Thread: Fuel Filter Service Bulletin

Hi All,

Here is the new fuel filter and fuel line Service Bulletin for most CT's except some of the newer ones. Please read this as it is very important and has some time lines.

Boy, am I glad we just had our annual and got this fix done! Otherwise, we'd be stuck on the 100LL diet until we got the filter changed....

Doug

my old filter was deformed

Hi Ed,

Many look like yours and many more are worse. It is because of the angle that filter is placed in by FD. When the filter is attached about 1.5" past the fuel shut off, it should either exit the firewall at that downward angle (straight in line with the nipples), it doesn't or should have a nice smooth sweep in the hose or have a piece of stainless tubing making the bend back upward. It doesn't have any of this. The angle is too sharp keeping constant pressure on the fuel filter nipples. It doesn't make any difference if the plane had 100LL or 91 with ethanol it still bends and crushes the plastic filter. When you get your firewall done or if you already have it done then at the next maint have the angle changed with a stainless steel sweep in the line. The angle is still too sharp even with the aluminum filter and kinks the line some as the fuel line leaves the filter. The plastic filters wouldn't have been deformed if they hadn't been put under a side load pressure.

I've burned maybe 5 gal of 100LL in the last 50 hours. I have tried to fly the plane every week, but have been using 5% ethanol gas for the last year, almost exclusively.

I guess I'll have to use 100LL to get to Oshkosh.

Hi Scott,

Wouldn't you have to run 100LL anyway since it would be hard to find 91 oct. If you have been using 91 oct. up to this point you can still use it. Read section 2.5 of the SB. It says it is "highly recommended" not "required". Different language all together. Depending on the fuel you use then there is a time line to get the work done. If you have been using only 100LL and switch to 91 oct. after the filter is done then you have to pull the filter and look inside after 25 hrs. If you have been using 91 oct. for a while then this 25 hr. inspection is not necessary. I have been using 91 oct since I received my plane 412 hrs ago without any issues. I used 91 oct. in my last Rotax 912, too (856 hrs).
I think I have only run 3 maybe 4 tanks of 100LL and that was because of cross countries.
Don't for get to take some Decalin for your 100LL.

I test the local Exxon 93 Octane and it is usually 5-6% Ethanol. Sometimes I mix it with ethanol-free 91 octane that I can get at a grass strip nearby. For local flights I bring a 5 gallon can, and end up burning it that day, keeping 8-10 gal in my tanks.

After talking with FD, it looks like the problem was ethanol-blended fuel sitting in tanks for months without being used. I could see where that would be a problem. If you're going to use mogas, you should fly often.