MVVS 6.5
 

A friend no longer in the hobby passed on a MVVS engine 6.5 Black head engine to me. It has a regular type muffler as well as a tuned silencer #3248n. Looking at the MVVS website it looks like a .40 size. What nitro setup should I use in it? Prop? Should I go with the tuned pipe? I'm looking to put it on a 40 size stick plane to use for sport flying. Thanks.

RE: MVVS 6.5
 

No nitro (if you must, 5% max), and 20% oil, preferrably half of it castor.
Props used depend on silencer and plane. The 3248 muffler, use with 9x6 to 10x6 props.

RE: MVVS 6.5
 

Thanks for the feedback. Will go with no nitro. I noticed the 2 needle valves. It is difficult engine to set up? Will probably run the 3248 muffler. Thanks very much.

RE: MVVS 6.5
 

Seatonflyer,


If it is the blackhead .40/6.5 GFS/R, the carburettor is by all chances one of the older styles.

It could either have the springy main needle, or a solid one.
The older carburettor had a simple air-horn and an idle-stop screw on top.

The low-speed needle is blunt ended and adjusting this engine for a perfect part throttle mixture may prove difficult.

The engine will load up somewhat, when run for more than a few seconds, at 1/4-1/2 throttle.


MVVS offers a partial solution, with a new tapered low-speed needle and nozzle set, but despite its higher cost, only upgrading to the new #3219 carburettor works well.

The new carburettor does not have an idle-stop screw (just a locator) and the air-horn is elaborately shaped, allowing better suction of fuel, even with a larger bore.

Here is a photo of the new .49/8.0 GFS/R with the new carburettor.

RE: MVVS 6.5
 

Dar,

The carb has the "springy" main adjust. I will contact MVVS Canada to see if I can get the newer carb to replace the old one on the engine.
Thanks,

Seatonflyer.

RE: MVVS 6.5
 

I have a few .40 MVVS Engines and used one this weekend on a WMA Raider Mk II. The header broke right at the exhaust flange. I have two other headers that are two-piece and was wondering where I can get the silicone o-rings to replace the (used) ones I have? Can't seem to find anything on the Morris website...