Novarossi REX R57HR-3DS With OS 70 CARB TUNING????????

[soggybongo]

Hi guys, after a little advice, i have a Novarossi REX R57HR-3DS with an os70 carb fitted to my trex 600, starts first time and idles perfect however at about 1/3 to 1/2 stick she splutters and bogs until i get above half stick then she is fine again.

Do i need to lean the mid needle along with the top? or something else.

I have checked all lines and put a new os8 plug in her but the simptoms are the same.

Oh and the engine is bearly warm on the back plate after hovering for 5 mins with tons of smoke.

never had a problem tuning nitro engines with 2 needles but the os70 carb has three.

all help greatly appreciated

[soggybongo]

forgot to mention that i have not done a full climb out yet as i want the bottom to mid range sorted out first.
current needle settings,
low set at factory default for os70 carb,
mid needle set at 1 turn out from closed,
high needle set at 1 1/2 turns out from closed

pitch set at -10 to +10 with zero pitch at mid stick

[soggybongo]

anyone got a clue???

[Paulo uk]

Lean the low needle. Because its the 70 carb you will end up with what would usually be way too lean on the needles. The carb supply's more fuel for the big block engine. Lean it one click at a time until it doesn't flood at centre stick.

P

[soggybongo]

just done a little reading on the os70 carb and it states in the manual set it so it idles nicely, mine does and i suppose it is a little leaner than the picture provided in the manual but i'll try leaning low needle a few small tweeks more tomorrow and post back - weather permitting.
Thanks Paul

[leckylee]

never heard of putting an os 70 carb on the rex i have both in the loft i think i'll do the same. any mods needed????

[Paulo uk]

Nope no mods. Helifreak has some threads about it...

[soggybongo]

i bought the engine from paulo uk, it also came with the standard 2needle carb, when i received the engine the os70 carb was already fitted. tried to remove the carb to give it a good clean but couldn't so it looks like it is a tight fit.

[leckylee]

well just got both out of the loft and hey they fit perfectly after removing the plastic sleeve. the os 70 was goosed anyway. this opens up a whole new opotunity. soggybongo dude i'll let you know how this goes this is going to be fun.

[soggybongo]

i'll be out tomorrow afternoon again if the wind keeps down so i should have some base settings for you.
as it stands this is my needle settings

low set at factory default for os70 carb, after looking at my os70 carb the low is about 1mm more leaned than the factory setting on this manual http://manuals.hobbico.com/osm/70sz-h-manual.pdf go to page 8
mid needle set at 1 turn out from closed,
high needle set at 1 1/2 turns out from closed

apart from a slight bog at 1/3 stick it runs sweet as a nut.

[leckylee]

just checked and the 91 carb fits aswell lol

What pipe are you runnig Paul

[Paulo uk]

Your mid or low speed as I called it in the pm is way high iirc when I ran it it was below 1 turn.

P

[Paulo uk]

I used to run a cy90

[soggybongo]

Your mid or low speed as I called it in the pm is way high iirc when I ran it it was below 1 turn.

P

get ya now i was just about to adjust the low needle (small screw) which is why i was confused as it idles fine.

[leckylee]

I used to run a cy90

the 90 pipe bolt holes are a bit to far apart fro the 50 size??