Needle WAY open on OS91SZ Dual Viperhead + OMI BB Carb. :-?

[Knud Pedersen DENMARK]

Hi
I have an OS91SZ Dual Viperhead (enya 3+5), OMI BB carb, Hatori 939, wildcat 30% LV.
I have just convertet my chopper from a Fury extreme to a Stratus.

I have trouble with my engine getting lean.
After flying the back plate is VERY hot.
It does also loss power in Tictac.
When doing BIG BIG flips, the engine crakle when the heli is vertical (lean)
Idle ¼ to the rich side
Medium 3/4 open
High speed 1 ¼ open.


Today I did richen it up a lot…
Ending up with these needle settings:
Idle ½ to the rich side
Medium 1 ¼ open
High speed 2 ¼ open.
I also remove the filter between tank and carb…..

Know it does not getting hot, is pulls okay, it just go a tiny bit rich when hovering in idleup (15500 rpm)

Anybody know why I have to open the needle that much?
The plate under the engine is full of full (taht it was also back when it was an fury) – could the kline have a leak????

[Laurens]

There might be a leak at any place. Check everything.

[Roxxter55]

Hi Knud

I have the same SZ with the OMI Cline mod

I dont think there is a problem with your Cline reg, but mabye a leek in the system, tjek the tank pressure after 2-3 min flights, and stop the engine, it must be like a balloon, let it stay for a 10 min time to see if the pressure i dropping

The normal sign of this problem could also be a sloop in the bearing

Have tried the same problem, with my SX 91 with Cline, then I check the back bearing, and yes it needed to be replaced (not total out of use)
After the replace I went back to the normal settings again

By the way - the OMI Carb mod is the best I ever have tried, so fare It runs like a dream, after some start problems :D


Br

Carstensen

[Kinger]

You could have a crack on your cline. Check around the nipple where it attaches to the high end needle assembly. Mine developed a hairline crack right at the base which allowed air to come in and throw off the mixture.

[Knud Pedersen DENMARK]

Hi Kinger

Did you glued the "crak" on did you replaced the Cline?

ChopperKnud

[Kinger]

I tried to JB Weld the crack, but no luck. Ended up having to use a new Cline.

[Knud Pedersen DENMARK]

HI

It does look like there is comming fuel out of the backside on the Cline....
Would it be stuoid to tey and open it, by removing the four screws?

PS: There is plenty of pressure in the tank, after more 1/2 hour, it does the pressure sounds the same way as removing the fuelline right after a flight...

ChopperKnud