Engine sputter after kill switch
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Road Captain
Joined: Nov 2007
Posts: 577
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From: Lake Tenkiller, Oklahoma
Engine sputter after kill switch
I have had this happen three times now. Not consecutively, but under the same circumstances.
After no-problems, highway rides @ 55-65mph, I slowed down to enter the town, not a long trip (maybe a mile @35mph) to the post office. Then a first gear ride thru the parking lot, back in - hit the kill switch, and the engine sputters/shutters before it quits.
As I said, this happened at random times, not all on the same ride, or even in the same week. Could it be the cooler temp riding? Should I be concerned?
After no-problems, highway rides @ 55-65mph, I slowed down to enter the town, not a long trip (maybe a mile @35mph) to the post office. Then a first gear ride thru the parking lot, back in - hit the kill switch, and the engine sputters/shutters before it quits.
As I said, this happened at random times, not all on the same ride, or even in the same week. Could it be the cooler temp riding? Should I be concerned?
Road Master
Joined: Sep 2007
Posts: 1,019
Likes: 7
From: Chester County, PA
RE: Engine sputter after kill switch
ORIGINAL: Amzie
I have had this happen three times now. Not consecutively, but under the same circumstances.
After no-problems, highway rides @ 55-65mph, I slowed down to enter the town, not a long trip (maybe a mile @35mph) to the post office. Then a first gear ride thru the parking lot, back in - hit the kill switch, and the engine sputters/shutters before it quits.
As I said, this happened at random times, not all on the same ride, or even in the same week. Could it be the cooler temp riding? Should I be concerned?
I have had this happen three times now. Not consecutively, but under the same circumstances.
After no-problems, highway rides @ 55-65mph, I slowed down to enter the town, not a long trip (maybe a mile @35mph) to the post office. Then a first gear ride thru the parking lot, back in - hit the kill switch, and the engine sputters/shutters before it quits.
As I said, this happened at random times, not all on the same ride, or even in the same week. Could it be the cooler temp riding? Should I be concerned?
Likely causes in order:
1) excessive carbon deposits on the pistons and/or plugs (see running rich).
2) running rich and loading up the combustion chambers with unspent fuel.
3) valve timing is FUBARed thus not fully evacuating the cylinder on exhaust stroke, leaving unspent fuel/air.
Club Member
Joined: Feb 2007
Posts: 16,320
Likes: 306
From: Boynton Beach, FloriDuh
RE: Engine sputter after kill switch
Being that your bike is carbed, not EFI, I wouldn't worry about it too much if it only happens on a rare occasion. Sometimes with a carb. you can wind up with a bit to much fuel in the cylinder just as you shut the engine off and this can be the result. In addition to what was mentioned above, low octane fuel can also cause the problem.
Mine has done it about 3 times in the last year, 15,000 miles during that time, and in both hot and cold weather. I know I don't have carbon buildup and that my A/F ratio is correct. Sometimes this chit just happens, these engines, especially carbed, just aren't sophisticated, precision machines.
Mine has done it about 3 times in the last year, 15,000 miles during that time, and in both hot and cold weather. I know I don't have carbon buildup and that my A/F ratio is correct. Sometimes this chit just happens, these engines, especially carbed, just aren't sophisticated, precision machines.
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Road Captain
Joined: Nov 2007
Posts: 577
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From: Lake Tenkiller, Oklahoma
RE: Engine sputter after kill switch
Thank you everyone for the run down of what to look for.
CHarley, you made feel much better about it, as it only does it at random.
It has just been (with in 500 miles) rejetted for the new pipes ... so I assumed the HD mechanic set it all up right.
Rode it to the bank today (man you can tell they are NOT [sm=wtf.gif] used to a Harley coming thru the drive thru!), 60 miles round trip w/stops along the way, and it behaved perfectly.
I would like to ask you though, ... is it safe to use a gas additive like you would on a cage to clean the engine? If so, what would be your reccomendations? I always use premium, but I know by the cage, some stations are better than others on the gas. I switched stations because I was only getting 21-23mpg in the cage(and it ran awful) - and yesterday I hit 27mpg, which is much closer to what it should be, and I use additives to clean up the bad gas after taste in it.
oh, btw, I have not used the key to turn it off.
CHarley, you made feel much better about it, as it only does it at random.
It has just been (with in 500 miles) rejetted for the new pipes ... so I assumed the HD mechanic set it all up right.
Rode it to the bank today (man you can tell they are NOT [sm=wtf.gif] used to a Harley coming thru the drive thru!), 60 miles round trip w/stops along the way, and it behaved perfectly.
I would like to ask you though, ... is it safe to use a gas additive like you would on a cage to clean the engine? If so, what would be your reccomendations? I always use premium, but I know by the cage, some stations are better than others on the gas. I switched stations because I was only getting 21-23mpg in the cage(and it ran awful) - and yesterday I hit 27mpg, which is much closer to what it should be, and I use additives to clean up the bad gas after taste in it.
oh, btw, I have not used the key to turn it off.
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Outstanding HDF Member
Joined: Aug 2007
Posts: 2,225
Likes: 4
From: fegfsg
RE: Engine sputter after kill switch
ORIGINAL: Amzie
Thank you everyone for the run down of what to look for.
CHarley, you made feel much better about it, as it only does it at random.
It has just been (with in 500 miles) rejetted for the new pipes ... so I assumed the HD mechanic set it all up right.
Rode it to the bank today (man you can tell they are NOT [sm=wtf.gif] used to a Harley coming thru the drive thru!), 60 miles round trip w/stops along the way, and it behaved perfectly.
I would like to ask you though, ... is it safe to use a gas additive like you would on a cage to clean the engine? If so, what would be your reccomendations? I always use premium, but I know by the cage, some stations are better than others on the gas. I switched stations because I was only getting 21-23mpg in the cage(and it ran awful) - and esterday I hit 27mpg, which is much closer to what it should be, and I usey additives to clean up the bad gas after taste in it.
oh, btw, I have not used the key to turn it off.
Thank you everyone for the run down of what to look for.
CHarley, you made feel much better about it, as it only does it at random.
It has just been (with in 500 miles) rejetted for the new pipes ... so I assumed the HD mechanic set it all up right.
Rode it to the bank today (man you can tell they are NOT [sm=wtf.gif] used to a Harley coming thru the drive thru!), 60 miles round trip w/stops along the way, and it behaved perfectly.
I would like to ask you though, ... is it safe to use a gas additive like you would on a cage to clean the engine? If so, what would be your reccomendations? I always use premium, but I know by the cage, some stations are better than others on the gas. I switched stations because I was only getting 21-23mpg in the cage(and it ran awful) - and esterday I hit 27mpg, which is much closer to what it should be, and I usey additives to clean up the bad gas after taste in it.
oh, btw, I have not used the key to turn it off.
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Road Master
Joined: Dec 2007
Posts: 1,125
Likes: 22
From: Phoenix, AZ
RE: Engine sputter after kill switch
ORIGINAL: chornbe
It's called "dieseling" - so called for its tendency to ignite existing air/fuel mixture without spark.
Likely causes in order:
1) excessive carbon deposits on the pistons and/or plugs (see running rich).
2) running rich and loading up the combustion chambers with unspent fuel.
3) valve timing is FUBARed thus not fully evacuating the cylinder on exhaust stroke, leaving unspent fuel/air.
It's called "dieseling" - so called for its tendency to ignite existing air/fuel mixture without spark.
Likely causes in order:
1) excessive carbon deposits on the pistons and/or plugs (see running rich).
2) running rich and loading up the combustion chambers with unspent fuel.
3) valve timing is FUBARed thus not fully evacuating the cylinder on exhaust stroke, leaving unspent fuel/air.
It has happened with air temps of 40*F to 80*F. It has happened after short rides and long rides. Not yet twice in one day. Twice in one week once. But less than once a month.
Being a high-mileage sportster I woudld go with all three possibilities and others combined.
It has also happened using either the key or the kill switch, not that the switch makes a difference according to the wiring diagram.
ps. A few years ago I lived in ME and rode along the coast alot. At temps under 32*F the carb would freeze keeping the throtle open. Now I live inland in NH and this winter my carb has not yet frozen. Could be the lack of MBTE in the fuel, could be the little difference in humidity that 70 miles makes? I'm not worried about the dieseling because it occurs soo rarely.