Test running

[WWhunter]

I have previously read where guys have run their Rotax 912's without a prop on. I'm just curious how many guys have done this and if it is acceptible.
I want to run up the engine on my KF and can do it with or with out the pro but am wondering if it would hurt anything to do a low speed test run without it.

[Av8r3400]

Yes, you can run a 912 without a prop without damaging anything. It is a little dangerous in that it can and will quickly rev up. Be very, very cautious.

Why are you wanting to do this? Running the engine without a load (prop) will not allow you to tune the carburetors or synchronize them. If your are running just to hear it run, I'd council patients.

[WWhunter]

Yes, pretty much just wanting to see if/how it runs. Mainly to settle my own curiosity, that it is a viable motor. I had a prospective buyer of the KF try and tell me that his Rotax 'expert' suggested the engine was basically junk and not worth anything. I know, buyers say all kinds of crap, but some of them get a little rediculous with trying to buy something for next to nothing. Its almost like they want you to pay THEM to take your garbage off your hands and are doing you a favor.

Plane has sat in the builders garage for many years. It was previously run to test the systems and I suppose it really wouldn't be a big deal to mount up the prop before starting.

The RANS S7 I bought a few years ago, sat for over 11 years in a quanset hut next to a lake. It ran fine other than a couple of issues that were electrical and carb related. When I replaced the cylinder/pistons with the Zipper kit, the inside of this engine looked like new! Even after all those years sitting next to water, although, it was frozen water in the winter. ;)

[mr bill]

I run my 912 big bore now and then with no prop, because I cant't wait. I make sure to limit rpm to less than 2500 and only run it for a minute or two. More than anything, it is a morale booster. Hope to fly this summer, before Oshkosh.

[kmach]

I personally would not run it without a prop.