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View Full Version : B&S reving?


jasonw
06-21-2010, 05:26 PM
What dose it indicate? I have a motor that will just rev up and down erratically no matter if its at idle or full throttle. I look at the carb and the throttle on the carb just bounces back and forth and back and forth. If I hold it opened it forces the lever to the stop position and kills the motor. Any ides?

Steve
06-22-2010, 12:17 PM
Off the top of my head I can think of two potential reasons. Either the governer or the carb float.

If the governer spring is weak it can cause this or if the float is bad it can cause the bowl to empty and then refill instead of being a steady amount of fuel.

Maybe another member has more thoughts on it though.

jasonw
06-22-2010, 01:57 PM
Off the top of my head I can think of two potential reasons. Either the governer or the carb float.

If the governer spring is weak it can cause this or if the float is bad it can cause the bowl to empty and then refill instead of being a steady amount of fuel.

Maybe another member has more thoughts on it though.

I checked and the governor was restricted but I didn't check the spring. Would a week spring cause this? I tore the carb apart and this far it looks fine. I gave it a good cleaning anyway but it didn't help the situation at all. Is there a process to tighten the governor spring?

swstout
06-22-2010, 09:28 PM
Here we have a lot of fine sand. My filter clogs rather quickly and I get the same effect you are experiencing. You might check it out.

Steve

jasonw
06-22-2010, 09:36 PM
Here we have a lot of fine sand. My filter clogs rather quickly and I get the same effect you are experiencing. You might check it out.

Steve

I have been working on it with the filter removed so I know that's not it. I am just about done producing a video for you tube of it. I will post a link when it is uploaded.

jasonw
06-22-2010, 10:31 PM
Ok here is the video. You can see no matter if its at idle or full throttle it still runs and revs the same.

http://www.youtube.com/watch?v=_wFDi5594tw
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Steve
06-23-2010, 01:31 PM
Do you have another similar sized engine that you could swap the governor spring with or even compare the tension of each?

Air Vane Governor
http://www.tpub.com/content/recoveryvehicles/TM-5-4240-501-14P/img/TM-5-4240-501-14P_142_1.jpg

Air Vane Governor
http://www.tpub.com/content/recoveryvehicles/TM-5-4240-501-14P/img/TM-5-4240-501-14P_142_2.jpg

Mechanical Governor
http://www.tpub.com/content/recoveryvehicles/TM-5-4240-501-14P/img/TM-5-4240-501-14P_142_3.jpg

jasonw
06-23-2010, 02:29 PM
Unfortunately no I dont. I think if I cant figure it out I will just disconnect it and run a solid rod from the throttle to the carb.

jasonw
06-25-2010, 01:00 PM
Common people. 111 views? Someone has to have an idea?

Steve
06-25-2010, 01:30 PM
I am thinking its gonna be the governor but another thing to consider is that the carb float can be gunk free and moving fine in the carb but if it is too old, it may not have the same float properties it originally had.

You can test a float by using a pair of needle nose plyers and submerging the float into a cup of hot water and look to see if any bubble are being released from the float that would signify a leak in the float.

jasonw
06-26-2010, 02:30 AM
I'm not sure exactly how the float would cause this. If it was filling with gas then it would overflow, if it were not moving down the bowl would not fill. You can see in the video where I manually hit the gas and it revs like its suppose to but the governor pushes back on it hard.