A Couple Of Cox Starting And Polishing Questions

NEW222 Mon Aug 10, 2015 8:36 pm

Hi there. I have a couple of questions that are boggling my mind. First will be the obvious, but not to me. When starting a Cox engine, it is said to drip a drop of fuel into the exhaust port. I have always rotated the prop so the piston is at its lowest and give it a little squirt on top of the piston using a 2cc syringe. I have just been reading things and now believe that I am not doing it right. My feeling now is that I should have the piston at the top and not putting fuel on top of the piston. Could someone please tell me which way is correct.
Now for question number two. Polishing a Cox engine crankshaft. How exactly is this done? I tried searching and the article I found was not too clear. Thank you.

**RknRusty** Mon Aug 10, 2015 9:27 pm

I think it's better to rotate the prop so the exhaust port is closed and drop some fuel on the side of the piston, then flip it a couple of times. Light and crank. That's what all the Cox instructions say too.

For polishing a crankshaft, I cover the splined nose with tape and chuck it in the drill press. Then start with a strip of 800 grit sandpaper and light oil, and finish with 1000 grit to get a mirror polish.
Rusty

NEW222 Mon Aug 10, 2015 9:28 pm

Sorry to add another question. I am reading and seeing mention of a crankshaft bushing. As I do not see a bushing, is this the very front of the crankcase in which the prop driver is against? I now figure it's about time that I start to learn a bit more about my addiction.

**RknRusty** Mon Aug 10, 2015 9:36 pm

People have bushed them, but it's not a commonly done mod. There are threads around here somewhere that discuss it. You could possibly save a shot crankcase if you bored the nose bearing out and insert a bronze bushing that fits the crankshaft. Better be able to bore perfectly straight though. I would never bother to try it.
Rusty

NEW222 Mon Aug 10, 2015 10:38 pm

Thank you for your help. Your answers have made the mud more clear now. Very Happy

getback Tue Aug 11, 2015 6:29 am

Just to add if you have the crank shaft out use a Q-tip with denatured alcohol on it or fuel will work and swab inside the bushing / crank geranial to clean any residue out for your new fit , and bee sure to clean the crank good before installing to remove grit . Eric Very Happy

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A Couple Of Cox Starting And Polishing Questions

A Couple Of Cox Starting And Polishing Questions

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Re: A Couple Of Cox Starting And Polishing Questions

Re: A Couple Of Cox Starting And Polishing Questions

Re: A Couple Of Cox Starting And Polishing Questions

Re: A Couple Of Cox Starting And Polishing Questions

Re: A Couple Of Cox Starting And Polishing Questions