messy Stratus

[Rada70]

My heli gets drenched (engine area) with fuel every flight. I tried to trace the problem with no success. I checked the head screws the bottom plate, and changed all the tubing. what do you guys think? I'm running OS cspec91 with BB carb, a Viper head, and hatori muffler. thanks

[Alfred]

Are you running it that rich that the fuel is spitting out the carby?

[DavidH]

Check where the muffler is mounted to the engine. You will probably need to use some RTV or epoxy to seal the flange. Also you can smooth out the header surface by wet sanding it with some 600 grit sandpaper on a piece of glass.

David

[Rada70]

The muffler is not leaking, but I changed the o-rings just to be sure. I am going also to check the muffler mount Dave. The needles settings are (Main @1.5 turn low @1.5 and mixture open all the way). I was told that is the right way to do it, isn't it? Thanks

[DavidH]

My needle settings on the CSpec with OMI BB carb and Cline are
1 1/4 on the main. The midrange needle is 1 turn. The low end adjustment is centered.
That is 30% Cool Power, SB 16 muffler, 7.91 gear ratio. I was flying it Friday and Saturday in 90 deg temps and about 60% humidity.

(Main @1.5 turn low @1.5 and mixture open all the way

Main needle is the long needle that is towards the bottom. That adjustment is close, may be a little to the rich side.

Low adjustment is the cam adjustment with the brass plate. That should be centered.

Mid range is the top needle that is short. I have that one about 1 turn open.

I have no idea what mixture open all the way means.

I was not referring to the Orings leaking on the muffler. I was talking about it actually leaking between the header and the exhaust flange on the engine.

David

[Dr.Ben]

If the muffler ends up not being the cause, then you, sadly, have to check and see if fuel is leaking past the front seal area of the engine's crankcase.

Ben Minor

[Rada70]

Hi Dave, The mixture I meant was the low adj'. I have it fully open. I checked the muffler header, and it's not leaking :( . I guess it has to be the front seal as Ben suggested, but how do you make sure? thanks.

[DavidH]

The mixture I meant was the low adj'. I have it fully open.

If your running the low end with it set all the way to the rich side. I would think you have something in the needle openings. The SZ carbs I have seen the low end was in the center position on most of them. And the ones that were not were just slightly to the rich or lean side. That difference could be in the fuel being used.

Counter clockwise on the low end mixture screw richens the low end mixture. Clockwise will lean the mixture. The cam can only be turned about 60 degs from center.

David

[I3DM]

One of my stratuses used to be full with oil in the engine area (even when i sealed the muffler flange with RTV). it turned out the motor's backplae seal was slightly ripped, changed it and its been clean as a whistle ever since.

[EricLarson]

Almost 100% it is leaking at the flange of the header and the engine. You need KSJ PN600 OS91 muffler gaskets from ron lund at www.ricks.com.

It may not look like it but it probably is. If you are using no gasket or the aluminum one it is leaking for sure.

The KSJ gaskets are the only think I have found that work 100% and are simple. Use HIGH TEMP loctite on the muffler bolts and you will have no issues with loosening or blowing out the gaskets. They last quite a long time also.

[angelob]

I have a Hatori 998 on my OS 91. What I noticed is that since the flange is drilled for both OS and YS engines, the YS holes are extremely close to the port opening. I filled these holes with JB weld and it cut down the mess dramatically.

Angelo

[I3DM]

Eric, just a small correction - the URL is www.ronlund.com and not www.ricks.com :mrgreen:

[Dr.Ben]

As noted, confirm the muffler seal first.

If the front seal is leaking, you'll be spraying largely unburned fuel.

In the past, I've stuck a small piece of cardstock up under the shroud near the front bearing. Hover for a few minutes. If the front seal is leaking, you'll see a tell tale spray pattern on the card. Fortunately, after a run in the early nineties of OS SFN 61's that were infamous for leaking fuel due to QC issues, I've not heard much about it from that particular mfg.

Ben Minor

[EricLarson]

:) OOPS thanks :mrgreen:

[Rada70]

OK guys here is what I found. The leak is comming out between the white plastic elbow that comes out of the regulator and the segulatoritself. Should I clean it and glue it back to the regulator, or what do you think? thanks

[EricLarson]

clean good and goop works pretty well.

[DavidH]

The leak is comming out between the white plastic elbow that comes out of the regulator and the segulatoritself.

Why do you need the elbow? I connect the fuel tubing directly to the nipple on the regulator. I cut a piece of fuel tubing about 1/4 inch long and slip over the fuel tubing. I then push the 1/4 inch piece down over the nipple. Been using the fuel tubing directly to the regulator nipple for two years. It has not came off except when I pulled it off.

David

[Rada70]

OK, thanks guys