’89 Mercruiser 3.0L Ignition trouble

  • tdunahee
    Stevens Point, WI
    Posts: 11
    August 22, 2011 at 1:46 am #1238603

    A friend asked me to help him with a boat he just inherited. it is a ’98 Lund 1850 Tyvee with a 3.0L Mercruiser I/O. The engine is a breaker point ignition type. The boat has been in storage for several years and will not start. When I got to his house he had a battery charger hooked up and charging, but I noticed the ignition key was on. Once we removed the charger we attempted to start the motor. It cranked, but nothing else. I pulled a plug and found the plug dry. I checked for spark by grounding a plug against the block and having them turn the motor over. Nothing. We pulled the coil wire from the distributor and again, turning the motor over, I checked for spark here. Nothing.

    Any ideas?

    the_grump
    Le Center
    Posts: 612
    August 22, 2011 at 2:14 am #989911

    Pull the distributer cap and run some fine sand paper thru the points.

    tdunahee
    Stevens Point, WI
    Posts: 11
    August 23, 2011 at 12:33 am #990091

    I used a point file right away. No luck. The coil was tested today and is good. My friend then purchased new points and condenser and tried putting them in himself. Still no spark, but he doesn’t think the points are set right. I am going over tomorrow to take another look. Does anyone know the proper sequence for setting the point gap (The gap measurement is on the motor)? It has been too many years since I set one up. What position do you have the crank/distributor in when setting the gap?

    Another thing we noticed is there is only power to the “+” side of the coil while the engine is being cranked. Shouldn’t there be power here anytime the key is in the run position?

    tdunahee
    Stevens Point, WI
    Posts: 11
    August 23, 2011 at 12:35 am #990092

    OOPS! I just noticed I typed the boat/motor year wrong. It is an ’89 not a ’98.

    Tom P.
    Whitehall Wi.
    Posts: 3532
    August 23, 2011 at 3:59 am #990142

    Point gap at roughly 20 thousandths will get you in the ball park. Install the points turn the engine until the the points rubbing block are on one of the high spots on the distributor shaft set the gap. Once that is done I would run a jumper wire from the + battery to the ignition side of the coil and check for spark. If you then have spark it is either the ignition switch, the wires to and from the switch, or kill switch.

    tdunahee
    Stevens Point, WI
    Posts: 11
    August 24, 2011 at 12:39 am #990431

    Thanks! You’ve confirmed what I just relearned. It has been many years since I worked on an ignition system with points, so I’ve been doing some reading…

    Due to lousy weather here tonight we didn’t get a chance to try any of this, but I suspect the problem is in the wiring.

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