Hy to evrybody in the forum. I bought a used aeromarine cat with a quickdraw engine. It has not been run in four or five years. piston ring was pressed and rusted in the grove. Cylinder looks OK and everithing else too, it was well lubricated on the inside. Somewhere i read about using the ZENOA piston. Is that true? where can i get some information about it. Also I am not Sure if the engine is a 25 or 35. Are there any schematics of this engines. I will apreciate all the help or information.

This might not be the answer you are looking for, but I would strongly suggest sending that engine to Mitch at Quickdraw and have them refresh it. I am no expert on QDs but I think using the Zenoah piston is only applicable with some of the more recent year QDs. One way to know if you have a 25 or 35 is the size of the piston...25cc = approx 34mm dia piston. Also the 35s don't have a key to hold the flywheel on the crank. I beleive the carbs are different also, but hopefully someone here with more experience with these motors will chime in.

Yes, I would atleast call quickdraw. There should be some #s on your motor that they can use to Identify it. If it is older like you said it is probably not a 25ht or HighTorque motor. And is most likely a 25hr or HighRev. Or it's a 35cc. The only motor that uses a zenoah piston is the HT. But what ever motor you have is a score in my eyes. Go to quickdraws website there is a lot of info on there aswell as the big differences in the 25cc motors.

The older 26cc Quickdraws had soft steel liners that wore quickly. A new liner would really improve the engine. Quickdraw can provide all the upgrades. The new 35cc engine has a steel rod as well.

Lohring Miller

Thanks for your help. Yea I think Its best to call quicdrawn and ask them, most probably I will be sending it to them.


Great forums.

The older 25! is a 70+mph motor! :o

Hy to everybody on the forums:

The engine is a QD-35. I got in touch with TODD in QUICKDRAW and the head assembly was sent to them for replacement of cilinder and a new piston. By the way them guys at QUICKDRAW have a great service. And I want to thanks all of you guys for your help. Keep up thew good work, and MERRY CHRISTMAS to every body.