Im setting up my first YS 91FZ and want to know how to set it up for refueling. The fuel diagram in the instructions does not include how it is to be refueled. I would prefer to use a fuel dot system for refueling if this is possible. Also, should I use some kind of sealant/gasket on the threads of the exhaust tube to keep it from leaking oil through the threads and leaving burn marks on my muffler?

Thanks, Bozwth

By theory, you should be able to install two tees and use fuel dots for fueling and venting. That is if you vent between the checkvalve and the tank and that your regulator is working properly on the fill side.

A friend uses the Dubro fillers with a dummy line in one of them to as a vent. I unplug the fuel lines because mine is in the open.

Use some teflon tape or high temp silicone on the muffler threads.

Enjoy,

Jim

Agree, I have my 91fz set up this way and it works fine.

When you say "your regulator is working properly on the fill side." Is that what is supposed to keep the engine from flooding when I fill the tank? Today someone told me that I would have to clamp the fuel line with a pair of hemostats while I refueled so that It wouldn't flood the engine. Is this not necessary if the regulator is working properly?

Bozwth

Mskyhawk,

Are you saying that you use the two fuel dots and two tee's method and It works just fine or are you saying that you use the Dubro fueler or disconnect method. Do you have to use hemostats to keep it from flooding the engine?

Bozwth

The only time I have problems with flooding on my YS is if I don't relief tank pressure after a flight and let it set. Then it is a little hard to start. Fueling I have no problems unless I forget to remove my vent fuel dot, in which I have.

Yes, two dots, and no hemos unless I forget to open the vent.
Then I get a little flooding.

The system w8ye described works well.

Back again, The dubro re-fueler works for a little while then it will leak and with ys engines, a fuel pressure leak is bad. Lost a plane because a screw together fuel filter came loose. lost pressure, sucked air and died on takeoff about head high. Which leads me to another topic. Be darn sure your fuel filters are tight if they are the screw together type! It was a learning experience!

I've heard that about the Dubro fillers, thats why I am going with the fuel dots.

Are fuel filters that critical with this engine? With other engines I've had better luck without fuel filters. The seem to restrict the flow just enough to cause problems. Is is a different story with the pressurized system? And if I must use them what brand do you recommend?

Bozwth

It is a different story but to be honest with you, I took mine out but I double filter my fuel before it goes into the tank in the plane.
Critical with this engine?....yes, you don't want anything getting in the regulator or the check valve or you will have problems.
I have a filter in my fuel can plus another in the fill line from my electric fill pump.
I use the Hayes fuel filter " screw together" but not in the plane.

The Dubro fillers have some problems. One, dirt gets on the end of the male piece easily and transfers into the female piece which jams the plunger "in" which restricts flow and lets air in or out of the system. The second thing, that some people swear by, is that the O-ring will sometimes swell which causes the same problem as above.

Many that have had trouble with the Dubro fillers continue to use them but they keep and eye on the plunger. If it doesn't return all the way, they set there and pick at it until it does.

Due to the design of the Y-S regulator and the existance of the check valve, theoretically, you can just use the two tees and the two fuel dots. But don't press your luck by not opening the vent.

Jim

Just a little tid-bit... When fueling for the second (third forth etc) flight, make sure you open the VENT first before the feed! These engines produce a considerable amount of pressure, and if you don't releive it by opening the vent first, you'll be squirting fuel all over the place! (The voice of experience talking here LOL)