990 needles settings

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
D

deephis46

Well-Known Member
Messages
46
This day I tried a 990 carb, but I only got 5 seconds fired on elevation. I have tried in my house and it's fired just fine with stock needle settings out from the packaging. Does it need to adjust the needle again?

Tyo
 
deephis46 said:
This day I tried a 990 carb, but I only got 5 seconds fired on elevation. I have tried in my house and it's fired just fine with stock needle settings out from the packaging. Does it need to adjust the needle again?

Tyo
Click to expand...

GENERALLY the default setting for ALL Walbro (-type as well) carbs is 1 1/4 LOW, 1 3/8 HIGH.
To determine this, simply perform as per nitro carbs - screw in GENTLY, don't force it, until it stops, then UNSCREW (CCW) to the stated values.

Stock engines tend to need LESS fuel, so these settings may be rich.
Similarly an altitude effect may require a leaner setting, if I read your message correctly, but only consider SMALL changes, perhaps 1/32 at a go.

There are plenty of tuning videos, and threads.
There's a nice SIMPLE tuning video set-up by Trip, which should be easy to find.
All engines and carbs are very slightly different, so they will vary.

As with 1:1, let a brand new engine run slightly rich for a couple of tanks before tuning - leaning and optimising - and considering full throttle.

Al.
 
atom3624 said:
GENERALLY the default setting for ALL Walbro (-type as well) carbs is 1 1/4 LOW, 1 3/8 HIGH.
To determine this, simply perform as per nitro carbs - screw in GENTLY, don't force it, until it stops, then UNSCREW (CCW) to the stated values.

Stock engines tend to need LESS fuel, so these settings may be rich.
Similarly an altitude effect may require a leaner setting, if I read your message correctly, but only consider SMALL changes, perhaps 1/32 at a go.

There are plenty of tuning videos, and threads.
There's a nice SIMPLE tuning video set-up by Trip, which should be easy to find.
All engines and carbs are very slightly different, so they will vary.

As with 1:1, let a brand new engine run slightly rich for a couple of tanks before tuning - leaning and optimising - and considering full throttle.

Al.
Click to expand...
Yes, you are correct, I'm on altitude. But my engine is stock KM one the only upgrade I have made, Dom V2 silenced and this 990 carb. Oh, and the exhaust got 'shoot' (I don't know what it's called, backfired maybe)
So I turn 1/32 at a go?
 
There have been several threads in the last 2 months on engine tuning and carb settings.
One of them has a link to the old video from Trip.

This will help you a lot.
Before this, just take a look at the Engines section and follow that - it's as good as it gets, basically.

Have fun.
YES, don't be afraid to change the settings, but only turn by small amounts. 1/16 is probably too much unless it's obviously 'chugging'.

I would suggest once you think you've set it, you switch off, then 'count in' to see just what setting you arrived at and how far away it is from the 'stock settings'.

Al.
 
How many on here run the 990s? I was thinking of this for a upgrade. I have the V2 30.5cc. Has a nasty low end bog that i hear in all the KM 30.5cc vids on youtube. I have maybe half tank ran through mine so far. No matter what i do i cannot tune it out. So i know its a carb issue. I have read alot of great things about the 990s so far. I was just about to start a thread when i searched and found this thread... :cool:
 
I haven't tried it yet, but just picked up a 990 for my 30.5 KM from gizmomotors.com it's only $33! Cant hurt!
 
my g290 came with a 990 and i'll never go to another carb. even with no choke it only takes 2-3 pulls and fires up right away. i find it alittle more touchy when tuning but much better then any carb i've had to date.
 
There are ao many mixed reviews of the 990, it seems either they work or they don't, most co plaints are people that cannot get them to star....i guess its a tuning problem or bad needle setting
 
Back
Top
✖
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock    No Thanks