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bobspets

Honda SP overhead cam mower starting problem

bobspets
9 years ago

Honda overhead cam SP mower starts runs 3-5 seconds quits does not restart Sparkplug replaced aircleaner removed. Next?

Comments (7)

  • bill_kapaun
    9 years ago

    Fuel shut off valve turned ON?

  • tomplum
    9 years ago

    Sounds like it could use some carb service. When was the last time it ran?

  • bobspets
    Original Author
    9 years ago

    I appreciate the replies.

    I believe the fuel shutoff valve is in the correct position, but it is worth a second look. As to last time it ran not certain, as it came from a friend who was not using it about a year ago when he gave it to me. I should also mention that I cleaned the carburetor with spray cleaner it still would not run and would only start with a shot of starting fluid. In the past when I had engines that wouldn't start I could get them running by spray cleaning the carburetor then when they started just continuing to spray the carb cleaner would keep them running for a few minutes then they would eventually blow some thick contaminants out the exhaust till it was clear and then run on their own.

  • tomplum
    9 years ago

    The part that plugs on these carbs is the small tube and jet that are in the center of the carburetor stem. If you decide to remove the carb, watch over the position of the spacers and gaskets. You can many times remove the bowl and blow up through that assy with spray carb cleaner and forced air w/o removing the carb from the engine if you are creative. You could also have an instance where the valves are sticky from varnish deposits. Usually you detect a popping along with the struggle to run. From your description- seems more carb related to start with anyways.

  • 1saxman
    9 years ago

    Fuel not getting to combustion chamber. Since you don't know what may have happened to it in the past, you have to start from scratch. With fuel in tank and gas valve 'ON', loosen the lower side fuel bowl gas drain - have a catch pan under it. You'll probably get some crud out and gas should freely flow from the tank out of the bowl drain. If anything comes out, let it drain for a minute to flush out dirt.
    If fuel does not flow out, remove the gas tank cap. If fuel now flows, cap vent may be plugged (bug nests, dirt, grass chaff, etc.). If still no gas flow, switch the gas valve back and forth. It should be 'ON' with the handle turned in line with the fuel hose but check both ways. If still no flow, take fuel line off the carb. With gas valve in what you believe to be the 'ON' position, take a large rubber syringe with a tapered snout, stick it in the fuel line and work the line as you would a toilet plunger, trying to blow back into the tank with it. The screen over the fuel outlet in the tank might be covered in debris. If this works, clean out the tank, put everything back together and try to flush the fuel bowl again with the gas drain bolt. Once you get fuel to the bowl, it should run.
    If gas does drain when you loosen the drain bolt the first time, and the fuel looks clean, then you have a pretty good idea that the restriction may be in the carb as outlined in the preceding post.
    Have you checked the carburetor screws for tightness? Be very careful - these long screws tend to strip the aluminum threads in the engine. Either you can turn them with light torque or you can't, in which case they are probably okay.
    Let us know how all this turns out and I or somebody else can probably take you into the next phase which would most likely be internal carb or leaking carb gaskets.

  • bobspets
    Original Author
    9 years ago

    Thanks for the followups. When it stops raining here I'll give it a go and report back.

  • 1saxman
    9 years ago

    I left something out - old fuel or water-contaminated fuel. If you're trying to start it on old gas that was in the tank when you got it, that should be the first to go. Drain the tank through the fuel bowl as above and replace with fresh fuel.