CMB Alpha 27 Info

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Blackout

Blackout

Well-Known Member
Joined
Sep 10, 2008
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1,610
I hope to have my Alpha 27 powered Envy ready to run for the first time in 1-2 weeks. I'm looking for any suggestions like initial carb settings, oil type and percentage, and fuel used. Also any other info that you think might be important for someone who is relatively new to gas. Most of my experience is with nitro. Also, is there anything to adjust with regard to the ignition system?

All info is appreciated.

I already plan to purchase some 100LL aviation gas. I'm hoping this will not be a problem at any of the local airports.

Thanks.
 
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Is there anything that CMB recommends? I avoid regular pump gas like the plague because of its additives and the chance of ethanol. 100LL shouldn't have those but I haven't tried getting any yet. I do know 2 guys that work at an airport that also run gas boats that said if I need any they'll get me some but it's a good 60 mile drive one-way to get it. I don't know how the local airports are but maybe a smaller one would be your best bet.

I've been running Honda HP-2 but that may be harder to find now, even at dealerships. I may go to Lucas synthetic 2-stroke mix next as O'Reilly's carries it and heard it's good stuff. I mix 8 oz. to a gallon, some go to 10 oz.

Leave the ignition alone. Just check the gap at the flywheel.

Mark Grim knows these engines well as he's helped Stu Barr with his also. He'd be your best bet for helping you set one up.
 
I see CMB recommends 98 octane with the newer head button. I used to run the 100LL for other reasons ,all the additives in car gas would make me sick by the end of the day. I was able to buy it from my local general aviation airport. I did buy some once at the race in Vegas. I just contacted the airport manager at the executive airport and he was great drove me out to the pumps in his official vehicle. Just remember running a higher octane than required raises exhaust temps.
 
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I purchased the engine from Mark Grim, but was hoping to get a forum thread going on this engine.... I'd like to hear from others on their personal experience with this engine. Any tech shared about this engine on the internet will only help CMB sales. Thanks!
 
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Great idea. Like Ron said Mark probably has more time on that motor than anyone in the USA. You should share Marks setup tips to get the conversation started. Found this on the CMB site.

NEW ARTICLE !!!

ART. C92804/1 HIGH PERFORMANCES HEAD BOTTON

Use this part as follow:

1) 98 Premium petrol only

2) NGK CR8HSA or CR8HIX spark plug

3) Set up advance of ignition to 1,2÷1,3mm before T.D.C.
 
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Hi There Blackout.......... PM sent to you
default_smile.png


Scotty
 
Craig,

I have about a gallon through mine now. All fuel mix is with 100 LL. Started with 12 oz Quicksilver oil added to 128 oz of 100 to break in. Now I am running Redline 2T oil (10 oz to 96 oz 100). Noticeable power increase with the Redine mix. I have the new style head in mine with .024" head clearance (2 shims). Learning about needle settings on carb and am getting close. Now I am having to readjust the hull (sponsons) to handle the power. Last run was at 78 mph and Mark Grim tells me I should end up around 83 to 85 mph. We plan on going out today or tomorrow and test again if the weather permits. Being a "Nitro Guy", I am sure getting an education on running gas now!

Stu
 
Stuart Barr said:
Craig,

I have about a gallon through mine now. All fuel mix is with 100 LL. Started with 12 oz Quicksilver oil added to 128 oz of 100 to break in. Now I am running Redline 2T oil (10 oz to 96 oz 100). Noticeable power increase with the Redine mix. I have the new style head in mine with .024" head clearance (2 shims). Learning about needle settings on carb and am getting close. Now I am having to readjust the hull (sponsons) to handle the power. Last run was at 78 mph and Mark Grim tells me I should end up around 83 to 85 mph. We plan on going out today or tomorrow and test again if the weather permits. Being a "Nitro Guy", I am sure getting an education on running gas now!

Stu
Click to expand...
Great info! Thanks. Keep me posted on any new info.
 
keep in mind that CMB is in Europe, and their octane recommendations are in RON, not (R+M)/2 like we use. 98 RON is the same as 93 here.
 
There has been quite a few changes sense this thread started. Best thing would be to contact Stu Bar for all of the details and recommend changes!
 
Yeah that’s what they told me also I never really could get a good measurement so I always go by amount of turns. Try to measure that in a boat between heats it just doesn’t work
 
Ya unless the carb is out well I guess depending on what your running it in it’s hard to get a good measurement. When I checked mine with this measurements it was really close with the needle setting I was running.
What are you running this engine in?
 
Should go good in a mono. I have a 28.5 I am running in a 1/6 Scale Hydro. I am running about those needle setting on 100LL av gas.
 

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