I am working on my first conversion Weedeater 25cc into a Sig Kadet senior. What do I have to do
to get this thing ready? The engine is torn down and I am ordering the kit from Wacker engines.
I was planning on modifying the stock exhaust with a single large bore stack running out the bottom.
any help would be appreciated. Also can I cut the flywheel or do you reccomend sending it out?

Just make sure you keep your radio eqiupment at least 9" from the motor if you are going to be using the stock ignition. Do not use metal clevises to link the throttle servo to the throttle. The muffler you plan on modifying is fine. I don't have that engine but I believe mounting that engine isn't that hard. Good luck![8D]

As for cutting the flywheel fins - unless you have machine shop experience and access to a metal lathe, send it out. The flywheel needs to stay balanced. You can't simply grind or cut off the fins.

Dr.1

Yes you can

I own lathes and mills (check the sig) And the flywheels on some of these little engines aren't even drill on center. If you are careful, you can cut the fins off with side cutters, and file them smooth. Just don't cut into the main body of the flywheel. If you have a prop balancer, you can re check it… otherwise, you should be fine. Remember… you will be spinning this engine slower than it would have in the weedeater. And, the engine isn’t balanced internally perfectly anyway.

I’m sure I’ll start a fight over what I just said… but you will be fine for a low output engine. If you were looking to spin it 10K rpm’s or higher… I would tell you a different story.

Good luck

In my experience, it makes a very noticeable difference if you balance the flywheel. We turn these engines anywhere from a low of 6500 to a high of around 9500 rpms. Balancing props and flywheels make the engine smoother and will make the airplane and its equipment last longer.

AV8TOR

No fight here, Dr Honda, but you do what you want with your engines and I'll do what I want with mine. Side cutters and files? Where does the sledge hammer come in?

My advice remains: To be on the safe side, people, send it out to be machined.

Dr.1

See… told you

Without a doubt… the engine will run better if balanced. But, the fan blades cause allot of drag, and the performance benefit of removing them by a non machinist type of person, and having it a little out of balance, out weighs leaving them on. Especially on the Featherlite Weedy engines. (typically low output) The build quality on them isn’t what I would call good. Don’t get me wrong. They make a fine, very light conversion… It’s just that I have smaller Echo (Kioritz/Zenoah Japan) engines making more power.

The original question was if they could remove the fins at home. And my answer is still yes. IF… the builder is confident in his/her abilities to modify a mechanical part.

The comment about the side cutters, and a file was made because the cast alloy that these flywheels are made of is soft, and be cut with the most simple cutting tools, and was not meant as a joke. The last engine I did had it’s fins cut off with a set of pliers. Yup… I just twisted them off. Of course, it went into my mill after to get a cleaner trim, and a resurface so I could bolt on a prop adaptor… but that’s just me.

Just as an FYI… have you checked the balance of a stock flywheel? Most of them are counter balanced for the crank, and aren’t “in balance” if checked on a prop balancer. Also, the attractive force between the magnets and the magneto will change it’s dynamic balance while it’s running.

Anyway… it’s your engine… do what you want. If you don’t cut into the main body, it will be SAFE.