Brian and I have a difference of opinion concerning the use of chokes. Where it concersn automotive engines and carbs made for them they have chokes, usually electric automatic and are designed for their use. I would leave it though you may want to convert it to manual if it is not already that way. I ahve a choke on my Zenith and love it. It makes it start just like my Camaro and does not exhibit the hard start problems that the Lycs have when cold. The purpose of the choke is to restrict the volume of air to raise the fuel air mixture sufficiently for engine startup AND warmup. I have a choke on my 2001 Yamaha V-Star as well and would hate to try and start it without a choke. Primer systems are ok, but I do not like them because a direct injection of raw fuel into a cylinder at startup, the very time when only left over oil is inside the engine , can rinse away precious lubrication you need for starting protection. Remember, auto engine conversions do NOT have the excess clearances of internal components that our distant cousins of the aircraft engine breed have. This can cause alot of excessive scoring during cold start and warmup. Even the Lycomings that are in the Cessnas and Pipers I train in alot that have accelerator pumps built into the carbs start better by pumping the throttle once or twice just like the Camaro at home, instead of using the primer. Come to think of it, I never use the primer on any certified engine except the 152 when it is cold, and mine has a choke. Also, my advice would be to set the carb at your altitude, and then if you find you need to lean the mix, add an adjustable bleed port that use filtered air into the intake just after the carb so that the entire engine is effected the same instead of trying to adjust the mixture needle on the carb. This has been done reliably for years in cars by adding bleeds to the carbs and recirculation valves with different sizesd orifices to improve emissions by adding air or leaning the mix, same result.
Colin & Bev Rainey KR2(td) N96TA Sanford, FL [email protected] http://kr-builder.org/Colin/index.html
