OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Four Stroke Lawn Mower Frames 500 series B&S not reving

Hi Bruce & Co
I've got a New 500 series B&S motor(the one with the crappy plastic carby), when it's running the revs won't go much higher than base idle. Motor starts first go, idles fine, just no revs. I've check all the links and springs on the carby and governor, they seem ok.
Need a little bit of direction on what to look for now?

Ta
Steve

Have you pushed on the throttle butterfly's lever directly, to open the throttle? If the engine responds to the throttle properly, but not to the governor setting, you have a simple external mechanical problem in the control, the cable or the governor. Sounds as if that will be the case, but it needs to be verified.

I've tried the cable and everything works. You can rev the motor by moving the governor arm. To me it seems like the springs from the governor aren't strong enough to pull the throttle butterfly open when the cable control is used?

I'm not familiar with the governor on that model B&S. Bruce is the man.

hi stevea, i had similar problem lately with similar mower. the problem with this unit , was as you suspected not enough gov. spring tension.but dont mess with the springs just yet . i think it may be a chinese b&s that bruce refers to . i found that the whole throttle/gov. bracket is as soft as butter & also is the leading edge of the mower, so a little bending in this area ,can be done by hand, should restore spring tension, cheers johnno

Steve can you post a picture of the carby area showing the gov spring as ozziejohn said that the engine is more than likely one of the China made ones. This is easy to tell as the casing has ripples in it.

I have been noticing very poor quality steel and as they used to say plastic is as strong as steel years ago and nobody would believe that but guess what, plastic is now stronger than the steel that is being produced.

Thanks for the replies.
I'll try to get some photos uploaded tomorrow after work.

Steve

Hi Johnno, and a big warm to the forum!
You will find us a friendly bunch here as we all love to learn new things and tinker here
We also love to see photos of your projects.
We ars often online in the "Chatroom" lounge between 8 and 9pm (AEST) please drop in and say hi!!
Hope that you're enjoying your retirement mate,

Finally got some pics.See what you can make out of it.

stevea,

In order to adjust the speed you will need to twist the bracket (end of the longer spring) slightly towards the front of the mower and this will increase the spring pressure causing the mower rev higher.

Ta
I'll give it a try.