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Author Topic: cmb motors & low nitro fuel  (Read 1064 times)

retro boats

  • Guest
cmb motors & low nitro fuel
« on: June 20, 2007, 01:30:32 PM »

high all
 have just bought a boat with a direct drive cmb 45 fitted.
 i wondered if anyone has run these engines on straight fuel or 5% nitro fuel
                         thanks steve


  • Guest
Re: cmb motors & low nitro fuel
« Reply #1 on: June 20, 2007, 04:40:16 PM »

Lowest that I have run them on is 10% nitro. They run fine on that percentage nitro but having said that I do not race my boats.


  • Guest
Re: cmb motors & low nitro fuel
« Reply #2 on: June 20, 2007, 06:04:55 PM »

Hi Steve
The CMB45 will run happily on either straight or 5%.  For the nominal difference in cost I prefer 5% for racing, but this is only to give a bit more low end grunt to keep the speed up round corners.
The main thing is to make sure the fuel has enough OIL in it.  If you're using Model Technics get Duraglow which is about 16% oil, don't use Dynaglow as it's only 10% oil so unless you add extra EDL oil (which I do) the engine won't last.
Any other fuel with 15 - 17% oil (straight, 5% or 10% nitro) will run fine.
For straight fuel set your head clearance to 16 - 17 thou and for 5% set it at 20 thou.


  • Guest
Re: cmb motors & low nitro fuel
« Reply #3 on: October 07, 2007, 10:29:45 PM »

the best fuel to use is model technics gx-5% it has the right oil etc and i can get about 3 years of racing out of mine before it needs work!
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