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Honda BF5A running rough

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  • Honda BF5A running rough

    I have a honda 5 hp 1997 that's running rough at idle and mid range.

    I changed the oil in the engine, lower unit, put in a new spark plug and fresh gas. I also checked the compression at wot (throttle rod disconnected and pulled) I raised quickly in a couple of pulls to 150 psi.

    After running it in the tank for 10 min at low speed the engine still ran rough missing at idle and mid range. I checked the spark plug and it was very dark so it seems to run too rich. I pulled the carb apart it looked clean but I noticed the idle screw was a 3 3/4 turn from bottom. What is the base setting for this screw? 1 1/2 turn?

    Is there risk of dommage to the plastic parts of the carb (choke mechanism) if I let it soak in solvent? which solvent do you recommend?

    Should I check the valve lash ? what is the spec and how I sould adjust it ?


  • #2
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    Re: Honda BF5A running rough

    for the general knowledge, I bought a shop manual on e-bay and it contained all the info I needed

    idle screw base adjustement 2 3/8 turn
    valve lash
    intake between .002 and .006
    exhaust between .004 and .007
    adjustement is made on a cold engine with piston at tdc on the compression stroke (aling the tdc mark on the flywheel with the mark printed on the ignition coil)

    I cleaned the carb and adjusted it near base adjustement and now it's running smooth, like it sould