Moderator: SteveM
RC_Flyer wrote:Thanks for the response. I understand that it would be possible to jam the low speed needle into the spray bar end and distort it (bell mouth). I expect this could happen when owners tighten the throttle arm retaining nut without holding the throttle barrel and jam the low speed needle into the spray bar. But I seem to have the opposite problem and after more break in time and tweaking it’s running much better.
I have three new RJL K.61s that have never been disassembled or messed with. I like to have spare backups for each type of engine I have! The down side of this is that often the warranty expires before they all can be used.
Two of them have throttle barrels that can stop before they can close all the way because the low speed needle bottoms out in the end of the spray bar. The solution is to turn the low speed needle out so it is just past the end of the throttle arm retaining nut (about .005 or less). I’ve only started one of these engines and I find the low speed setting is very sensitive, a very small amount of movement of the needle can go from too rich to too lean. There is a very fine line between having the throttle barrel close all the way for throttle kill, getting the low end lean enough and not having the low speed needle bottom out in the spray bar. But it is possible to have the barrel close all the way and be able to have the engine low end too lean so I know with a little adjusting it can be done.
With the third and newest of the three new engines, the throttle barrel will go way past the fully closed position with the low speed needle flush with the throttle arm retain nut? All of the engines came in the Blue RJL boxs. All of the carbs look identical from the outside. Here’s a picture of all three engines http://image.rcuniverse.com/forum/upfil ... d51526.jpg and the newest http://image.rcuniverse.com/forum/upfil ... j23208.jpg and the older ones http://image.rcuniverse.com/forum/upfil ... v67278.jpg and http://image.rcuniverse.com/forum/upfil ... r40678.jpg and http://image.rcuniverse.com/forum/upfil ... x68531.jpg
I like the K.61s very much and the carb design looks very, very good so I’m probably missing something simple. I have other engines with similar type carb function like my Webra 61s but have never run into a problem with the low speed needles bottoming out in the spray bar.
Any insight you can provide on how the low speed needle and throttle barrel movement should work would be greatly appreciated.
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