A tale of woe, bought a 75cc 3W 5 years ago and it's never finished a flight.
However I am awesome at dead sticks.
Well I am nearly at my wits end and have bought a DLE55 because it's got to be easier to tune.

I have tried searching but does anyone have a link to a how to tune 3Ws or Tillotson Carbs?
Some how I also ended up with a 3W55 and have pretty much the same problems but slightly different. Got help from all the local know it alls with no success, in fact the 55 blew its header apart like a bomb went off inside it. Know idea what went wrong with that but at $180aust for an muffler I thought stuff it and bought the new DLE55

I followed Zipps? tuning method for a Walbro and have managed to get the 75cc to pull 5200rpm and have been pulling back the throttle and adjusting the low range when it four strokes.

Just seems way to little full throttle rpm and when I snap the throttle back the idle drops down till it nearly stops (does in the air) and then slowly comes back up to 1800rpm. This is my main issue I suppose at the moment. What do I adjust to stop this slowing idle after snapping the throttle off.
I don't really want to have to have a 2200rpm idle to stop it shutting down. 2200rpm idle is not normal is it?

Currently the High needle is about a 1/16th off of 1 turn, but the low needle is only 1/8th over half open. These seem very wrong compared to the starting setting of 1 and 1. What are other peoples settings?

Appreciate any response, even laughs because I think this is taking the fun out of the sport for me ;-(

Cheers Justin.

I would start out at 1 & 1/2 out on the high end, and 1 & 1/4 on the low end. Shouldn't ever die!!!!!!!!!!!!! Should be dam close to ideal too. Start out way rich so you can achieve a rich baseline. I bet your running it lean and getting it hot where it's at now. Make sure your fuel lines are not sucking air anywhere.

What premix oil are you using and at what ratio??
Are you using super unleaded?
What prop are you using?
How does the spark plug look on the ceramic end that goes inside the enigne, and the arm over the ceramic? Clean Black, brown, tan, brand new, all white with tiny black specs, grey, oily?
How does it fly now until it dead sticks??? 5200 is not enough. You should get at least 6200 -6500.


I would recomend a 24x10, 24x12, 25or26x8 or Vess 25A/25B on the 3W75, and a 22x8, 22x10, 23x8 or Vess 22B/22C, 23A /23B on the 3W50

Thanks for the reply, I have been reading through the hundreds of pages but every single person has a different way to tune.
I have been flicking it all afternoon and my arm is about to fall off. ;-)
Started at your 1 & 1/2 and 1 & 1/4 got 4300 rpm max and 4 stroking, went in 1/8 turn on high no change, went in another no change went in another no change, went in another no change, went in to 1 got 5000 no 4 stroking, went in again got the same so left it because at 3/4s out on the high seems too far in.
Started on the low went in an 1/8th for stroking starts at 4200 as I pull it down from max. Went in 1/8 n change, and again no change, keep going until the 4stroking goes away and it starts to die on acceleration. went back out so it pulled cleanly from idle.
So I am back to just under 1 turn out of the high and just over 1/2 turn out on the low.
Engine revs to 5400 and nearly dies when I snap back to idle. Same as usual.

I going to give it one more chance because the DLE55cc turned up today and it's very pretty ;-)

3W synthetic at 50:1
98 octane premium unleaded
Unknown carbon fibre that I think is a 26 x 10, ran in on a wooden 24x10
Spark plug is black. Doesn't look at all pretty but every time I change them they go black.
Flys like it's gutless and makes burbling noises until it just stops. Not gradual, just bang stop.

Still can't find a how to tune tillotson carbie how to any where.

Cheers for your time.

Have you tried a diff ignition? black plug is way rich! something is retarding the spark either weak ignition or maybe bad timing?? maybe sommin else. Have you checked the timing?

Best fix is to order a DA I apologize for saying it but its true imo.

da ain't no better than any other and that isn't helping him at all,it sounds like the ign or the timing is off, the ign has an auto timing advance after 200 rpm it sounds like it isn't advancing, and i think i would ditch the 26 inch prop and stay with a 24 till it is ripping it then go back. call bobby at cactus aviation and he can help you sort it out

I guarantee if it was a DA it wouldn't take 5 years to get a full flight in; it would be sent in and repaired or replaced.

I have had a lot of exp with a lot of engines and i know atleast one thing for sure; If you like constant tinkering and fixing an engine you need a 3W or bme

To the thread starter I apologize again for having to type these opinions but in my experience they hold true.

Tillotson carbs don't tune any differently than Walbro carbs. The only real difference, from a user perspective, is the needles tend to be a little more sensative. Walbro carbs tend to be a little more idiot-proof because the adjustments are generally a little more coarse. In my experience, you can actually 'tune' a Tillotson, whereas a Walbro is more 'close enough..'.


Some of the ignorant 'opinions' 'round here are astounding.


Ford guy to Chevy guy: My car doesn't drive well when my tires are flat. Why is that?
Chevy guy to Ford guy: All Fords suck! Buy a Chevy!



That isn't helping anyone....

Thats why i almost never write it down in a thread cause people cant stand an accurate post on the reliability of some engines and people like you cry like little girls about ford v chevy you may continue wearing your blinders. I wont post another bit about it on this thread

LOL dont choke on my Diction, trying really hard not to offend but its not easy getting in any discussion about engines when every ones ignorant except the next guy who posts.

Honestly I'd just sell it. When you sell it tell them exactly what's wrong with it, give them a good deal, and let them fix it. 5 years is too long to suffer with an engine problem. You could have been having fun instead.

Send it back to your supplier........................for inspection.

I'm flying one and it is flawless, try rebuilding or even replacing the carb. Look at the reeds too.
I have a DA 150 that was troublesome, after exhausting all options I simply replaced the carb. It is now a monster!

Ok, here we go.....

I have never responded to these types of post either but I feel I must say something, there is not going to be an answer here that will fix your motor and there not be a right answer to posts like these....everyone will have their own personal oppinion based on their experience or their perceived experience. With that said:

Growing: I have been flying 3W since birth and I live right here in Tucson where DA lives.... I always get asked why I never switch to the 'other-side'... All's I can tell you is that both 3W and DA offer GREAT motors and I have always enjoyed my experience with 3W and their product. Your experience with your 3W is not the norm, obviously you have something wrong with the motor or ignition and you should have sent it in or at a minimum called a 3W representitive Cactus Aviation or Aircraft International long ago, I am sure they would have asked you to send it in to be looked at. For people to make statements that you need a 3W if you like tinkering with motors is just not fair to 3W. I have had issues with 3W engines myself, recently at the last Shootout but that doesnt mean they are bad motors, just that I had problems and I had them fixed, it was just unfortunate timming for me.

3W offers great motor choices and the motor you have has a good history without issues. Call Cactus or A.I. and get your motor fixed. To become a US distributor for 3W you must have a repair shop, this is what they do.

Good luck with your new motor, I have no experience with the DLE motor but I am sure it will run fine also.

Bill Hempel

Originally Posted by JoeAirPort

Honestly I'd just sell it. When you sell it tell them exactly what's wrong with it, give them a good deal, and let them fix it. 5 years is too long to suffer with an engine problem. You could have been having fun instead.

Good advice. I'd get rid of any product (DA, 3W, Ford, Chevy) that gave me that much trouble. Not saying everyone should but I've seen guys at my field have engine issues that last for years and cost them many planes.

Justin,
I agree with the earlier poster, this sounds like an ignition issue/hall sensor. Have you tried swapping them out?

You mentioned having the same issue on a 55cc, did you run the same ignition on both engines?
It has to be either ignition/hall sensor, batteries, switch, wiring short.

Chin up, I fought an engine issue for a long time as well, it's a good feeling when you get it fixed and you learn a lot (although mine didn't take me 5 freaking years!!!!).

Post back and let us know.

very well said billy. kinda what i was getting at but i am not as smooth on the sticks or with words as you, aj didn't teach me that snit