I have a new super tiger .61 ABC and when I was trying to break it in I noticed it made a bad sound when flipping the prop and it was hard to get it past top dead center,when it hits TDC it makes a squeeking noise,I know it has to due with the piston and sleeve.I did get the engine to run and got about two tanks through it but when it cools down it get's tight again.This is my first super tiger will it get better the more I run it?

Thanks

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Normal and there would be something wrong with your engine if it did not do this when new and don,t be flipping it through by hand dry.

Just the sign of a good tight ABC engine. It'll get much smoother with age as the parts set in. You'll probably find it starts easier once its hot from a run and the parts have expanded a bit.

The 61 is a solid performer. I think it is the best overall of the three common St models (45, 61, 90), all of which seem to share the same carb. The carb appears to have been designed for this motor, which makes it easier to tune than the other two models. I'm not looking at their site right now, but as I recall they actually make two motors of this displacement, right? One is a ringed motor, which is what I have. Clearances for the ringed motors are set looser than the unringed versions, because the ring is not a total circle but has an end gap. This allows the ring to expand as it heats to create the final tight seal. Versions without the ring are set tighter and actually loosen with heat to create the final dimension maintained during running. Break-in of my 90 has been fussy, but I suspect that has more to do with the compromised carb situation than the ring, as my 61 is also a ringed motor.

This engine has a tapered sleeve. The top of the sleeve is a tighter fit on the piston than the bottom. The correct running clearance is realised at operating temperature. This engine should NOT be turned over cold when new. For the first few runs carefully heat the head with a blow torch or heat gun until the engine turns over freely. Then start it. Use a smaller than usual prop that will allow the engine to reach it's operating temperature and RPM but with a slightly rich (NOT SLOBBERING) needle setting. Run it for two or three runs with say an 8-10 oz tank, then it will be ready for use.

Ed S

Thanks,this is the first engine I had that it was that tight.My OS. engines were never like that,just thought I would ask to see if it was normal.