sportster 45

[cheetah1]

Older sportster 45 idles rich. Adjusting per instructions doesn't get idle lean enough. High end seems OK. Removed and cleaned needle valve assy, didn't help. Replaced needle valve assy, no help. Removed and cleaned barrel assy, no help. Using idle bar glow plug helps but not enough. Engine is slow speeding up and smokes when throttle is opened. I have tried 5 glow plugs, 10% & 15% fuel. Idle can only be obtained about 3500 RPM. Ship tries to float and have to cut throttle to land. I am out of ideas. Not much time on engine for wear to be a problem.

[MECOA]

Sorry but you have to wait sometimes for FREE tech help. This froum is usually checked twice a week.

Your answer is at the bottom of this page.
http://www.mecoa.com/faq/carb/mixdisk/mixdisk.htm

[cheetah1]

I have tried everthing on the page you suggested and it still won't idle low enough. I even replaced the whole needle valve assy from an other 45 I have. The idle is rough and cannot be slowed down enugh to land a ship without dying. I have checked everything from the muffler tap to the gas line and tank. The disc gives a small amount of adjustment right around neutral and that is all. It seems like I need just a little bit more adjustment. The only other thing could be something causing the egine to run rough at idle besides the idle adjustment. I have tried all kinds of glow plugs.

[MECOA]

If you have trouble with a rich idle and are unable to adjust it properly and you have checked all of the above, The inner tube of the mixture disk (where the slot and hole are in the picture to the left) may have excessive wear with the mating tube inside the barrel. The is a very close and precise fit. If it is loose it will not meter the fuel properly at idle. Kinda like a leaky faucet. At this point the carb should probably be replaced or at minimum the mixture disk and barrel replaced.

A good fit must also be maintained between the barrel and body. If this is worn, you will have air leakage and not be ably to get consistent idle or have the ability to shut the engine down when carb is closed.

If you can not obtain a consistent mixture or a rich enough high speed mixture check inside the spray bar. Many times something is plugging up the metering slot that controls the fuel flow for idle and midrange. Symptoms are not being able to obtain idle settings, not getting a rich enough high speed setting, and erratic settings.

[cheetah1]

Thanks for the help. I can try the carb from my other 45 sportster. I'll see what happens. The thought came to me also when I ran out of other possibilities. Thanks again. George