You have to realize it was a while back. I know I used the same fuel-oil mix as my 3-w. 50 to 1. Prop was a 32x10. Can't remember if I used a 4.8 or 6v battery. the mufflers were the ones that cam with the engine.
I had a very hard time starting it. I had to use a electric starter on it. One day after fighting it all day I finally got it to start in the dark and found of the heads was warped. It glowed in the dark. I waited for three months for a replacement part. They told me they had never seen that. LOL but i would get a new and improved head. Still had trouble keeping it running.
just the fact that they didn't want anybody here to work on them would be enough to keep sales down. by a high price for engine and have to send it to Spain would make selling them almost impossible.
hope I helped. Dennis