R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Nitro On-Road

Reply
 
Thread Tools Search this Thread
Old 11-21-2005, 04:07 PM   #1
Tech Master
 
Join Date: Aug 2002
Location: Holiday, Florida
Posts: 1,810
Default Motor Tuning Question....

I have Sirio 3 port 12 and have tried another carburator with no luck...

When I get the engine hot and run it wide open for a couple seconds it seems to 'stick' at half speed then idle down. I have redone the linkages and they are going to neutral fine. I don't think the issue is there becuase even if I hit the brake its still rev'ing.

Any ideas? Thanks!
RCThunder is offline   Reply With Quote
Old 11-21-2005, 04:16 PM   #2
Tech Master
 
onnetz's Avatar
 
Join Date: Apr 2004
Posts: 1,727
Default

hard to say from the given info.. what temps are you getting?
sounds like its too lean and detonating..
onnetz is offline   Reply With Quote
Old 11-21-2005, 05:08 PM   #3
Tech Addict
 
Join Date: Nov 2004
Location: KISSIMMEE,FLORIDA
Posts: 700
Trader Rating: 2 (100%+)
Default

RICHEN BOTH NEEDLES TRY TOP 1/4 TURN BOTTOM 1/4 TO 1/2 TURN YOUR RUNNING TOO LEAN. IF TOP END IS FINE JUST RICHEN BOTTOM END TO HELP BRING ENGINE DOWN TO IDLE
__________________
Ahhh the smell of nitro in the morning!
Brooklyn Hobbies Team Driver
[url]www.brooklynhobbies.com[/url]
Team Trinity
[url]www.teamtrinity.com[/url]
Gary Figueroa
GFIGUEROA is offline   Reply With Quote
Old 11-21-2005, 06:12 PM   #4
Tech Fanatic
 
AndyT 's Avatar
 
Join Date: Sep 2004
Location: Sydney Australia
Posts: 862
Default

Engine losing power as it gets higher in its rpm would indicate that its running too lean (lean bogging)....richen it out a bit.
Cheers
AndyT  is offline   Reply With Quote
Old 11-22-2005, 08:52 AM   #5
Tech Master
 
Join Date: Aug 2002
Location: Holiday, Florida
Posts: 1,810
Default

Thank you for your help!
RCThunder is offline   Reply With Quote
Old 11-24-2005, 10:06 PM   #6
Tech Elite
 
Join Date: Aug 2004
Location: Pole Position
Posts: 3,173
Trader Rating: 13 (93%+)
Default

this actually sounds like the clutch is grabbing
is this a centax style clutch ?
__________________
Serpent 748 TQ | GIMAR Engines
Walter RC HObby | www.walterrchobby.com.au
BlueRC | www.bluerc.net
mrgsr is offline   Reply With Quote
Old 11-25-2005, 01:28 AM   #7
Tech Regular
 
FF25510's Avatar
 
Join Date: Aug 2005
Location: Hong Kong
Posts: 489
Default

did you put on the O-ring between the carburator and the body?
FF25510 is offline   Reply With Quote
Old 11-25-2005, 01:48 AM   #8
Tech Fanatic
 
Join Date: Mar 2005
Location: Sydney, Australia
Posts: 948
Default Exception to every rule!

I agree with everything that was said above, but believe it or not, being excessively rich on the Low speed needle can also lead to an engine running on. If rich on the bottom end, rpm decreases & engine will stall. To combat this, some people turn up the idle on the carby (screw it in). As you come off the throttle, the engine still has a belly full of fuel and due to the idle screw (on the carby) keeping the throttle slightly more open than usual, this causes the eingine to run on.

The solution would be to return the carby to factory settings, adjust your trim on the radio, set your gap (throttle opening) to 0.5mm with the idle screw. Then you start tuning at the top (High speed needle), then the bottom (low speed needle) for response off the line, then adjust the idle accordingly.

p.s. I was told this by the Australian 1/8th scale champion last weekend,and he also demonstrated it to me. I had the exact same problem with my N12LL3.
Im not saying that this is definately the problem with yours, but its worth a try.

Hope this solves your problem!

Last edited by Rody; 11-25-2005 at 02:13 AM.
Rody is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
motor tuning question.... SteveJa Nitro Off-Road 10 12-31-2007 12:01 AM
Tuning Question ChrisE Electric Off-Road 3 05-21-2007 05:49 PM
SH .28 Tuning question Nickmind Monster Trucks 3 04-13-2006 09:47 AM
beginner questions re: car tuning and motor tuning! Captjono Rookie Zone 5 02-19-2005 12:01 PM
beginners question re: car tuning and motor tuning! Captjono Electric On-Road 5 02-19-2005 03:01 AM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 03:57 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net