Recently finished my SN build. Having a few issues but confused on whether it is in need of a carb adjustment or a new waterbox.
The engine is as follows:
705 bore on a 61x cylinder block
ADA 35 cc head (~180 PSI)
Factory Mod B-pipe
Stock 38 62t carbs
- Needle/seat 1.5
- Hi 135
- Lo 75
Unfortunately I don't have anything to test pop off pressure of the carbs so tuning is a real pain. Recently when I took the ski out it seemed to run great at idle but once I hammered on it for a while followed by an immediate release of the throttle, the skis exhaust would sound bubbly and would have a terrible throttle response. Once I chomped the throttle on and off a handful of times it would seem to clear it out, but some times takes longer than others.
I have read a few articles on carb tuning for the 701 engine but I am still very fuzzy on it - I am having a difficult time telling whether it is running rich or lean on the hi's. I also read that it could be the result of a bad waterbox causing the hesitation and the need to blow out the water rushed back inside of it. My goal is to get this thing running as reliable and best tuned as possible (as any builder). I just do not want to hurt my fresh engine due to lack of tuning skills.
I was told to set the Hi at 1.5 turns out, Lo at 1, and start from there. How do the hi's and lo's work? Is it the more you turn them out the richer it becomes or vice versa? Anyone have any experience on this issue? Thanks a ton for any advice.
JT
The engine is as follows:
705 bore on a 61x cylinder block
ADA 35 cc head (~180 PSI)
Factory Mod B-pipe
Stock 38 62t carbs
- Needle/seat 1.5
- Hi 135
- Lo 75
Unfortunately I don't have anything to test pop off pressure of the carbs so tuning is a real pain. Recently when I took the ski out it seemed to run great at idle but once I hammered on it for a while followed by an immediate release of the throttle, the skis exhaust would sound bubbly and would have a terrible throttle response. Once I chomped the throttle on and off a handful of times it would seem to clear it out, but some times takes longer than others.
I have read a few articles on carb tuning for the 701 engine but I am still very fuzzy on it - I am having a difficult time telling whether it is running rich or lean on the hi's. I also read that it could be the result of a bad waterbox causing the hesitation and the need to blow out the water rushed back inside of it. My goal is to get this thing running as reliable and best tuned as possible (as any builder). I just do not want to hurt my fresh engine due to lack of tuning skills.
I was told to set the Hi at 1.5 turns out, Lo at 1, and start from there. How do the hi's and lo's work? Is it the more you turn them out the richer it becomes or vice versa? Anyone have any experience on this issue? Thanks a ton for any advice.
JT
