smallplanes

My Feedback: (3)

I have a shindaiwa 21cc motor on a super stick 60 and i have a problem. I had the motor running great the other day on the plane and i flu it but it was a little rich. So i landed and richin it up but it was to late to try it again. The next day i tried flying it but i had the radio on the wrong model,and time i took off it rolled over and hit the ground. I fixed the plane and tried it the next day and now if i have it over half throttle it is missing and cutting back the whole time i'm flying it. I took the carb apart and cleaned it and it still does the same thing. I checked the timing and its about 27degs. Can someone tell me what they think might be wrong with it? O yes i have EI on it that i wired up from parts that i got off web. Thanks for any help.

Thanks
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airbr

My Feedback: (4)

My opinion to you problem is a rich mixture, you may need some help to tune it or if you could tie it down that would be good. At full throttle lean out the high end till it cuts back on rpm.
When it does richin just until you regain that rpm not anymore. Go to idle and check your transition if it spits or give a fourstrock sound especially at half throttle you will need to lean out the low end, keep doing that until you reach your disired performance, carefull not to lean the low end too much cause it will burn up.

Good luck.

smallplanes

My Feedback: (3)

I did every thing you said and it still cuts back at above half throttle. I put a new plug in it i mixed up some Amsoil pro 80:1 and it still does it. I also bought a WA 197 A carb (same as on G23) and it does the same thing. I have the plane in a tail hook on the ground and have been adjusting the carb ,the leaner i get it the worse it gets(cutting back that is) the richer i get it it start to clear up but it cuts the rpms so much it has no power. The thing is it was running great the other day. I'm not sure.

Thanks
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aero nut

Check the charge of your EI battery pack if its not fully charged it may start misfiring rich like, other check the timing with the engine running by loosening the clamp enough for you to move the sensor back and forth until you have a nice running engine, just my tohught.

airbr

My Feedback: (4)

Yeah That would be my next guess, but also a 80:1 mix is on the high side. It should not need anymore than 50:1 and that is still on the heavy side. The difference being the engine runs alot cooler for aircraft application so a high oil content is bad. Also open the gap on your plug about .005 more than what you have it will give a better spark especially if you are using the CDI type ignition. My only other guess would be a broken ring.

smallplanes

My Feedback: (3)

aero nut I charged the battery thinking the same thing you said, battery is fully charged and it still missing at high rpm. Well the way i have my sensor i'm not sure if i can move it with it running but i might try that also.


browng300 I have it at 80:1 with Amsoil sabre 100:1 mix oil so that is less oil than at a 50:1 mix. Yes i do have CDI on it and i will try opening up the spark gap like you said. Well this motor is brand new do you think its possible that the ring could be broken? I had Lawn Boy oil mixed 32:1 in it and it ran the same as the amsoil.

Well not sure when i can run it again its raining here and suppose to rain for a few more days. I'll let you know how it does.

Thanks guys
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smallplanes

My Feedback: (3)

I checked ring and its not broken. I will run it when i can.


Thanks
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airbr

My Feedback: (4)

Check your crank case pulse hole to carb and make sure it is doing what it is suppose to.

Antique

My Feedback: (4)

High voltage coil going ?

RunningMan

Check that your tank clunk is hanging in the back of the tank. Could have been knocked forward and the line is kinked and restricting flow.

Steve

smallplanes

My Feedback: (3)

Antique This is a new coil from CH i think it's ok but you never know.

Runningman You have a point it might be the clunk i have not checked that.

browng300 The hole is open to the hole on the carb. How do you mean to check to see if its doing what it is suppose too?

Do you guys think a velocity stack will make any difference? I made one last night but i have not tried it. What about the vent on the pump of the carb, do you think that could be the problem? The vent is facing the prop thats how it was facing off the weedeater. If its not one of these things that you guys says it is it must be the ignition. Thats the only other thing i can think of. I going to check tank. O yes how do you know if a coil is going bad? The motor runs great up to a little past half throttle. Thanks for all the help guys i will keep at it until i get it.

Thanks
smallplanes

smallplanes

My Feedback: (3)

Well i got it fixed and i can not believe what it was. It was the plug, i put 3 brand new plugs in it and it done the same thing(still missing). I ordered the plugs from CH and they where NGK BPMR6F taper seat plugs. I had a plug in my box that fit a G23(BMR7A) it was not a taper seat plug it had the washer on it so i put it in it to try it because i've tried everything else. It ran great with this plug i flu it a few times and it done great. I got 7800 rpms out of it with a 16-6 apc prop and it has stock carb. I'm going to lean it down a little more to see if i can get a little more out of it. I was so happy that it ran i was scared to lean it to much but i will try a little more. I would not have every thought it would run better with this kind of plug in it but it does. When i had it in the tail hook i could put my hand in front of the vent on the carb and it would gain a lot more rpms. So i welded a steel clevis to the vent hole then cut off the two legs of it and put a piece of fuel tubing over it, then i tie straped it to the velocity stack that i made for it and that worked good. I also put the timing on 30degs. This motor runs great now i am so glad it got the problem fixed. Can someone tell me why they think this plug made that much difference over the other plug?

Thanks for all the help
smallplanes