OS 9 b

[michael faszcza]

thank you it fired up and runs good at idle and revs nice on the bench .now to figure out why the throttle servo is dancing ,it only does it when running thought it was metal to metal contact from the shaft safety collar loose but that's not it ill have to search deeper for any more metal to metal and im gonna try new batteries I cant think of any other reason why

 

[Ray Sametz]

thank you it fired up and runs good at idle and revs nice on the bench .now to figure out why the throttle servo is dancing ,it only does it when running thought it was metal to metal contact from the shaft safety collar loose but that's not it ill have to search deeper for any more metal to metal and im gonna try new batteries I cant think of any other reason why

Mike, check the pipe inside the coupler, if it's hitting the header can cause a glitch.....

 

[michael faszcza]

will do thank you

 

[Ray Sametz]

Another question, what's the small set screw on the high speed needle used for?????

 

[glenng]

Ray, I have had a lot of the 9B carbs but none had a set screw on the high speed needle- perhaps someone added it.

 

[Ray Sametz]

?????

 

[El Zorro]

Ray,

I believe that holds the needle in the body of the needle valve. If you loosen the screw, just the needle will come out of the body. Don't think there is a flat ground into the needle, so if you do loosen it to Loctite the set screw, take a measurement of how far the needle is sticking out of the body. I might be wrong on this, but it's been a while...............

Dick Tyndall

 

[Don Ferrette]

Ray,

I believe that holds the needle in the body of the needle valve. If you loosen the screw, just the needle will come out of the body. Don't think there is a flat ground into the needle, so if you do loosen it to Loctite the set screw, take a measurement of how far the needle is sticking out of the body. I might be wrong on this, but it's been a while...............

Dick Tyndall

That set screw is left over from airplane applications. If you look at the knurled end of the needle you'll see a hole on the end that allows one to use an extension rod to get the needle adjustment outside the fuselage. The set screw is what anchors whatever extension rod one chooses to use.

 

[Ray Sametz]

Ray,

I believe that holds the needle in the body of the needle valve. If you loosen the screw, just the needle will come out of the body. Don't think there is a flat ground into the needle, so if you do loosen it to Loctite the set screw, take a measurement of how far the needle is sticking out of the body. I might be wrong on this, but it's been a while...............

Dick Tyndall

That set screw is left over from airplane applications. If you look at the knurled end of the needle you'll see a hole on the end that allows one to use an extension rod to get the needle adjustment outside the fuselage. The set screw is what anchors whatever extension rod one chooses to use.

Yup, there's a hole in the end for an extension. Makes sense.

 

[El Zorro]

YEP..........my bad. Just looked at a new O.S. 40A carb and came to the same conclusion as Don explained above. Some where in past years I did run across a needle valve as I explained in my earlier post. Just wasn't one of these O. S. needles. Cool idea, though.............

Dick Tyndall

 

[Ray Sametz]

YEP..........my bad. Just looked at a new O.S. 40A carb and came to the same conclusion as Don explained above. Some where in past years I did run across a needle valve as I explained in my earlier post. Just wasn't one of these O. S. needles. Cool idea, though.............

Dick Tyndall

Air Biscuit, wish I new what you forgot about this hobby!!!

 

[michael faszcza]

that was it thank you

 

[moparbarn]

See ya sunday at the t&t, mike. George & i will help you get it right, sounds close now.

 

[Keith Halverson]

What makes the OS9B so much better than the original CMB carb?

 

[Ray Sametz]

What makes the OS9B so much better than the original CMB carb?

Keith, I should have said this was for an 1/8 scale. Your question I'll leave to the guru's.

 

[Samuel Hagan JR]

What makes the OS9B so much better than the original CMB carb?

I would like to know also.

 

[Duck899]

The older CMB 67 greenheads came with a lame carb that had no low end fuel adjustment and were better suited for riggers. Guys would replace them with OS9B's because of this and the OS flowed more air on the top end. Out here in the northwest, the guys will crawl along at 5-10mph during mill to get the inside. The OS carb allowed that to be done. The new CMB carb now has a low end needle and works as good as the OS unit. I have the CMB carb on my Bardahl and it will crawl along and then instantly get up and go for the start of a heat race.

Here is a video showing how slow the boats go from 15 seconds to the start.

https://www.youtube.com/watch?v=d1i5lD5ZrRU&list=FLulcj8nLfOEv2cBSw7B05FQ&index=44

 

[Keith Halverson]

What makes the OS9B so much better than the original CMB carb?

Keith, I should have said this was for an 1/8 scale. Your question I'll leave to the guru's.

No Problem and thanks!. Sorry to take your thread a bit sideways and appreciate all the answers to questions unasked. If I may,,just one more from the gallery. The 2013 CMB carb received the new low end needle? Because,,my heavy boat is going to need that.

Thanks ahead of time.

 

[David Bryant]

The older CMB 67 greenheads came with a lame carb that had no low end fuel adjustment and were better suited for riggers. Guys would replace them with OS9B's because of this and the OS flowed more air on the top end. Out here in the northwest, the guys will crawl along at 5-10mph during mill to get the inside. The OS carb allowed that to be done. The new CMB carb now has a low end needle and works as good as the OS unit. I have the CMB carb on my Bardahl and it will crawl along and then instantly get up and go for the start of a heat race.

Here is a video showing how slow the boats go from 15 seconds to the start.

https://www.youtube.com/watch?v=d1i5lD5ZrRU&list=FLulcj8nLfOEv2cBSw7B05FQ&index=44

so, ultimately, sounds like the O.S. 9B would have a slight edge over the stock CMB .67HR/.80HR carb? Being that the O.S. 9B flows more air at top-end (and could even be improved with bell-mouth mod)? Even though the current .67HR/.80HR has updated low-end needle?

I have brand-new CMB .80HR engines (green-head & blue-head)

 

[Ray Sametz]

The older CMB 67 greenheads came with a lame carb that had no low end fuel adjustment and were better suited for riggers. Guys would replace them with OS9B's because of this and the OS flowed more air on the top end. Out here in the northwest, the guys will crawl along at 5-10mph during mill to get the inside. The OS carb allowed that to be done. The new CMB carb now has a low end needle and works as good as the OS unit. I have the CMB carb on my Bardahl and it will crawl along and then instantly get up and go for the start of a heat race.

Here is a video showing how slow the boats go from 15 seconds to the start.

https://www.youtube.com/watch?v=d1i5lD5ZrRU&list=FLulcj8nLfOEv2cBSw7B05FQ&index=44

so, ultimately, sounds like the O.S. 9B would have a slight edge over the stock CMB .67HR/.80HR carb? Being that the O.S. 9B flows more air at top-end (and could even be improved with bell-mouth mod)? Even though the current .67HR/.80HR has updated low-end needle?

I have brand-new CMB .80HR engines (green-head & blue-head)

Dave, the 9B I have on my CMB 80HR is bored out to .470. Have not tried it yet, hard water. Single F hydro.