Johnson 6hp…won’t start

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  • hirschlt37

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 31
    Topics: 27
    #2685

    I’m sure you guys have seen this before…but I need to get some good advice: The little Johnson has great spark, looks like it’s getting plenty of fuel to the carb(rebuilt fuel pump),new plugs, starts with a shot of ether(not too much) and runs with a little choking til she warms up….then runs great. If you stop it, you can restart while she’s warm. Then nothing…I haven’t rebuilt the carb.—I will check compression….but don’t think this is the issue…I had champion 6 heat range plugs and went to 8’s…..it idles a little better…looking for a few suggestions…it’s a sweet motor when it runs!


    fleetwin

    US Member - 2 Years
    Replies: 4744
    Topics: 46
    #25013

    Well, kinda hard to say. You have to spray ether in the carb to get it started cold, but will start ok once warmed up. The engine runs ok once warmed up and will continue to run OK at high and low speeds, no stalling/surging problems, correct?
    Once the engine is allowed to cool down, it will NOT restart without the ether, correct?
    Based on my assumptions noted above, I would have to say there is something wrong with the choke/linkage. The only real issue you seem to be having is getting it started cold, once started it seems to run fine, and starts up OK while still warm.


    Doug Wilson

    US Member - 2 Years
    Replies: 239
    Topics: 29
    #25018

    might not hurt to go through the carb if it has not been done, but agree with fleetwin check that the choke is working right

    Doug

    how is it motors multiply when the garage lights get
    turned off?


    sedover


    Replies: 18
    Topics: 6
    #25101

    Back to basics; compression check, spark check (1/4" gap), then the carb. Don’t need J8’s stay with 6’s. If engine runs cold check thermostat.

    Remember the crankcase has to suck the fuel air mix in, so, poor compression will make it a hard starter because it is suction on the backside. A worn engine will often need to be wetted down to seal.

    Start with the basics first and then proceed. Other little things come into play now that these engines are 40-50 yrs old.

    Steve


    billw

    US Member - 2 Years
    Replies: 2071
    Topics: 66
    #25102

    I agree with the basics check, first. You should know these things about your motor, whether it starts well or not. Then the choke check. After that, I would take the plugs out and spin the engine over with my hand. You should hear two squeaking noises per revolution, indicating the the reed valves are sealing tight. If you don’t hear these two squeaks, maybe you have a problem there…

    All that being said, if you are trying to start a 6 with the tiller handle indicator on "start," when cold, well, that just ain’t gonna happen. I find they need nearly full throttle when doing a cold start, like the 4 hp models. Of course, drop the throttle as soon as the engine starts to come alive, to prevent any over-revving.

    Long live American manufacturing!


    fleetwin

    US Member - 2 Years
    Replies: 4744
    Topics: 46
    #25105

    Bill makes an excellent point about that throttle position indicator, advance it past start for cold starts!


    collectorinspector


    Replies: 145
    Topics: 21
    #25220

    Yes

    If it is a new motor to you disregard what it says on the twist grip indicator.

    Full choke twist past that indicator and if all is well it WILL start……..they always do. It will start somewhere. The choke will open the butterfly just slightly all by its own linkage on the side of the carb. That is not adjustable.

    However

    I would suggest looking at the nice little cam under the ignition plate that opens the carb up via a follower

    The "sinc between them " should be set……..maybe someone could post how and what marks etc. We do not know what your 6 is yet?

    Different model years have differing mark to throttle linkage settings.

    If everything else works well……….a good place to look at……….easy.

    Just need to know exactly what year model for that setting is all. Marks are obvious.

    Then maybe the Start position on the twist grip will line up………..kindof…….

    B

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