# David Brown throttle control



## ddflegal (May 13, 2012)

For years I had to use the choke to control the RPMs of my David Brown 3800 gas. I rebuilt the carb. I found a NOS carb in England. Then one day I ran my hand under the pre intake air heater section on the tractor. There is a tube that runs down into ta hole in the frame. I assumed this was a flooded carb drain. But, at the bottom of this tube is a ball valve that closes when the engine starts. I had removed it during the rebuild because it was blocked. Anyway, when my finger hit the threaded nipple, the RPMs immediately dropped from 1600 to 850. I tried the hand throttle and it was totally effective. The engine has run perfectly since. I mention this because I have other posts that have this problem. Hope this helps. Don


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## roreid (Jun 25, 2013)

I have a david brown 1200 and I have to hold the throttle control handle. it wont stay at the proper rpm it moves is there some way to stop this


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## Casemechanic (Jun 12, 2013)

Normally hand throttles on tractors have some form of a friction device to help set the throttle at a constant rpm. Look for a spring with a bolt through the centre of it somewhere in the throttle linkage. It may be hidden behind your dash. When you find the friction device, increase the pressure on the spring a quarter of a turn at a time until the throttle is able to be left at a constant rpm. Give that a try and see how you go. State of Origin tonight!, GO NEW SOUTH WALES!!!! Catch it on ESPN Sports


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