5HP B&S tiller engine won't run

Discussion in 'Mechanic and Repair' started by Robert Doubrava, Oct 14, 2003.

  1. Robert Doubrava

    Robert Doubrava LawnSite Senior Member
    Posts: 342

    Got this engine from my Uncle recently. It's a 1973 model engine but it runs great, if it would stay running. :rolleyes: I just rebuilt the whole carb, replaced the tank gasket, diaphgram, etc. It will fire up, then run for a while then die out. Sometimes it will stay running on choke. Like I said, I cleaned out the whole carb. It has a new gas tank, and the fuel pick-up tubes are clean with no clogs.

    Help???
     
  2. ducky1

    ducky1 LawnSite Senior Member
    Posts: 252

    check the gas cap and make sure that it is vented. check the metering jet under the carb adjusting screw and make sure that it is clean and tight.
     
  3. Robert Doubrava

    Robert Doubrava LawnSite Senior Member
    Posts: 342

    Gas cap is venting, it's brand new. I cleaned out the metering jet when I rebuilt the carb. I cranked it up today and it ran pretty bad. It will not run unless it is on full choke, and when it is running, it pops and sputters really bad.

    Robert
     
  4. Grassmechanic

    Grassmechanic LawnSite Silver Member
    Posts: 2,697

    I'd revisit the diaphragm and check it very closely. Sometimes it will have a slight pinhole that cannot be seen. I've rebuilt those carbs before, and have had a brand new diaphragm turn out to be the culprit. Also, check the mating surfaces of the gas tank and the carb. They must be perfectly straight.
     
  5. If you ruled out the carb--
    Dying after it warms up - could be the armature coil, usually doesn't show up until warm.
    Also 1973 engine would have points & condenser, I seem to remember a bad condenser could cause this problem, fortunately I haven't seen any engines with points for some time.
     
  6. Robert Doubrava

    Robert Doubrava LawnSite Senior Member
    Posts: 342

    That's one thing I didn't check. The ignition system. When I had the blower housing off, I tried to remove the recoil starter ratchet, but I couldn't so I just left it alone. Looks like I'll have a hard time removing the flywheel, too as it's pretty rusted up. Will try working on it tomorrow and see what's up with the ignition system.

    Robert
     
  7. barnard

    barnard LawnSite Senior Member
    Posts: 618

    It's fuel system. you are missing something. If it was ignition it would not be affected by the choke position. Is your tank one with a small reservoirin it just under the carb. Similar to a float bowl. Does it have a hole in it.
     
  8. NCSERVICE

    NCSERVICE LawnSite Member
    Posts: 206

    It sounds like you have some water in your fuel tank. however if you think its spark, spend $7 on a napa inline spark tester so you can watch it as it runs.
     
  9. Robert Doubrava

    Robert Doubrava LawnSite Senior Member
    Posts: 342

    I got the ratchet and flywheel off yesterday. The contacts on the condenser and the points were pretty corroded. I got a file and cleaned them up. There isn't any water in the tank, I'm sure of that. The gas tank has some sort of thing right below the carb, I think it's called a baffle??? Also, I found out that this engine has an electronic ignition installed. The wires coming from the points and stuff have been cut and it has the Magnetron thing under the coil. I'm not sure if this will help, but this engine has a Pulsa-Jet carb.

    Robert
     
  10. Grassmechanic

    Grassmechanic LawnSite Silver Member
    Posts: 2,697

    Also, if I'm not mistaken, you need to "pre-load" the diaphragm to set the choke plate.
     

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