Air Hobbies Twin Cylinder
 

Hi,

I picked up this engine and I'm trying to determine what size it is, maybe someone out here can help. It is an Air Hobbies engine, with a unique muffler system. I'm attaching some pics.

These things any good?

Thanks!

Pic 2
 

Another pic

Last Pic
 

Last one

Air Hobbies Twin Cylinder
 

Looks likw 4.2 twin, the cylinders and pistons are 2.4 Sachs, the carbs are Walbro.. If you have the "timing stick" ignition it sometimes works....I have worked on three Air Hobbies engines..Two were 4.2s..One was so tight it would not run, one was machined with the front bearing bore .015 higher in the case than the rear, then the rear crank extension was hand ground smaller (it no longer fits the bearing) so the crank would turn after the case was bolted together...The twin was a 6.4..It ran after I put my ignition on it and did some other things to it, forgot exactly what....I called about the 4.2, Charlie said it could not happen. I was a machinist for 30 years, dont think my surface plate and indicator are .015 off...He said he would fix it. I still have it in the shop..I could probably bore out the case and sleeve it, then bore it in line with the other half. That still leaves the crank with the rear shaft out of round and undersize..I will use the cylinder, piston, and carb for something else....After I sand blast the red paint off.... :D

Math
 

Lets see 2x2.4=4.2????? Maybe a 4.8??? :D
Anyway not not one of the better engines out there. That neat muffler really heats up the crankcase

Air Hobbies Twin Cylinder
 

OOPS....I guess Alzheimers is not that far away :D

Air Hobbies Twin Cylinder
 

Thanks for the info guys, I appreciate it! It was given to me, so I guess I got it for what it's worth!

Air Hobbies Twin Cylinder
 

Spend a few bucks on shipping and send it to Ralph at rcignitions.com and let him look it over for you. It will be better than losing a plane it you put in the air and have problems with it.
Milton

Air Hobbies Twin Cylinder
 

If you have a buyer for it sell it or else like the previous post said send it to Ralph at rc ignitions. There ignition system sometimes works but usually quits deadstick once in the air very undependable motor. Lots of bearing problems and ect as dedscibed above posts