46fx Sagging in Transition. Thoughts?
01-17-2008 | 09:45 AM
#1
Thread Starter
Senior Member
46fx Sagging in Transition. Thoughts?
At idle, when I apply throttle quickly, the engine sags noticeably. It doesn`t sputter and burble like you ordinarily associate with a rich low end, it justs sags, sometimes to the point of cutting out. I`ve been working from the assumption that it`s loading up at idle because when I run it at open throttle ( runs fine )and cut it back, and then quickly open the throttle again, it transitions fine. Maybe my assumption`s off base (?). I`ve been leaning out the low end, but so far without much improvement ( some though ). Any thoughts would be appreciated. Maybe I just haven`t hit the sweet spot on the low end? Thanks.
01-17-2008 | 10:36 AM
#5
Senior Member
RE: 46fx Sagging in Transition. Thoughts?
ORIGINAL: TideFlyer
At idle, when I apply throttle quickly, the engine sags noticeably. It doesn`t sputter and burble like you ordinarily associate with a rich low end, it justs sags, sometimes to the point of cutting out. I`ve been working from the assumption that it`s loading up at idle because when I run it at open throttle ( runs fine )and cut it back, and then quickly open the throttle again, it transitions fine. Maybe my assumption`s off base (?). I`ve been leaning out the low end, but so far without much improvement ( some though ). Any thoughts would be appreciated. Maybe I just haven`t hit the sweet spot on the low end? Thanks.
At idle, when I apply throttle quickly, the engine sags noticeably. It doesn`t sputter and burble like you ordinarily associate with a rich low end, it justs sags, sometimes to the point of cutting out. I`ve been working from the assumption that it`s loading up at idle because when I run it at open throttle ( runs fine )and cut it back, and then quickly open the throttle again, it transitions fine. Maybe my assumption`s off base (?). I`ve been leaning out the low end, but so far without much improvement ( some though ). Any thoughts would be appreciated. Maybe I just haven`t hit the sweet spot on the low end? Thanks.
You don't mention using the pinch test. Try it.
With a warmed up engine, set the highspeed needle.
Let it idle awhile. Say 20-30seconds.
Pinch the fuel hose close to the carb. Pinch it completely closed.
It'll take a couple of seconds to run out of fuel, but when it does:
If it speeds up before shutting off the lowspeed needle was too rich and the optimum setting would have been leaner.
If it simply dies, it was probably too lean. It could also have been very close to perfect. Give it a very fine tweak richer and try again.
Pinch test is one of the best tests we got.
01-17-2008 | 11:04 AM
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From: Poland,
OH
RE: 46fx Sagging in Transition. Thoughts?
ORIGINAL: da Rock
You don't mention using the pinch test. Try it.
With a warmed up engine, set the highspeed needle.
Let it idle awhile. Say 20-30seconds.
Pinch the fuel hose close to the carb. Pinch it completely closed.
It'll take a couple of seconds to run out of fuel, but when it does:
If it speeds up before shutting off the lowspeed needle was too rich and the optimum setting would have been leaner.
If it simply dies, it was probably too lean. It could also have been very close to perfect. Give it a very fine tweak richer and try again.
Pinch test is one of the best tests we got.
ORIGINAL: TideFlyer
At idle, when I apply throttle quickly, the engine sags noticeably. It doesn`t sputter and burble like you ordinarily associate with a rich low end, it justs sags, sometimes to the point of cutting out. I`ve been working from the assumption that it`s loading up at idle because when I run it at open throttle ( runs fine )and cut it back, and then quickly open the throttle again, it transitions fine. Maybe my assumption`s off base (?). I`ve been leaning out the low end, but so far without much improvement ( some though ). Any thoughts would be appreciated. Maybe I just haven`t hit the sweet spot on the low end? Thanks.
At idle, when I apply throttle quickly, the engine sags noticeably. It doesn`t sputter and burble like you ordinarily associate with a rich low end, it justs sags, sometimes to the point of cutting out. I`ve been working from the assumption that it`s loading up at idle because when I run it at open throttle ( runs fine )and cut it back, and then quickly open the throttle again, it transitions fine. Maybe my assumption`s off base (?). I`ve been leaning out the low end, but so far without much improvement ( some though ). Any thoughts would be appreciated. Maybe I just haven`t hit the sweet spot on the low end? Thanks.
You don't mention using the pinch test. Try it.
With a warmed up engine, set the highspeed needle.
Let it idle awhile. Say 20-30seconds.
Pinch the fuel hose close to the carb. Pinch it completely closed.
It'll take a couple of seconds to run out of fuel, but when it does:
If it speeds up before shutting off the lowspeed needle was too rich and the optimum setting would have been leaner.
If it simply dies, it was probably too lean. It could also have been very close to perfect. Give it a very fine tweak richer and try again.
Pinch test is one of the best tests we got.
