I guess it depends what kind of noise, but I assume it sounds abnormal.
Correct me if I'm wrong, but I'm assuming it's rear disk-rotor induction. If so, does the rotor make a noise when you spin it on the backplate outside of the engine, and does it feel free to turn, without excessive side play ?
I assume you've checked the crank-pin is engaged in, and driving the slot in the rotor disk (please don't be insulted - I'm not sure how much experience you have). Otherwise, and again, assuming it's rear disk induction (I haven't seen a K&B 67 marine that wasn't, although I haven't seen many), perhaps the end of the crankpin is binding on the rotor disk as it turns, perhaps caused by inadequate clearance, perhaps missing backplate gasket ? continuing with this theme, does the noise improve if you loosen the backplate screws a little (maybe half a turn all round) - best to only turn it over by hand like this, but then the same would apply when the backplate is off the engine as well.
Food for thought:
Ian
Thanks for the help. Im not very experienced with nitro engines.... but i think i understand some of what you are talking about. The noise went away when i pulled the rear covor off (this has the wheel with an opening cut). It spins freely and doesnt make noises when off the motor, but then turning the flywheel by hand the sound is gone. I put the case back on (has an O-ring stopping it from bottoming out) and the sound went away. Not sure about the pin or anything else you mentioned cause i couldnt figure out how to get the flywheel off <_<
Sounds like you need some help putting the engine back together. The crank pin I'm talking about is the part which drives the disk on the backplate. When you look inside the engine, with the backplate off, the crankpin is pointing towards you. On the rotor disk (which spins on the backplate), there should be a groove on each side of the "window". The crankpin needs to engage with one of these grooves, when you put the engine back together. If you imagine the rotor disk positioned with the window at the top, the groove to the right of the window is the one you should use - if you intend to replace the backplate in the normal way (so that the carb is at the top of the backplate).
The hard part is engaging the crank pin with that groove. I normally try to do it with the piston at the very bottom of its travel, but no particular reason for this. At this point, the crank pin should be at the bottom and in the middle of the crankcase. I then set the rotor disk so that the appropriate groove is pointing straight downwards. Next, I offer the backplate into the engine, slowly and gently, then, when it's almost in, I rock the flywheel backwards and forwards a small amount, and try to feel and hear the crankpin "fall in" to the groove. If you get it right, when you look in through the opening in the carburettor, the rotor disk should move smoothly, as you move the flywheel in both directions. As you rock the flywheel backwards and forwards, you will probably hear a slight metallic click both ways, as the crankpin takes up the slack in the rotor slot. The window in the rotor disk should be open when the piston is at the top of its travel (about 2/3 of the area open), and hard shut with the piston at the bottom.
Hope this helps:
Ian
