Mirror Image Carb? - Follow Up
Posted: Thu Dec 19, 2013 9:03 pm
I finally found some time and warm temperatures to get back on my nemesis, in trying to solve my engine issues. To bring new readers up to speed, here is a quick review of what I am fighting, and what I have done on this 1989 Elite E.
PROBLEM: When the motor is cold, it starts easily initially, but when holding the throttle at mid RPM for maybe 15 or 20 seconds (and the motor sounds good and strong with revving up quickly), it simply dies. Then it won't start again unless it is finger choked. Removing the carb drain plug, there is still ample fuel in the bowl. Checking the spark shows a good, solid spark, so I feel confident that ignition is not a problem. Letting the motor (and bistarter) cool down to ambient temperatures, the motor starts right up again. Mousewheels was kind enough to supply some pointers to check out, but all were futile. Tweaking the mixture and idle speed didn't make any changes at all when running, and the color of the exhaust didn't reveal a rich or lean condition either.
BRIEF HISTORY OF THE SCOOTER: This scooter was given to me by the original owner who bought it brand new in 1989. It is an Elite E, with the sb50p set up (I believe). It was parked outdoors, uncovered, and had not run for 8 to 10 years. He was NOT mechanically inclined, and it was a challenge for him to replace the spark plug. Therefor, it has not been tinkered with at all, until I became the new owner, that is. It is 100% factory original, with NO modifications made whatsoever. It was neglected, unfortunately, but I am attempting to resurrect it and get it running again like it once did.
WHAT HAS BEEN DONE SO FAR. As previously stated, it has good spark, and always has. The gas tank was removed, cleaned out with lacquer thinner, and compressed air. A new fuel shut off valve was installed, along with a new fuel line, and fuel strainer. A compression test shows between 115 and 120 PSI with a cold engine, and a closed throttle. The muffler had dirt dobbers build a mud nest inside the outlet to the point that no air could pass through it. That was cleaned out and free flows now with no restrictions. I have vatted the carb twice in carb cleaner, all passages blown through with compressed air, and no obstructions are to be found. I have pulled it apart at least a half a dozen times or more, and never found any "hidden" passages that could be blocked. The float level is set according to the service manual, and the needle and seat work freely like they should. The bistarter bench tests at 5.2 ohms, and travels approximately 0.125" when fully extended.
WHAT I HAVE FOUND AS OF TODAY: When the engine dies, I have removed the fuel bowl and measured the remaining fuel. There appears to be more than ample fuel to keep the engine running. The bistarter seems to be fully extended and to be blocking the passage that allows the carb to enrichen itself when cold. In other words, I believe it to be working like it should. I have done an extensive vacuum leak test on all surfaces that might be a source of a leak, and found none (spraying carb cleaner at all mating surfaces and vacuum connections). The carb has the original #68 jet that came with it new, which should be good for my area of about 1,000 feet in elevation. The previous owner said that he never had any issues with the scooter when he was using it, and it ran just fine and sounded good. It always started easily, even when hot. He just lost interested in it, and when his grandkids moved out of state, he parked it. I cannot tell any difference in the motor running if the air box is on or off, but it normally is off, as it is easier to finger choke the carb to get it to start up again and/or to keep it running.
MY QUESTION: I have been looking almost exclusively at the fuel system and carburetor as being the problem. I have fought a too rich condition, followed by a too lean condition when trying to restart it after it has ran for a brief moment. Could there be something out in left field that would cause this sporadic running, and/or something I have missed or not thought of? I ordered and received a new carb with the same physical dimensions, but the location of the bistarter is in the wrong place, preventing me from using it. Plus it is manufactured by somebody other than Honda, and the internal parts are not interchangeable at all. Mousewheels thinks it is for a Spree and not an Elite like I have. I'll take his word on that one, as he knows more about these things than I do.
CONCLUSION: My "gearhead" friends (who don't know too much about 2 stroke motors) are tired of me using them as a sounding board and asking questions that they cannot answer. I know it is nearly impossible to be an armchair quarterback on dilemmas like this, but I would appreciate any thoughts you might have that could possibly help me figure this beast out. When I accepted this scooter, I wanted a project to keep me busy. But it is rapidly turning into a career and an obsession with me. I have swung wrenches on various mechanical things for over 50 years, and have a mechanical engineering background to boot. But this little motor has me pulling what hair I have left out of my head in trying to get it to run like it should.
If you have any questions or any thoughts, please let me know. I'd hate to part the scooter out just because of something stupid that I am overlooking, and can't get the motor to run like it should. Does anybody have a good working carb that they can lend me to try and see if I am in the correct direction in solving this problem? We can talk more of you do. I'd gladly put up a deposit!
Thanks to those of you who took the time to read this, and are thinking about why the motor keeps stalling out. Oh, and I do NOT have the parking brake locked at all, as the rear wheel is free to spin when revving, in case you were wondering. Let's see if any of you can really make me have a very Merry Christmas or not! LOL
Andy
PROBLEM: When the motor is cold, it starts easily initially, but when holding the throttle at mid RPM for maybe 15 or 20 seconds (and the motor sounds good and strong with revving up quickly), it simply dies. Then it won't start again unless it is finger choked. Removing the carb drain plug, there is still ample fuel in the bowl. Checking the spark shows a good, solid spark, so I feel confident that ignition is not a problem. Letting the motor (and bistarter) cool down to ambient temperatures, the motor starts right up again. Mousewheels was kind enough to supply some pointers to check out, but all were futile. Tweaking the mixture and idle speed didn't make any changes at all when running, and the color of the exhaust didn't reveal a rich or lean condition either.
BRIEF HISTORY OF THE SCOOTER: This scooter was given to me by the original owner who bought it brand new in 1989. It is an Elite E, with the sb50p set up (I believe). It was parked outdoors, uncovered, and had not run for 8 to 10 years. He was NOT mechanically inclined, and it was a challenge for him to replace the spark plug. Therefor, it has not been tinkered with at all, until I became the new owner, that is. It is 100% factory original, with NO modifications made whatsoever. It was neglected, unfortunately, but I am attempting to resurrect it and get it running again like it once did.
WHAT HAS BEEN DONE SO FAR. As previously stated, it has good spark, and always has. The gas tank was removed, cleaned out with lacquer thinner, and compressed air. A new fuel shut off valve was installed, along with a new fuel line, and fuel strainer. A compression test shows between 115 and 120 PSI with a cold engine, and a closed throttle. The muffler had dirt dobbers build a mud nest inside the outlet to the point that no air could pass through it. That was cleaned out and free flows now with no restrictions. I have vatted the carb twice in carb cleaner, all passages blown through with compressed air, and no obstructions are to be found. I have pulled it apart at least a half a dozen times or more, and never found any "hidden" passages that could be blocked. The float level is set according to the service manual, and the needle and seat work freely like they should. The bistarter bench tests at 5.2 ohms, and travels approximately 0.125" when fully extended.
WHAT I HAVE FOUND AS OF TODAY: When the engine dies, I have removed the fuel bowl and measured the remaining fuel. There appears to be more than ample fuel to keep the engine running. The bistarter seems to be fully extended and to be blocking the passage that allows the carb to enrichen itself when cold. In other words, I believe it to be working like it should. I have done an extensive vacuum leak test on all surfaces that might be a source of a leak, and found none (spraying carb cleaner at all mating surfaces and vacuum connections). The carb has the original #68 jet that came with it new, which should be good for my area of about 1,000 feet in elevation. The previous owner said that he never had any issues with the scooter when he was using it, and it ran just fine and sounded good. It always started easily, even when hot. He just lost interested in it, and when his grandkids moved out of state, he parked it. I cannot tell any difference in the motor running if the air box is on or off, but it normally is off, as it is easier to finger choke the carb to get it to start up again and/or to keep it running.
MY QUESTION: I have been looking almost exclusively at the fuel system and carburetor as being the problem. I have fought a too rich condition, followed by a too lean condition when trying to restart it after it has ran for a brief moment. Could there be something out in left field that would cause this sporadic running, and/or something I have missed or not thought of? I ordered and received a new carb with the same physical dimensions, but the location of the bistarter is in the wrong place, preventing me from using it. Plus it is manufactured by somebody other than Honda, and the internal parts are not interchangeable at all. Mousewheels thinks it is for a Spree and not an Elite like I have. I'll take his word on that one, as he knows more about these things than I do.
CONCLUSION: My "gearhead" friends (who don't know too much about 2 stroke motors) are tired of me using them as a sounding board and asking questions that they cannot answer. I know it is nearly impossible to be an armchair quarterback on dilemmas like this, but I would appreciate any thoughts you might have that could possibly help me figure this beast out. When I accepted this scooter, I wanted a project to keep me busy. But it is rapidly turning into a career and an obsession with me. I have swung wrenches on various mechanical things for over 50 years, and have a mechanical engineering background to boot. But this little motor has me pulling what hair I have left out of my head in trying to get it to run like it should.
If you have any questions or any thoughts, please let me know. I'd hate to part the scooter out just because of something stupid that I am overlooking, and can't get the motor to run like it should. Does anybody have a good working carb that they can lend me to try and see if I am in the correct direction in solving this problem? We can talk more of you do. I'd gladly put up a deposit!
Thanks to those of you who took the time to read this, and are thinking about why the motor keeps stalling out. Oh, and I do NOT have the parking brake locked at all, as the rear wheel is free to spin when revving, in case you were wondering. Let's see if any of you can really make me have a very Merry Christmas or not! LOL
Andy