Cmb 1.01 running problems

[Todd c winnega]

I find it imposable to dial this motor in. I have run the remote needle valve from2 turns out all the way to 4 1/2 turns out and the motor really runs about the same. And thats like a box of crap. I have run cmbs before and never had a problem like this. Its getting so frustrating that I am about ready to pull this brand new motor out of my boat and sell it and put my QD 25 high output back in at least thats a reliable motor.

 

[SayMikey]

You have to break this motor in slow like over a gallon of fuel. Otherwise its going to toast rather quickly........Is it box stock? Nitro % pipe length boat type

 

[dwilfong]

Well where do we start.

Is the eng stock as it came in the box?

Has the rotor clearance bin adjusted to .002?

Has the head button bin opened up to make the chamber larger?

Has the head clearance bin checked and adjusted?

Answer these question and we can put you on the right track.

David

 

[steve wood]

Well where do we start.

Is the eng stock as it came in the box?

Has the rotor clearance bin adjusted to .002?

Has the head button bin opened up to make the chamber larger?

Has the head clearance bin checked and adjusted?

Answer these question and we can put you on the right track.

David

rotor clearance done,head opened up,head at .015,188° exhaust,liner skirted,rotor at 211° and 63°.
number of turns on the needle is irrelevelant.start very rich then lean it down a click at a time(you do have 3rd channel,i'm assuming).if the pipe is too long,too short,or the wrong pipe,you will have a tough time.how much does the boat weigh,i know it's a gas boat,and if it's heavy you may need to prop way down for the nitro motor.what prop did mark send you.

 

[BigChuck]

Well where do we start.

Is the eng stock as it came in the box?

Has the rotor clearance bin adjusted to .002?

Has the head button bin opened up to make the chamber larger?

Has the head clearance bin checked and adjusted?

Answer these question and we can put you on the right track.

David

rotor clearance done,head opened up,head at .015,188° exhaust,liner skirted,rotor at 211° and 63°.
number of turns on the needle is irrelevelant.start very rich then lean it down a click at a time(you do have 3rd channel,i'm assuming).if the pipe is too long,too short,or the wrong pipe,you will have a tough time.how much does the boat weigh,i know it's a gas boat,and if it's heavy you may need to prop way down for the nitro motor.what prop did mark send you.

What Gas hull Is it. If the boat is plowing and will not get up..? could be CG. have found from my own experience using a gas hull with a 101 that the CG is Critical. So much so that I put the gas motor back in the hul and it works great.

 

[Todd c winnega]

I had steve wood do my mods. Its in an insane boats G4 hydro weight is approximately 10.5 lbs and a 27 17 prop with 8" of pitch. And the pipe length is 11.5" to the start of the flat on my macs 15cc pipe.

 

[BigChuck]

Pull the pipe and go down one prop size..................get it going and tune from there.

 

[dwilfong]

Use a stock prop first to find out what it likes. cup will kill the RPMs. It is not a gas eng let it rev.

Try a stock 2716/2 15 rake and see where you are at.

David

 

[Buckshot]

27 17 prop with 8" of pitch. And the pipe length is 11.5" to the start of the flat on my macs 15cc pipe.

Who did this prop with 8" of pitch? That sounds pretty steep. Try backing down to a stock 2716 or [email protected]" or [email protected]".

That boat should fly with a 1.01!!

 

[ALLAN YUEN]

Did you check on " CMB" 3rd needle or single neede both sometime block from rust inside . will you look open at it another your what kind of tank( metal or plastic or bag) at boat

 

[dwilfong]

A RS 1.01 is not like any other CMB eng. It takes time to tune them. when you put a smaller prop on be careful if it comes a live and gets up on pipe.

Thy have to be run rich or it will melt down and quick. Don't get happy finger with it and don't over rev it with a small prop.

If you rub it the right way the genie will come out.

 

[Todd c winnega]

You can get the prop from Das Boata .I had suspicions about the needle valve from the start is it normal to have to use a wrench to change the needle setting? I am currently waiting for a new one from mike hallam. I cant use a needle with a third channel because I dont have room in the radio box for the servo.

 

[P THOMAS]

What size is the fuel line? Install large or extra large lines, If the needle adjustments dont seem to matter it could be not flowing enough fuel thru smaller lines. Learned that on Mac 67 once.

 

[dwilfong]

Todd

I would strongly recommend a third channel needle like a Bob Violet. It dose not take a very big servo to run the needle. Any micro servo will work.

With out this you are playing Russian Roulette.

When it comes on pipe it will go lean if the needle is not right and it will melt the piston. 50% nitro will give you the result you are looking for but it is harder to set the needle. 40% will give good power but you may not pull the prop you want at RPM. A nitro eng needs nitro to gain the power.

 

[Piston1]

Todd c wennega, if you got good fuel, good needle, good tune pipe, good fuel tank, motor tuned by Mr. Wood, good hull not beat up to pieces your boat should be a rocket like Chuck said, provided you have the correct prop. If you have all of the above then try to link up with a nitro club we will help you. Send a picture.

 

[Don Ferrette]

Todd, you are definitely over propped. As others have mentioned I would prop down to something like a 1667 @ 6.0"- 6.5" to get started. The prop you are trying to run is a typical gas prop you'd see on a 27-29cc motor, yours is a nitro motor almost 1/2 the size (16.5cc). Granted the hp numbers are there but the torque is not, pull the pipe to 12" to the beginning of the flat band on the pipe and prop down. Richen the motor up until when you stab the throttle on the starting bench from idle there is a stutter/stumble in the response before it revs up, that should get you fairly close since you don't have 3rd channel mixture (you can't stuff a mini servo in that radio box somewhere?). Also like others have said pay attention to the mixture when it runs, keep it on the rich side and you can start to work the pipe length in a little at a time. Even when you get it going I think you'll find that 2717 @8.0" will be better suited on a gas boat/motor combo. Those prop numbers would be rather stout even for a properly set up nitro rigger and the G4 is probably a couple pounds heavier, the 1.01 will need to get it done thru more rpms . You get the prop and pipe right and that boat should haul tail. B)

 

[Todd c winnega]

Problem solved I put in a new os needle set it at 2.75 turns put on a 2614 and the boat took off like a missile. It hit 85.9 mph. I had a gallon of fuel burnt up with the motor before it even came up on pipe. Now that my fuel issues are nailed down is this motor broke in and ready to be run hard.

 

[steve wood]

thanks guys for helping him out. i thought it was something simple

 

[Todd c winnega]

Yea thanks a bunch. I will try to get a video posted soon for all to enjoy.

 

[Todd c winnega]

Are there any boat clubs in wi? I only know one person who runs around here and we grew up running boats. And thats about 25 yrs now. Time flys when your haveing fun I guess.