zenith carb running rich
- Thread starter richbatch
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ronsealdeath
Sagging Member
- Posts
- 1,851
- Location
- Swansea, Wales
ronsealdeath
Sagging Member
- Posts
- 1,851
- Location
- Swansea, Wales
Bugger its to big to attach. Ive done a post on this before ifyou can search for it.
Was iton a gas analyser you found out it was rich? if so dont worry these 2.25s on 36iv like to run rich. If its not causing an issue id leave it.
It does day how in haynes manual but its a bit simplistic!
Ok at a keyboard today not a stupid phone. If you must re-set the idle Its advisable to record the number of turns out the needle is before you do anything. Wind it all the way in gently, note the number of turns and stop when it seats, don't tighten it up or you'll bend the needle. Then unscrew it 2 full turns (720 degrees). Start the engine and warm it up fully so its idling with no choke at about 5 to 600 RPM ideally. Slowly turn the needle a quarter turn out to richen (let more fuel past the needle) and listen to the engine speed, it should increase. Give the engine time to respond to the quarter turns. Keep doing this until the engine speed starts to drop. Stop here and lean it out until you get to the peak RPM as it were (think of the it as the peak of a parabolic curve if plotted on a graph). Now you'll be about there but your idle speed will be too high. Drop the idle speed to 5/600 RPM again using the throttle stop screw and repeat the process. Usually needs 3 goes. This should be about right but its not an exact science and you'll probably want to fiddle with it. Adjust it again after 50 miles to make sure its right. Check your plugs at this point and see if its looking rich or lean etc...
Was iton a gas analyser you found out it was rich? if so dont worry these 2.25s on 36iv like to run rich. If its not causing an issue id leave it.
It does day how in haynes manual but its a bit simplistic!
Ok at a keyboard today not a stupid phone. If you must re-set the idle Its advisable to record the number of turns out the needle is before you do anything. Wind it all the way in gently, note the number of turns and stop when it seats, don't tighten it up or you'll bend the needle. Then unscrew it 2 full turns (720 degrees). Start the engine and warm it up fully so its idling with no choke at about 5 to 600 RPM ideally. Slowly turn the needle a quarter turn out to richen (let more fuel past the needle) and listen to the engine speed, it should increase. Give the engine time to respond to the quarter turns. Keep doing this until the engine speed starts to drop. Stop here and lean it out until you get to the peak RPM as it were (think of the it as the peak of a parabolic curve if plotted on a graph). Now you'll be about there but your idle speed will be too high. Drop the idle speed to 5/600 RPM again using the throttle stop screw and repeat the process. Usually needs 3 goes. This should be about right but its not an exact science and you'll probably want to fiddle with it. Adjust it again after 50 miles to make sure its right. Check your plugs at this point and see if its looking rich or lean etc...
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