First you must register with eBay, if you haven't already done so. It is nearly essential to include photos of the item. This is especially true if you are completely new to eBay, with no feedback.
You will need a scale to weigh packages, since this (together with package size) determines the shipping cost. Most modelers have some kind of scale in their shop. In my experience, the postal service is the best way to ship.
Attaching photos is far easier now, compared to 10 years ago when I started. The old cliche "A picture is worth a 1,000 words" certainly applies to on-line auctions. So you need a digital camera to upload photos onto your computer (or borrow one, if you only plan to sell a few items). I'm still using my 10 year old Sony FD Mavica with a 3.5 inch floppy disk drive. It works for me!
If these engines are non-throttle (i.e., C/L & F/F), then its only necessary to list in the control line & free flight category. If they are radio engines with throttles that are convertible to C/L you may also want to list in the R/C Engines category, but it's not necessary.
Use a descriptive title with the right abbreviations so your engine turns up when someone searches for a closely related item. An example: OS FP .10 C/L and F/F Engine for Junior Ringmaster Kit (copy item No. 300464773389 in the search field). Another example is GMA-Jett .50 Control Line Stunt Engine + Tube Muffler (copy item No. 290499089766 in the search field).
Describe the item thoroughly and honestly. Cover all bases like packaging fees (if any), postage, whether you will ship to other countries, any discounts and combined shipping for multiple items, your return policy, etc. A descriptive and comprehensive item page often results in more bids and fewer questions to answer.
Finally, decide the minimum price you will accept for the item. This is important when you have to enter an opening bid price and an optional reserve and/or buy-it-now price.
Remember that the value of anything is determined by the market, at the time its offered for sale. Like houses, gold bars and stocks, the winning bid may be less than what you paid. On the other hand it could be a lot more if your item has collector value, or is just popular and in limited supply.
Check out this current auction: NIB Vintage Rare Aero .35 C/L Model Airplane Engine (copy item number 160515774540 in the search field). These are unique and very rare engines, but I don't think they sold for more than $50 when produced back in the 1960s, probably less. Yet this one is currently bid up to $910.
After launching your auctions, check on them once a day to see how the bidding is going and answer any questions. If you did a good job describing the item(s) with photos and text, most questions will be about foreign shipping costs (if you choose to do foreign shipping). Hope this helps! Good luck and Season's Greetings! EWP
Topic: Listing engines on Ebay (Read 1723 times)