Racing Idle

[dlcentral]

Sounds like possibly the gov needs adj.Loosen up cinch bolt that holds gov. shaft that comes out of eng.open throttle wide open,with a small screwdriver turn inner shaft rod IN THE SAME direction as the shaft moved when throttle was opened.tighten up cinch bolt.That's it. good luck with it.

[JeffN]

Still having problems with that 10HP Briggs. Model #220707 Type: 0149-01. It seems as if though the engine wants to race or idle really high. I have started with an initial adjusment of turning both the top and bottom adj screws on the carb out 1-1/2 turns and I have backed off the idle speed screw practically out all the way. By doing this I can get it to start and run somewhat normally but not terribly smooth with the throttle on slow. As soon as you move the throttle up a bit towards fast it it idles so fast you'd think it was going to take off. Is this typical of this particular engine? At this time I don't have the pulleys or belts installed but when I initially fired it up I did and it still idled fast. I am new to this and I don't want to wreck the motor. If anyone has any ideas I would greatly appreciate it. Thanks Jeff N.

[JeffN]

Here is what I did: Took off all linkages to the carb, started engine, rotated throttle clockwise to increase speed and still seemed to idle faster than normal. At this point I am at a loss since none of the linkages were connected to the governor. Could a faulty carb cause this condition? I do have another carb off of another motor I know runs correctly if this could be a probable cause. Does not having any of the pulleys or belts connected contribute to increased RPM's? Could incorrect wiring from the solenoid/battery to the engine cause the engine to run in such a way? Thanks again.

[JeffNemes]

Now I'm confused. If you OPENED the throttle to INCREASE speed how is that suppose to effect the idle speed? Start the engine and CLOSE the throttle (butterfly, plate, flapper) to SLOW the engine speed. If the engine stalls adjust the idle speed screw so the throttle plate is just cracked open. Then do your idle mixture needle adjustment. If the engine stills races when you do the above, check the throttle shaft for excessive wear, or the carb to manifold gasket. Remember, if you have all the springs and linkage disconnected you have to control the throttle and choke plates right at the carburetor with your fingers.

[dymondclay]

The condition you describe is NOT normal. I suspect you have linkage, governor, or mechanical problems. 1) Disconnect all cables, linkage, and springs going to the carb. 2) Check the throttle shaft for looseness (an extremely worn shaft can cause the engine to race and prevent proper adjustment). 3) Check your choke and throttle cables/rods for binding. 4) With all linkage still disconnected, start the engine. Let the engine warm up. Open the choke. Adjust your idle stop, low speed and high speed mixture screws. 5) At this point the engine should idle smoothly, and should speed up smoothly as you open the throttle by hand. 6) Reconnect the thottle & choke cables/rods. 7) Refer to your engine manual for correct connection and adjustment of governor springs and linkage.

[Hogg]

Note that on some B&S 10HP (all?) the governor pulls the throttle back to the set engine speed. In other words, they are started in a wide-open throttle plate position and the governor pulls the throttle closed. Without the governor the engine will certainly race. It's possible that there is a problem with the governor, if all linkage connections are correct. If the throttle plate has been serviced, it is also possible that the arm which is attached to the end of the throttle shaft has been replaced 180 degrees off. This allows the connection of the linkage to be made and appear correct but actuates the throttle opposite of what it should. So as the engine is started and runs up in speed, the governor does not throttle back, but instead allows wide open throttle position. If the motor is run in this position for any length of time, it is possible to do some real damage. There's nothing like the sound of a 10HP B&S turning 6,000RPM. It'll make dogs howl all over the neighborhood. Tim

[JeffN]

Thanks for the suggestions. I will give these a try tonight and let you know how I make out. I just picked this motor up and bolted it on and these are the problems I encountered.

[JeffN]

What I meant to say is that with all of the linkage off I can close the throttle and get it to idle pretty well but if I open the throttle to increase speed it still seems to turn higher rpms than I am use to and vibrates a bit. I don't think the crankshaft is bent to cause the vibration. Could a faulty carb cause this to happen? Should my next step be to try a different carb on this engine? Sorry to be so much of a pest. Thanks again.

[JeffN]

You're not being a pest. I just wanted to make sure we were using the same terminology. If the engine idles smoothly with the throttle closed, that’s a good sign. Now the governor linkage and springs must be reconnected correctly and calibrated properly. To do that you will need to refer to your engine manual. If the governor isn’t operating as it should the engine can over-rev and cause serious damage.

[SmilinSam]

Another problem with a racing carb I have found on occasionis that sometimes when putting the brass tube ( ahead of the main jet) back in it runs up the side of the carb body rather than going into the hole it is supposed to. When this happens it props the butterfly open at full throttle plus. Just something else you can check on. Keep Smiling, Sam