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Old 12-26-2008, 11:19 PM   #81
olddealer
Adventurer
 
Joined: Dec 2008
Oddometer: 12
idle problems

Hello again adrenalin... The advancer is the cam that opens the points. If you take the point cover off and grab the points cam between your thumb and first finger you should be able to turn it about 15 degrees ( I don't remember exactly what the advance is) and when you release it it should return under spring pressure to it's original position. Also in it's original position it shouldn't be loose (maybe a degree or so only). You have to check this with the engine off because with your reving problem a timing light would show full advance as soon as the engine revs and that is what it's supposed to do anyway. I should add that if you could somehow manually advance the timing at idle the rpm would go up just because of the advance and that's why I suspect the springs on the advancer are stretched. Did I mention the advancer is a centripital device with springs and weights and the weights move out with increasing rpm and that action turns the cam lobe more advanced. I always figured that the reason the springs stretched was because when changing points some inquireing mind would take the thing apart and that's when they would stretch. By the way adrenlin there may be another answer to your problem not related to this but it's easy to check and it can cause eratic rpm's. I think you should double check your carb slides also. If you pull up on the throttle cable on one carb at a time and release it it should make a nice click when you let go of the cable jacket. Come to think of it check the carb synchronization. Pull the air cleaners on both carbs, look in the throats from the back and make sure they open at the same time, the same amount and close together. Did you check compression on both cyclinders? Oh OH OH... Last resort pull both mufflers off and see if things improve. When checking compression make sure choke is open and hold throttle full open (should be3 about 175# per cylinder. Test it cold and then test it again hot. If compression goes down check tappets, especially intake tappet. It's been a long long time and my 160 was bought as a basket case so I can't check any of these things I am telling you so if someone has better recommendations, specs etc. please chime in ,,I won't be offended.. Dave
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