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OSFxi 46


Old 02-05-2013, 07:48 AM
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Default OSFxi 46

I have a used but new to me OSMax 46 Fxi engine that I bought at a swap meet last year. It has new bearings and appears to be brand new other than that. My problem is it won't start and run. When throttle is opened a little from fast idle start up position a lot fuel blows out of carb. I removed muffler pressure and closed main needle allmost all the way and it started weakly and would not speed up, finally stopping even with the ignitor still connected. Do I need a new carb?
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Old 02-06-2013, 07:12 AM
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Default RE: OSFxi 46

First off, make sure you have a new glow plug and are using good-quality, fresh fuel. Make sure your fuel system in clean and has no leaks anywhere.

To begin, set the idle mixture to be very rich. Make sure the high-speed needle is opened about 2-1/2 to 3 turns out from closed. Start the engine at part throttle and then advance it to full. It should be running at full throttle, but very rich. Some fuel may spit out of the carb. That would be normal for a very-rich setting. With the battery still connected to the glow plug, start to lean the high-speed needle so that the engine will advance in RPM. It should do that.

If the engine has been properly broken-in, it should be able to accept the needle and allow you to lean it to peak RPM. If the engine will sustain running at peak RPM, then you can remove the glow plug battery and start to find the idle.

Gradually retard the throttle and adjust the low-speed mixture as needed to keep the engine running well. Since you know it started out very rich, you know it needs to be leaned. Lean a little at a time.......retard the throttle a bit, adjust as needed....do it again, and again until you find the idle RPM and mixture that will give you a good idle and a good acceleration. You can get a very low idle, but it may also not allow you to have a good acceleration. That's too low. Accept a bit more RPM so that you can have good throttle transition.
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