CMB 21 RS Needle Assembly Problem

[sport hydro]

I have a CMB21 RS. At the pond today, I could not get the motor to stay running on the water. Put a Boras flow meter on the carb

and set the needle at 80. If I placed slight side pressure on the needl cap, I could get the guage to bounce from 60 to 90.

The "o" ring looks good but the needle seems loose and easy to turn. The motor is less than one year old and ran great last year. It is in a sport 20

hull, runnig a Y536/2 blade and cooper quite pipe set at 8 1/8".

 

[hydro rob]

I have the same problem with mine and I am serching for a replacement carb.

 

[julianconde]

well i have a a almost new CMB 21 RS if you aguys are interested

 

[DaveMarles]

This was my solution. Silver soldered the brass partr of OS radio needle to the CMB spraybar.



Dave

 

[Jerry T]

I have a CMB21 RS. At the pond today, I could not get the motor to stay running on the water. Put a Boras flow meter on the carb

and set the needle at 80. If I placed slight side pressure on the needl cap, I could get the guage to bounce from 60 to 90.

The "o" ring looks good but the needle seems loose and easy to turn. The motor is less than one year old and ran great last year. It is in a sport 20

hull, runnig a Y536/2 blade and cooper quite pipe set at 8 1/8".

Ed, I have a brand new needle assy like this and the flow bounces like crazy also.

I cut down a Russian remote needle assy(the ones CMDI sold) and mounted that on the carb.

Kind of the same thing Dave Marles did with the O.S. needle.

 

[sport hydro]

Thanks for the replies. I found an older CMB black carb with just the nipple assy, so I swapped it out and installed an OS remote needle I got from Brian

S. Took it to the pond yesterday and set the needle on the flow meter. The motor rev's great and has good throttle responce.

Jerry,

This is the sport 20 that Christina (my daughter) runs. Me and Brian had to richen it up to get it to were Chris could handle it.

See you at Shamburg.

 

[Jerry T]

Thanks for the replies. I found an older CMB black carb with just the nipple assy, so I swapped it out and installed an OS remote needle I got from Brian

S. Took it to the pond yesterday and set the needle on the flow meter. The motor rev's great and has good throttle responce.

Jerry,

This is the sport 20 that Christina (my daughter) runs. Me and Brian had to richen it up to get it to were Chris could handle it.

See you at Shamburg.

Sorry Ed, not going to Schaumburg, going to Evansville instead.

 

[Rokieboater]

So what's the issue. Has anybody figured what's going on with the carb. I am going to run this same motor next week and would hate to go thru the same issues.

Robert Holland

 

[Jerry T]

So what's the issue. Has anybody figured what's going on with the carb. I am going to run this same motor next week and would hate to go thru the same issues.

Robert Holland

I think the needles are poor design, even when they don't bounce around the adjustment range is very small.

My 2 cents.

 

[Stuart Barr]

This was my solution. Silver soldered the brass partr of OS radio needle to the CMB spraybar.

View attachment 19533

Dave

Dave,

Did you try the CMB valve not mounted on the carb? I believe engine vibration could cause a problem with fuel flow. Great looking valve and I hope it works.

stu

 

[sport hydro]

Stu,

On mine, the whole assembly has alot of side play in it. Both the needle and the third channel housing can move . The "O" rings seem to be a little undersized and causes a loose fit. As I said, I replaced the assy. with a nipple off an earlier CMB black carb and then put in an OS inline remote needle.

 

[DaveMarles]

This was my solution. Silver soldered the brass part of OS radio needle to the CMB spraybar.

View attachment 19533

Dave

Dave,

Did you try the CMB valve not mounted on the carb? I believe engine vibration could cause a problem with fuel flow. Great looking valve and I hope it works.

stu

Stu, A remote needle would have worked but I prefer the radio needle directly on the carb. The CMB needle worked well and I liked its fine adjustment but I didn't like the way the readings on the flowmeter jumped about when I touched the needle.

Dave

 

[BB Mods's]

So what's the issue. Has anybody figured what's going on with the carb. I am going to run this same motor next week and would hate to go thru the same issues.

Robert Holland

Have no fear brother, that carb will be just fine, what are you putting it in?

 

[hydro rob]

Does anyone have or know where to get a cmb21 carb with just the nipple on it? or can that pice be bought and bolted on? thanks

 

[BB Mods's]

I just cut the stock unit's down and silver solder them shut.

 

[Rokieboater]

So what's the issue. Has anybody figured what's going on with the carb. I am going to run this same motor next week and would hate to go thru the same issues.

Robert Holland

Have no fear brother, that carb will be just fine, what are you putting it in?

ONe in a JAE the other in a new SGX

 

[mattb]

we have two cmb 21 rs , one inboard and the other is an outboard. we have raced them both for two yrs. with no needle slop. you should look at your motor while it is running to see if needle is loose if so then replace the o ring. matt