A friend of mine, recently came to me about a problem with his gas golf cart. He had replaced several parts, including the carburetor, and everything seemed to be working pretty well with one exception. If he were to run along at a fairly high speed and then let off of the accelerator for a few seconds and then step down on the accelerator again, the cart would “backfire”. Not just a little “backfire”, but a formidable explosion.
When I wrote the book about gas cart repair (click here for more information), I included chapter 11, called “Performance Problems”, in which I go into some of the more common problems that people have with gas carts, and this symptom is covered at length in that chapter. For this post, however I’ve included the following, as a shorter version:
Earlier in the book (chapter 10) refers to one of the parts of the carburetor as a screw that sets the minimum position that the throttle plate can rest in (with the accelerator back in the home position). There is no “idle” on a golf cart. The screw (not an idle screw, as some people mistake it for) is really a low speed adjustment. It should be adjusted so that when the accelerator is let up on, the throttle plate comes back to being almost closed. To adjust the screw, you should back it off (with the accelerator in the rested position) until the throttle plate is totally closed and then only advance it (clockwise) until the screw touches the “flap” on the throttle plate and then screw it in about another one quarter to three eights of a turn. What happens If the throttle plate doesn’t return to a “closed” enough position, (when you let off of the throttle), the engine continues to draw carbureted fuel into the combustion chamber. While you have let off of the accelerator, the engine doesn’t fire, because letting off of the accelerator also shuts down the ignition (the accelerator microswitch). But, once you step on the accelerator, the accumulated mixture that is in the chamber, the exhaust, etc., goes BOOM. Another problem can be that even when the carburetor is adjusted properly, if the linkage is “gummed” up (or a cable is bad) and doesn’t let the throttle plate return to “home” then the adjustment is meaningless. The linkage needs to be looked at closely, to be sure that nothing is holding up the closing of the throttle plate. Just let the accelerator return to the rested position, and check to make sure that the “flap” is touching the screw that has been adjusted.
Ron Staley has published the following books, and you can get more information about them by just clicking on each title below:
Electric Golf Cart Repair 101 (and a half)
Techniques, Tips, Tools and Tales
Gas Golf Cart Repair 101 (and a half)
Techniques, Tips, Tools and Tales
4-Stroke Golf Cart Engines Explored
What Makes Them Tick
By an old Slot Machine Mechanic