I was wondering if it's safe to use afterrun oil in the YS motors. I've heard conflicting stories, with most people saying no because it will ruin some diaphram within the engine. I have a .63, and a .45 2 stroke. I'd like to make sure I'm taking good care of them, as they were both pricey motors. Also, I'm getting 14750 RPM with the .45 on a Macs tuned pipe with a 10x6 prop and 20/20. Is that the max RPM it will run?

I'd like to add to my interests to the original post.

What is the appropriate after-run care for a YS engine? I've just had my maiden flight of a YS-63 equipped Aresti. Everything went well, and I'm enjoying my first experience with a 4C engine -- loved the performance. I got the thing set up with a lot of help reading the posts on these forums but would like to be clear on keeping the engine healthy. The guy who got me started in RC has strongly emphasized the need to prevent corrosion especially in the bearings, making me live in fear of that insidious decay.

One suggestion that I gleaned from a post here is that you run the engine dry at the end of the day, but techniques like removing the fuel line to run it dry is complicated by the pressurized tank. Do you just empty or nearly empty the tank and run it dry or pinch the line to starve the engine dry. I'd appreciate a clear statement of the appropriate after-run care of my new (and future stable) of YS engines.

Rob Norman

I would guess that 90% of the users just run them dry and forget about it. Disconnecting the engine completely from the tank is done prior to running the engine dry. If you can't do this, at least pinch the lines off where they enter the engine, then run it dry and leave it pinched until it's time to go flying again.
The only after run oil commercially available for the YS which is fully compatible with the fuel system is "Ultra-Oil", available from Performance Specialties at 775-265-7523.
Since the YS engines run the fuel charge through the crankcase, they tend to have less corrosion problems than other brands of four stroke.
The biggest deal is getting the engine run completely dry when you are finished for the day. Do that and the battle is largely won.

Dave

Dave,

Thanks for the prompt reply.

I just did a test run on my engine and pinched the input fuel line to let the engine run dry. That was pretty straight forward -- I then disconnected the fuel line to keep it dry.

I'm still concerned with the possibility of bearing corrosion. I might be part of the 10% of users that will use after-run oil; on the other hand, if just running it dry is sufficient I like the easy way. Are the bearings sealed and therefore just not as vulnerable? If I did use after-run oil how would I apply it? Where and how much? Perhaps this would be done if there were longer layovers, say several months. Also, do you have a FAQ page somewhere that has this kind of information?

Thanks again for your support...

Rob

If you must use after run oil, it needs to go into the crankcase through the venturi. About a teaspoon full is about right. Be sure to remove the glow plug and run the engine with a starter for 10 or 15 seconds before fueling and running the engine again, otherwise it will be loaded up so bad starting will be a problem.

With YS engines, they must be completely dry before storage. Any fuel remaining in the regulator can cause problems. This is one of the reasons we recommend only synthetic oil fuels for them. Castor has a tendency to gum up the regulator during storage.

Good Flying,
Dave