SERVICE BULLETIN #54
DATE: April 3rd. 2001 (Revised April 17th 2001)
SUBJECT: 912ULS and 912UL Engine Installations
APPLICABILITY: All Kitfox's using 912ULS and 912UL Engine Installation Kits shipped prior to May of 2001
COMPLIANCE: Mandatory, before next flight
FROM: SkyStar Aircraft Product Development
As SkyStar and Kitfox™ owners gain field experience using the Rotax 912ULS engine, some issues are showing up. While the Rotax 912UL engine has proven to be a trouble free installation in Kitfox™ Aircraft, the introduction of the Rotax 912ULS, with its increased horsepower and higher compression ratio, requires some special considerations.
During initial start and during shutdown the 912ULS creates a good kick, substantially more than the 912UL. This kick has created carburetor venting problems, dislodging of carburetors, ignition module isolator breakage, and exhaust system cracking. During flight operations the engine installation has been performing well. The Kitfox™ engine mount uses a Dynafocal Rubber Isolator mounting system approach (except for Series 5 and Series 6 round cowl installations) commonly used in the aircraft industry to promote smooth operation. In order to reduce the effects of the initial kick at engine start, the engine mount isolators need to be stiffer.
MANDATORY FOR ALL 912S INSTALLATIONS, EXCEPT FOR SERIES 5 AND SERIES 6 ROUND COWL INSTALLATIONS
FIGURE 1
MANDATORY FOR ALL 912S INSTALLATIONS
3. Inspect your exhaust system for cracks. Check all welds, header tube junctions, and stinger for cracks. If your Muffler does not have the gusset as shown in figure 2 then the muffler will need to be sent to SkyStar for the gusset installation. Any cracks found need to be repaired or replaced before next flight. See return policy at the end of this bulletin. Check the stinger outlet hole clearance in the cowling. You should have a minimum of 1/2” clearance between the cowling and the stinger to prevent failure of the stinger.
4. Inspect engine mount. Check the engine mount for cracks. Report any cracks found to SkyStar Technical Support. For Kitfox™ Model 1 through 4 owners that have upgraded from a 912UL to a 912ULS check your engine mount for the gusset shown in figure 3. If the gusset is not present then you will need to purchase an updated engine mount or have your engine mount updated by SkyStar.
5 Inspect the ignition module mounting on the engine for cracked mounting hardware, cracked isolator mounts, broken wires. Repair or replace as necessary.
6. Make the appropriate entries in your logbook.
While this bulletin is intended for the Rotax 912S engine installations. It is recommended that 912 installations also follow items 1 through 6.
During preflight be sure to check your engine installation over. In-particular the engine mount, exhaust system, and ignition modules.
SkyStar has put together a kit for Kitfox™ owners that are due for annual isolator replacement.
P/N: 64804.000, 912 & 912S engine isolator kit. This kit includes all rubber isolators, the .93” spacers, cotterpins and extra washers. Price $75.00
Contact Customer Service at 208-454-1443 for any parts or repairs
Contact Technical Support at 208-454-1665 if you have any questions regarding this bulletin.
RETURN POLICY
Parts in need of repair or upgrade that were supplied in 912S engine component kits through SkyStar Aircraft Corp. to the original purchaser of the engine component kit are covered for repair or replacement. Owners of 912 engine component kits that upgraded to 912S engines are not covered under this policy.
All effected parts must be returned with-in 90 days of this bulletin (by July 3rd of 2001) to be covered.
When shipping parts, contact customer service for an RMA# prior to shipment.
Write the RMA# on the box.
Send a short note with your name, return shipping address, and the reason for the return.
Ship to address:
SkyStar Aircraft Corp.
Attn: Product Development
3901 Aviation Way
Caldwell, Idaho 83605