Sudden Loose of power at low RPM
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joeweber
- Posts: 58
- Joined: Tue Jun 26, 2007 4:39 pm
Sudden Loose of power at low RPM
I spent years chasing the elusive proper adjustments for my Dual 40 ID carburetors that I have mounted on my 1700 cc bus motor that is in my sand rail. Well over a year ago I got it running great, the Idle was a littler high but it runs great. I was out running around following a buddy down the trails and it started loosing power like it was missing. As I continued over the weekend it got worse. So I replaced the spark plug, wires and cap. No change. To keep it running at the lights I have to turn up the idle screw. I pulled out the jets and cleaned them and no change. I did find that if I floor it, it runs great but at low RPM it runs like its missing. I assume that the idle circuit must be plugged and if so, do I need to rebuild the carburetor or is there a easy fix. I have never taken a carb apart but I can learn. While it was at Idle I disconnected up to two plugs 1 & 4 with no change in the running. There is spark so it must not be getting fuel?
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wildthings
- Posts: 1171
- Joined: Thu Jun 03, 2004 12:42 am
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joeweber
- Posts: 58
- Joined: Tue Jun 26, 2007 4:39 pm
Carb cleaner
I new about spray carb cleaner but did not know they had it for the gas tank. I will try that.
I do believe I solved the problem though, and this may help others. The diagram for the carburetor did not show clear the idle jet location and I was cleaning the wrong part, after I cleaned the idle jets it ran a whole lot better. As I was tuning it I found that if the idle is set too low on a duel carb the one half of it does not get enough fuel to make a noticeable adjustment. I kept trying to change it but their was no difference in the sound of the motor. I turned up the idle and then adjusted it, suddenly I could hear the difference as I tuned for best lean. I then did the same to the other side. It now is running better than ever.
I do believe I solved the problem though, and this may help others. The diagram for the carburetor did not show clear the idle jet location and I was cleaning the wrong part, after I cleaned the idle jets it ran a whole lot better. As I was tuning it I found that if the idle is set too low on a duel carb the one half of it does not get enough fuel to make a noticeable adjustment. I kept trying to change it but their was no difference in the sound of the motor. I turned up the idle and then adjusted it, suddenly I could hear the difference as I tuned for best lean. I then did the same to the other side. It now is running better than ever.