Mcculloch 4hp no start

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This topic contains 132 replies, has 16 voices, and was last updated by  joesnuffy 8 months ago.

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  • billw
    US Member - 1 Year
    Replies: 969
    Topics: 33
    #75192

    Okay, well, you’re testing the spark with a spark plug, in both cases. A regular spark plug gap of more or less .030" is not enough to really test the system. It is easier for spark to jump that gap under regular, atmospheric pressure than it is under 90 psi. When you put the plug in the engine, and put fuel and compression to it, it may NOT fire. This is why the spark has got to jump at LEAST….at the very, very LEAST…..3/16" in the open air. A quarter inch is better, and very commonly obtainable.

    If you don’t want to make it jump the 3/16", then at least try closing the actual plug gap down, WAY down, to .010" and see if the engine will fart on that.

    Also, if you’re trying to start it with the mag lever position in that video, that’s still not far enough over to port. Should be 3/4 of the way over to port. And, when in that position, the actual throttle plate inside the carb should also be opening about 3/4 of its travel.


    john8504
    US Member - 1 Year
    Replies: 117
    Topics: 18
    #75202

    I ordered a spark tester and it should be in Friday. Waiting for it to arrive.


    joesnuffy

    Replies: 285
    Topics: 20
    #75224

    Since your waiting on a spark checker. You could be doing these while waiting their just suggestions to see if you can improve your spark.

    I’m going to post a few tools and tricks I use to get a hot blue spark every time I have been taught many of these but they pretty good ones.

    I am posting a pic of a new old stock techumseh coil here which is most likely like yours notice notice their is no plug wire in it like the new Chineese jobs these days. Their is a metal spike in the center of where the plug wire goes and their normally shaped like a wood screw so you can turn your plug wire into it while pushing it in and it bites in and won’t just pull out. That is normally a place where the wire inside the plug wire copper strand rusts, burns off etc.

    https://www.ebay.com/itm/NOS-tecumseh-2 … XQySpROMFx

    If you try and unscrew your wire from your coil while gently pulling it out then once its out take a look to see if the metal inside the spark plug wire is burn or rusted. Napa might sell you a piece of spark plug wire 7mm with a copper core like 1 footlong if not I normally shorten the wire on the coil end like 1/4-1/2 of an inch depending on how long it is and how much I can cut off without making it to short then I screw it back into the coil.

    Now on the other end where the spark plug boot goes I normally spray it with wd-40 or some type of oil to help the plug wire to pull out of boot. I also use a small screwdriver and pushing the metal spring clamp outward while pulling on the spark plug wire. Sometimes the plug wire just rips off but I then work the metal spark plug clamp out of the spark plug boot with a screwdriver and some needle nose pliers. I shorten it on that end like 1/4 inch and leave a little of the copper wire hanging out so when I re-assemble it in the actual wire is touching the spark plug clamp see pics. This helps a bunch with energy delivery to the plug The pics will help you see it. If you can’t get a new piece of spark plug wire at least use electrical tape and tape up what you have after you make repairs on both ends of the plug wire.

    I am also showing you a cheap spark plug gap checker their available at places like harbor freight I have the one in picture adjusted to like 1/4 inch of fire jump the alligator clip goes to ground.

    Clean all the magnets on flywheel, clean the ends of the laminate shoes that’s the part that almost touches flywheel while it spins should be 3 spots, clean your ground wire terminal and the screw where it goes thru the condenser make sure condenser is grounded well also you can see those wires in the picture of the coil. Clean the terminal from the coil where it connects to your points.

    Hope that helps,
    Joe


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    jeff-register
    US Member - 1 Year
    Replies: 999
    Topics: 40
    #75232

    Please look inside the coil for a point of termination, should have PIN IN THE CENTER, no connection causes an ark & the pin goes away. H.V. is weird to work with & odd glitches. It’s been said, Get a meter on electrical parts. Check 4 crank side slop too. It would at least sputter with starting fluid
    (& timed correctly) Any crankcase leakage is not good,
    Edit: Hold your reed plate to light to check reed seating after cleaning


    john8504
    US Member - 1 Year
    Replies: 117
    Topics: 18
    #75469

    @joesnuffy. So if I understand you correctly, turn and pull the wire from the coil and it will come out? Then look to see if it is burned or whatnot? Do I just reverse steps to reinstall said wire into coil? Also what do i secure wire with?

    Also I am not quite sure why my name hasn’t shown up red yet? Hmmmm.


    billw
    US Member - 1 Year
    Replies: 969
    Topics: 33
    #75471

    @joesnuffy. So if I understand you correctly, turn and pull the wire from the coil and it will come out? Then look to see if it is burned or whatnot? Do I just reverse steps to reinstall said wire into coil? Also what do i secure wire with?

    Also I am not quite sure why my name hasn’t shown up red yet? Hmmmm.

    I was a member since 1983 and I had to ask the website administrator to make it red. Once I did that, it was no problem. Done very quickly, once I asked.


    john8504
    US Member - 1 Year
    Replies: 117
    Topics: 18
    #75472

    Thanks Bill!

    Going to get a new spark plug wire and try that route to see if I can get my spark to jump the 3/16 "


    Attachments:


    joesnuffy

    Replies: 285
    Topics: 20
    #75493

    John,
    Most actual vintage techumseh coils the ignition wire is removable and replaceable. You know what a wood screw looks like their is a spike where the ignition wire goes into the coil right in the center that is what holds the wire inside the coil. Here is a video of how to replace ignition wires and what the spike looks like. I have replaced a lot of ignition wires on older outboard motors it almost always makes them run better if not it at least gives me piece of mind that the ignition wires are good and I’m not loosing spark through cracked wires. This is true especially when trying to figure out whats wrong. I normally buy a entire roll of the 7mm copper strand inside wire which lasts me a while but in your case you may just need a foot or 2 napa most likely sells copper strand ignition wire by the foot. Marine engine does sell it by the foot.

    hope that helps,
    Joe
    Replace ignition wires outboard

    Ignition wire by the foot
    http://www.marineengine.com/newparts/pa … OMC0772584


    john8504
    US Member - 1 Year
    Replies: 117
    Topics: 18
    #75510

    Yeah I ended up finding some at a local auto shop. Napa, advance auto and Autozone didn’t carry it. I was surprised.


    john8504
    US Member - 1 Year
    Replies: 117
    Topics: 18
    #75530

    Eureka!!!!!!

    I want to that everyone for their help! She runs!!! Nick Kramp emailed me and gave me a few more points. Turns out the lasts few problems were a spark plug wire, wire clip, and a weak magnet on the flywheel. The donor motor was worth its weight in gold!!!

    Much thanks

    bobw
    bobw
    US Member - 1 Year
    Replies: 320
    Topics: 14
    #75531

    OUTSTANDING!! I’ve followed this thread since your original posting and know it’s been a frustrating process. That’s the great part about this forum – lots of folks who are willing to share their experiences and help solve a problem. I’m sure it was exciting when it finally fired off! How about posting a video of it running?

    Bob

    1954 Johnson CD-11
    1958 Johnson QD-19
    1972 Evinrude 25202


    john8504
    US Member - 1 Year
    Replies: 117
    Topics: 18
    #75532

    Sure will. I have to put the lower unit back on and get a tub of water for it


    john8504
    US Member - 1 Year
    Replies: 117
    Topics: 18
    #75534

    Now that it runs, anyone know how to get a big dent out of a gas tank?

    bobw
    bobw
    US Member - 1 Year
    Replies: 320
    Topics: 14
    #75539

    Never done it myself but here’s an article I saw some time ago about removing dents by pressurizing the tank and applying heat around the dent to make it pop out. Obviously want to be sure the tank is totally clean of any fuel or fuel vapors.

    https://conductorjonz.wordpress.com/201 … sea-horse/

    Bob

    1954 Johnson CD-11
    1958 Johnson QD-19
    1972 Evinrude 25202


    joesnuffy

    Replies: 285
    Topics: 20
    #75545

    Congrats, That to me is the best feeling when you work on a motor that challenges you and when you finally get it right wow its terrific.

    Joe 😀

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