3W 80 XI
 

I have a 3W 80 XI fairley new that when brought down to idle it goes up about a 1,000 RPMs and then back down to a normal idle. This engine ran perfect when I last flew it. I've done everything I know what to do I even made a gasket were there isn't one and still the same. Anyone with any help will be appreciated.

Thanks Soinks

RE: 3W 80 XI
 

Hasen't anyone heard of or experienced a problem like this. I thought sure that someone would have chimed in and tell me my problem. I hope someone will see this and help me soon, can't fly it like this it makes it very tricky to land.

Thanks Soinks

RE: 3W 80 XI
 

Soinks, I had a throttle servo that had a worn feedback pot. It gave me an erratic idle. Try changing your servo. Dan.

RE: 3W 80 XI
 

Thanks for the response but I disconnected the servo and used just my hand and the same thing happened but once again thanks for your advice.

Soinks

RE: 3W 80 XI
 

If changing the idle carb mixture adjustment a bit one way or the other does not effect the problem maybe the ignition
is not working right at low speed, try swapping it out with another unit if possible.

RE: 3W 80 XI
 

this has me thinking the idle stop screw is still in place and may be the issue.
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RE: 3W 80 XI
 

i had a similar issue with my 80.... i slapped a walbro on it and it improved.... i got mine from DA..... the same carb they use on their 85

RE: 3W 80 XI
 

i had a similar issue with my 80.... i slapped a walbro on it and it improved.... i got mine from DA..... the same carb they use on their 85 (WJ-71)

RE: 3W 80 XI
 

Hi Speedracerntrixie
I don't understand how the idle stop screw could cause this problem but I would like to hear how it could . Please let me know when u get a chance.

Thanks Soinks

RE: 3W 80 XI
 

Worth a try for $50. Dan.
http://search.cartserver.com/search/...WJ-71&go=GO%21

RE: 3W 80 XI
 

most guys just get rid of the idle stop screw. If you are using it to adjust your idle speed the servo is constantly pulling against it. Add in the vibration from the engine and the servo is being worked really hard. This will cause the servo IC to heat up and the servo end points will drift. Most of the time I have seen the use of the idle stop screw result in stripped servo gears. It could also be that the slight side to side play that all carbs have is preventing it from falling on the same spot each time. I would suggest 2 things at this point. First get rid of the idle stop screw and adjust idle via TX. This will also allow you to shut the engine down with the TX. Second, pull the carb and make sure the throttle butterfly screw is tight.
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RE: 3W 80 XI
 

MetallicaJunkie
did you have to do much refitting with the Walbro? like the throttle hook up gas lines or anything else?

Thanks Soinks

RE: 3W 80 XI
 

i honestly dont remember...if you have easy access to the carb it should be a piece of cake

RE: 3W 80 XI
 

I just happen to have a new DA 100 L I wonder if that carburetor will work

RE: 3W 80 XI
 

I just happen to have a new DA 100 L I wonder if that carburetor will work

RE: 3W 80 XI
 

Your problem sounds like a Tillotson phenomenon.
I had a 3W 150 stock carb that did the same thing even after a carb rebuild.
Went away when I switched to another type of carb.
Walbro seems to be good answer for the Tillotson phenomenon most of the time.

RE: 3W 80 XI
 

Kmtranmd. Thanks for that advice I have a new DA 100 L that has that carb I'll try that. Do u remember any needle settings or should I just open them about one turn open and go from there. Let me know if u think of anything that u did on yours please.

Thanks Soinks

RE: 3W 80 XI
 

Kmtranmd. Thanks for that advice I have a new DA 100 L that has that carb I'll try that. Do u remember any needle settings or should I just open them about one turn open and go from there. Let me know if u think of anything that u did on yours please.

Thanks Soinks

RE: 3W 80 XI
 

Hey there,
I have a 3w80 that is exhibiting a few carb type problems and would consider the walboro carb solution if it works out for you. Let us know how it goes!
Thanks

RE: 3W 80 XI
 

Here is a video of a 75 having the same issue as you are. The video is after the swap.
http://www.youtube.com/watch?v=H5RxK5j3gSo

Well I finally did it and I believe that the problem went away. It runs very smooth at low rpms I think the needles are about 1-1/4 to 1-1/2 out. Let me know if this helps.

Soinks