OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines B&S 98902 Idle Speed

Hi,

I have a Briggs 98902 0385 that refuses to idle sensibly. It always seems be revving quite fast, even at the lowest throttle setting. I have run it without the air filter to observe the governor mechanism and at the lowest throttle setting the lever on the carby is fully 'backed off' ie if I move it off the stops it revs even higher. The govenor seems to be working, from cold I can see it preventing the motor from stalling. Everything else is fine, starts easily and runs great when cutting. I'm sure I had a B$S a few years ago that idled sooo slowly and was sweet as a nut... Or am I dreaming?

Thanks Guys

Mark_WA,

Click HERE for the owners manual and it will have information on the engine. For the parts list for your engine click HERE and have a look at page 5 for what I am talking about.

As to your high reeving of the motor you have a spring which goes to a metal section at the front of the motor (on the carby). This is where you can adjust the RPM by bending the metal section that the spring is connected to.

Try this and see how you go.

Hi Bruce,
thanks for the reply...Perhaps I wasn't explicit enough in my previous post... The steel swing plate that the throttle cable is attached to is back so far as just not actuate the kill switch. The arm on the carby intake connected to the govenor is totally back one way, against the stops, moving it away from the stops increases the revs further. There doesn't appear to be any adjustment screws on the carby........

Mark,

1. Did you have a look at the drawings?

2. Have you had the carby off?

If so did you put the gov wire in correctly as some times don't put it in correctly and the machine rev's high.

Can you post a picture of the carby on the mower. It will help a lot.

Hey Bruce,
yes, I've had the carby off. I found the inlet sealing ring and retaining ring detached from the carby, so a serious air leak! This improved things but still revving pretty high.
The gasket/diaphragm is a bit ragged, I'll try and get one today. The closed chamber on the fuel tank was very dirty. I've added a pic of the carby. When supposedly idling the venturi control arm is in the fully closed position. When run without an air filter I can slow the idle down by resstricting the air intake with my hand. The long pickup tube with the filter on the end is very hard to blow through, is this normal?

Hope this will help you to help me!! - Mark

Bruce,
I have been scouring the net for linkage images.. I could be wrong but it looks as if the the throttle valve linkage has been assembled 90 degrees out of whack. Ie. the actuator arm should be central to the carby body, each end of the actuator being limited in movement by the centre stop on the carby.
I also notice that I have another spring missing 691859 governed idle spring..... What a saga!

Mark_WA,

You have the link wire in the wrong hole and that is your problem with high RPM.

Problem solved! The throttle valve actuator had been assembled incorrectly and never closed fully in that position because of the centre stop. Interestingly everything else seemed to work smoothly even though it was 90 degrees or so out of position!
Thanks to all who replied... Yes I don't need the extra spring, there is nowhere to anchor it to!
Attached is a pic of the correct assembly position.

Mark in WA