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Old 05-11-2010, 07:08 PM   #1
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Hi I have a novarossi p5xl I changed the crankshaft to a putty filled one, new ceramic bearings front and rear no slop in rod I s it normal to take like 25 to 30 seconds to idle down from a high or low speed run It then idles fine It also has good smoke coming out could it be a air leek?thanks.Tim
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Old 05-11-2010, 07:18 PM   #2
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Hi I have a novarossi p5xl I changed the crankshaft to a putty filled one, new ceramic bearings front and rear no slop in rod I s it normal to take like 25 to 30 seconds to idle down from a high or low speed run It then idles fine It also has good smoke coming out could it be a air leek?thanks.Tim
I had this problem over the weekend and it turned out to be a dirty air filter cause the LSN to be rich.. If your air filter is realtively clean, mine was NASTY NASTY, thne your bottom end is a touch rich.. Lean it out an hour at a time, until it drops right to idle with out any further dropping, after being hard on the throttle.. Make sure to keep adjusting the idle speed down too..
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Old 05-11-2010, 07:20 PM   #3
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Trying richening the bottom a little bit as a lean bottom causes that problem. By the sounds of things it is an air leak. If it is still doing it after richening the bottom, replace the fuel line and fuel tank. If it is STILL going it, take the backplate and carb off and seal them. Then make sure the rear engine gasket and pipe gasket isn't damaged.
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Old 05-11-2010, 07:20 PM   #4
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sounds like your low speed could be a little on the lean side. i would also double check your idle speed screw setting. that would be my first course of action.
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Old 05-11-2010, 07:28 PM   #5
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sounds like your low speed could be a little on the lean side. i would also double check your idle speed screw setting. that would be my first course of action.


whould a to small of a gap on the idle, cause it to drop like that yea it could be a leak but i also think a rich top, end and a leaner lsn whould do that also.
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Old 05-11-2010, 07:30 PM   #6
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If you can pinch the fuel like and it doesn't shut off after 6-7 seconds, your bottom end is too lean. That is what causes it to "run-on" after giving it throttle.
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Old 05-11-2010, 07:33 PM   #7
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If you can pinch the fuel like and it doesn't shut off after 6-7 seconds, your bottom end is too lean. That is what causes it to "run-on" after giving it throttle.


really i though if you pinch the fuel line, and it shuts off right away than its too lean but everyone has a diffrent method. and also no smoke coming out of the pipe .
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Old 05-11-2010, 07:35 PM   #8
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really i though if you pinch the fuel line, and it shuts off right away than its too lean but everyone has a diffrent method. and also no smoke coming out of the pipe .
Personally, I just close my eyes and turn needles into I get it right
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Old 05-11-2010, 07:39 PM   #9
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Personally, I just close my eyes and turn needles into I get it right


lol im not the best tuner but i know, when the lsn is a bit rich and theres no punch.
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Old 05-11-2010, 07:42 PM   #10
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Agreed, a run-on is caused by a lean bottom end. If it is running on after a high speed runs, the bottom end is most likely too lean. Richening the bottom end will fix this issue.

If it is just giving you a "two stage idle" it is possible that the bottom end is in fact too rich and the idle gap too large causing a false idle. In this situation the engine will come down to one idle and after the case loads up from the rich bottom end it will come down to a second idle. Leaning the bottom out and lowering the idle will fix this problem.

My suggestion if you are new to tuning is to go back to factory settings and re-tune from there. It can get a bit confusing to work through the odd issues like this one if you don't have a good set of base line settings.
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Old 05-11-2010, 07:43 PM   #11
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Make sure you didn't rip the oring in the block where the carb seals on the bottom , trust me , it will play havoc with your tuning . If the idle is a tingy idle it is too lean , if it is a consistant idle then it is a bit rich .

The pinch test should yield an idle up in 2-3 seconds and die out in 5-8 seconds

Tuning the low end on an engine is the real art of carburetor tuning

And another thing , it is sooooo hard to tune an engine third hand over the pc
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Old 05-11-2010, 07:45 PM   #12
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Agreed, a run-on is caused by a lean bottom end. If it is running on after a high speed runs, the bottom end is most likely too lean. Richening the bottom end will fix this issue.

If it is just giving you a "two stage idle" it is possible that the bottom end is in fact too rich and the idle gap too large causing a false idle. In this situation the engine will come down to one idle and after the case loads up from the rich bottom end it will come down to a second idle. Leaning the bottom out and lowering the idle will fix this problem.

My suggestion if you are new to tuning is to go back to factory settings and re-tune from there. It can get a bit confusing to work through the odd issues like this one if you don't have a good set of base line settings.
Why don't you tune my motors then?!
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Old 05-11-2010, 07:46 PM   #13
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Why don't you tune my motors then?!

you have learn your self man thats what im trying to do.
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Old 05-11-2010, 07:46 PM   #14
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Why don't you tune my motors then?!
Hahaha.
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Old 05-11-2010, 07:48 PM   #15
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you have learn your self man thats what im trying to do.
CJ knows more about tuning engines than he is letting on.
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