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View Full Version : Series 5 Manifold & Carb Location, need advice



SWeidemann
03-07-2015, 12:51 PM
I will be installing a new 912ULS and am looking for information about manifold & carburetor swapping (from side to side). The (runout) engine I removed had manifolds & carbs swapped as a unit (with carb actuation & fuel inlet on the inside) and ignition coils re-located. My main question is; may I leave the carbs on the existing sides and swap manifolds only, or will I run into a cowl clearance issue? It seams it would be easier to synchronize carbs if they were positioned that way. ( The Kitfox instructions say to swap the carb & manifold as a unit.)

Any & all facts or opinions will be entertained.

Thanks much

Skot

kmach
03-07-2015, 09:07 PM
I think you should be fine if you switch the carbs with the control arms to the outside. The controls on the carb are out ~ 1 1/8 " more from the center than the the "smooth side".
Unless something is allot different under your cowl, I think you will have room. Not too big of a deal , have a look from the front cowl openings, on my 5 there is quite a bit of space from the side of the carbs to the cowl.

I am going to switch my carbs so the linkage and fuel hook up are on the outside , at carb rebuild time. waiting for the weather to warm up, will need to do a carb sync after the switch and it is no fun doing it when it is below freezing with the big fan going.

Av8r3400
03-07-2015, 10:20 PM
This last summer I reworked my Yellow IV to swap the carbs so that the throttles were on the outside as Rotax intended. Other than rerouting where the cables pass through the firewall and needing a new, longer enrichener cable set it was a breeze. As you said, syncing is now much easier.

SWeidemann
06-26-2015, 05:13 AM
As a field experience follow up, I now am back to the configuration of manifolds "out" on each side and carbs with arms on the inside again.

After trying "carb arms out" (which did fit fine and I thought it was a great configuration), I found my throttle cable & enrichment cable on one side were now too short to reach. So...the config is back to the way it was when I bought it only with a new engine.

In a phone call to Brett at LEAF, he pointed out he has observed more issues with carbs mounted further out from the centerline than those mounted closer to the engine center (as the 912 is configured when shipped). Trouble with my Model 5 is that there is nil clearance between the carb flange and the top engine mount with the manifolds as shipped from Rotax. I believe the later Model 7 series has a "low interference" engine mount.

The project continues.

Skot