterflies will have no effect, the engine will be dieseling and turning the key off or pulling spark plug leads off will have no effect... it's not a pleasant happening!

    ************
    Questions.... When this present problem is taking place, with insulated pliers pull the boot off of that #1 spark plug. Can you hear the spark jumping between the boot and the plug? If you insert a #2 philips screwdriver tip into the boot, will spark jump from the screwdriver shank to the powerhead? (Wondering... is it fuel or ignition?)

    With all spark plugs removed, at cranking speed, the spark should jump a 7/16" air gap with a strong blue lightning like flame... a real SNAP! Does it? Note that the gap is important!

    All plugs still removed: Compression... what are the psi readings of all cylinders?
    **********

    Your problem..... Check the stator under the flywheel to see if they're are any cracks and/or a sticky looking substance dripping down on the powerhead area. if this dripping exists, that would result in a AC voltage drop to the powerpack's capacitor which in turn would result in weak, erratic, and eventually no ignition/spark.

    Various connectors are prone to problems as follows:

    (Electrical Pins/Sockets - Poor Connection)
    (J. Reeves)

    The electrical rubber connectors that house a series of Pins and Sockets within them have a flaw which can easily be overlooked. The the pin or socket (or both) has been known to be pushed back slightly when pulling them apart and pushing them back together when replacing a component or doing test work.

    Also, the wire that is attached to these pins and sockets has been known to break away from the pins/sockets which results in either a very poor or no connection at all. I've found many instances where the wire is held tight in the rubber connector by pure friction but in reality is not making any connection.

    Be sure to check all of those rubber plugs for the proper pin/socket position and wiring attachments.
    ******************
    NOTE: Spark testers can usually be found at any automotive parts store, OR the following can be built.

    (Spark Tester - Home Made)
    (J. Reeves)

    You can use a medium size philips screwdriver (#2 I believe) inserted into the spark plug boot spring connector, then hold the screwdriver shank approximately 7/16" away from the block to check the spark or build the following:

    A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

    Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:

    ..........X1..........X2

    .................X..(grd)

    ..........X3..........X4
    Last edited by Joe Reeves; 07-17-2017, 07:18 AM.

    Comment

    Working...
    X