Glow Engines Discuss RC glow engines

OS 61 sf max carb problem

Reply
Old 11-12-2002, 08:23 PM
  #1
onrecess
Thread Starter
 
Join Date: Oct 2002
Location: Boca Raton, FL
Posts: 185
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default OS 61 sf max carb problem

I am running an OS61SF max on a TT fun fly extra. I got it used. The low speed needle is adjusted by an eccentric screw moving a fork. The fork was upside down (I think). There is a crescent cut out on the closed end of the fork. Does that face the high spd needle valve?
I replaced the needle which was broken off flat. I use a pitts muffler, and cannot seem to get a smoke trail, even when it seems too rich.
Oh, I am running a 11x7.5 prop. I posted in fun fly to ask if that is enough prop.
Thanks,
Tom
onrecess is offline  
Reply With Quote
Old 11-13-2002, 02:05 AM
  #2
jmercer52
 
Join Date: Mar 2002
Location: Rome, GA
Posts: 387
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default OS 61 sf max carb problem

Sorry, That doesn't sound like a stock carb to me. A stock carb should have the low speed needle on the throttle arm side right in the center of the barrel. the high speed needle is on the other side of the carb. I don't beleive I have ever seen a "fork" on a carb.....you sure have me stumped.
jmercer52 is offline  
Reply With Quote
Old 11-13-2002, 05:55 AM
  #3
Flyboy Dave
Moderator
 
Join Date: Mar 2002
Location: Pinon Hills, CA
Posts: 13,774
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default Is that the O.S. Type 7L carb ?

It goes like this.....
Attached Thumbnails
Click image for larger version

Name:	35386_5977.jpg
Views:	182
Size:	38.0 KB
ID:	22450  
Flyboy Dave is offline  
Reply With Quote
Old 11-13-2002, 12:22 PM
  #4
onrecess
Thread Starter
 
Join Date: Oct 2002
Location: Boca Raton, FL
Posts: 185
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default yeehaa!

Yep, that is the one. Your picture makes it clear the cut out is toward the needle. Thanks a heap!
Tom
onrecess is offline  
Reply With Quote
Old 11-13-2002, 04:02 PM
  #5
Bax
Moderator
 
Join Date: Apr 2002
Location: Monticello, IL
Posts: 19,479
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default OS 61 sf max carb problem

Flyboy Dave,

The main thing about your carb is the position of the slotted screw with the eccentric head. That's the one at the top of the picture. When the slot in the screw is straight up and down, your idle mixture is in the center of its range. Turning it clockwise will lean the idle mixture, and turning is counter-clockwise will richen the idle mixture.

If the carb's been disassembled, the mixture control assembly may have been installed at 180 degrees to the correct position. This will cause all kinds of headaches in running.

If your engine will throttle nicely from idle to top RPM, and has a good idle, then the assembly's installed correctly.

A smoke trail may or may not develop when the engine's running well. It depends upon the fuel used, the exhaust system, and the weather. You can have an engine running very well with little visible smoke. Depending upon the fuel, you can have a lot of visible smoke and still be running too lean.

Listen to the engine carefully, do the 'pinch' test while setting the engine. If you give the fuel line a quick pinch at full throttle and the RPM jumps a bit, you're rich of peak RPM. If it sags or stays the same, you need to richen the high-speed needle until you get a slight jump. Listen to the engine carefully when it's in the air, and adjust the mixture as necessary to allow for the RPM increase as the engine unloads.

We usually ran the O.S. Max .61 SF engines on our test stand with a 12x8 APC prop, 10% Omega Fuel, stock muffler, and an O.S. #8 plug. We'd see RPM in the mid- to high-11,000's. Any idle below about 2,700-2,800 was considered 'good'.
Bax is offline  
Reply With Quote
Old 11-13-2002, 05:31 PM
  #6
Flyboy Dave
Moderator
 
Join Date: Mar 2002
Location: Pinon Hills, CA
Posts: 13,774
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default onrecess....If you don't mind...

....I'll E-mail you the "Operating Instructions for the
O.S. Type 7L carb ".

E-mail, or PM me your E-mail Addy, so I can attach
the instructions.

Dave.

( Thanks, Bill....that's all good info )
Flyboy Dave is offline  
Reply With Quote
Old 06-22-2003, 09:25 PM
  #7
aou816
 
Join Date: Jun 2003
Location: beaumont, TX
Posts: 2
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default 7 l carb

hey flyboy, i would love it if u cound send me something to show me how to set the 7l carb. my e-mail addy is nowellracing@yahoo.com. thanks alot.
aou816 is offline  
Reply With Quote
Old 06-22-2003, 11:24 PM
  #8
Flyboy Dave
Moderator
 
Join Date: Mar 2002
Location: Pinon Hills, CA
Posts: 13,774
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default aou816....

....OK....I saw them just the other day....I'll scan 'em,
and e-mail 'em to ya'....
Flyboy Dave is offline  
Reply With Quote
Old 06-23-2003, 02:03 PM
  #9
Flyboy Dave
Moderator
 
Join Date: Mar 2002
Location: Pinon Hills, CA
Posts: 13,774
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default aou816....

....they're on the way....

Dave.
Flyboy Dave is offline  
Reply With Quote
Reply


Thread Tools
Search this Thread
Display Modes

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



All times are GMT -8. The time now is 05:31 AM.