airega1

My Feedback: (204)

Today I started for the first time my 6.4 Brison, I expected a more solid running engine. I ran it with no cowl, Lawn boy at 40-1, fresh 87 octane gas. My final results were, 6260 RPM's with a Mejlik 26x12. I didn't stay at top end for more than 10-15 seconds at a time. The engine ran rough at top end even after many needle settings. My questions are, is the Brison recommended Mejlik 26x12 too much prop? does it need a lot more break in time? Brison recommended the carbon 26x12 prop and stated to try to reach 6540 RPM's. The engine ran pretty cool throughout all the run time. It just did not smooth out at top end. It was not running rough to where you would expect a plug to be out any info would be appreciated.

Big_Bird

My Feedback: (1)

I have one on my Lanier 300S and really like how it runs. They do need a bit of break in time but that is mainly for the rings to seat. It should run relatively smooth from the beginning. A lot of the smoothness has to do with what it's mounted on. I assume that you balanced your prop. Both cylinders are firing or you wouldn't be getting the rpm that you are seeing. I run an RCS 26 x 10 laminated prop and get between 6200 and 6300 rpm.

You may be expecting a big twin to be glassy smooth and this just isn't the case. Even though the system is balanced mechanically, you still have the firing pulse to contend with each revolution. What is your engine mounted on and what is your expectation of smooth?

Ken

BAS

My Feedback: (28)

Reference your Brison make sure plugs are gapped correctily around 21 or 22 thousands and make sure your plugs dont have any cracks in the porcelian . Also i think the 26/12 prop is to heavy to start with also like the previous post what are you mounting it too I had mine mounted to a 300 lb work bench. ??