Let's talk gas/oil mix...

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Wasted wages

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Gas/oil mixtures only, let's leave nitro out of this one for now. And yes,, I realize that this is mostly a nitro site... but I trust you guys more than the other place..

I'm just getting back into boats and have a long time history of running nitro. I did have 1 gas mono with a CC modified motor that I just ran 87 pump gas with Mercury lube before I left boats for a few years..

Now that I have been getting back into boats, I am running more gas engines than nitro and I have read about people using more than just pump gas and specific oils for different brands/mods of engines..

some say stick with 87 octane...
some say burn 112C VP...
some say use additives...

Oil brands are all over the page..just loyalty or solid evidence to back up choices ?
Mixture ratios seems to vary widely too..50:1 ?
32:1 ?

So,,, Discuss what you are using for gas and oil mix in your engine and why you choose to run the blend and type fuels and oils that you do.

Try to keep it civil !!!
Go !
 
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RobertDoak

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You realize you are opening a never ending worm hole....
 

Mike Byer

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87 octane fuel, non ethanol and 8 oz of the Merc oil is all you really need for a Zenoah, Some of the Quickdraws need a little more octane. Everyone has an opinion on this but usually it's just something to argue about.
 

Mike Cathey

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Find somebody in your club/area whose stuff performs and is reliable and do what they do.
 

Ray Sametz

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Gallon of gas-8 ounces of Holy anointing oil and a pinch of garlic. Test with thumb on forehead. :rolleyes: I know, "Go away n00b!"🤣
 

Lamar_Huff

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Ask 10 ppl this question and you could potentially get 12 different answers!!! Our brew consists of 10 oz of Klotz Super Techniplate (w/ castor) per gallon of AV gas. We run the AV gas not for the higher octane, but because it has virtually no odor (so the trailer and workshop don't smell like a lawnmower repair shop)!

We are running higher timing now and turning these gas engines way beyond what the factory intended. We moved over to 10 oz of Klotz a year or so ago (from 8 oz of Mercury Quicksilver) after trashing a few engines is a very short period of time due to wrist pin bearing failures. The newer hobby specific cranks with oil slots/holes on both ends have made the dreaded bottom end crank bearing blues a much rarer occurrence, but it still happens from time to time.

Don't worry about the octane rating... you can't get the compression high enough on a standard Zenoah to make it detonate (unless you run about 15% nitroethane - but you didn't hear that from me). :cool: Like Mike says above, some of the Quickdraws (with removable head buttons) do require higher octane because they have smaller combustion chambers than the standard Zenoahs.

Later,
Lamar
 

LohringMiller

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We did a lot of fuel and oil tests over the years. My favorite was a series of fuel tests in an M&D Zenoah. As far as power, it doesn't matter what brand of oil or the octane rating of the "gasoline" you use. Even fuel cheating by adding nitro or running ethanol or methanol in the fuel won't help. The reason is that Zenpahs and their clones have low compression and fixed ignition timing. Most important, the pipe is designed for normal gasoline. See namba.com/content/library/propwash/2009/october.pdf

We also did some oil testing, especially on the CMB 35. Up to 8 oz per gallon increased power. More didn't increase power, but didn't hurt, at least up to 13 oz per gallon. The type of oil, even synthetic/castor blends, didn't keep the AAC piston and liners on the original CMB 35 from seizing.

Lohring Miller
 

Mike Byer

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I raced and tested a lot with Jim Allen, he kept his fuel in a dark glass jug with a cork and kept out of the sun. Something about a plastic jug wouldn't stand up. He never would share or tell what was in it, but you can bet that it was something special just like everything he had.
 

SayMikey

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10 oz of oil in every gallon of camp fuel I burn. No issues here
 

Wasted wages

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Seeing as I have a little drag racing background and experience, ( very little!! ) I always want to apply that the our boats, which doesn't always work out.
Will these little motors run on E85 or methanol?
has anyone ever tried it ?
 

Wasted wages

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So, what is the benefit of using camp fuel ?
Your talking about Coleman fuel right ?
isn't that stuff kinda low octane?
 

Danny King

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Seeing as I have a little drag racing background and experience, ( very little!! ) I always want to apply that the our boats, which doesn't always work out.
Will these little motors run on E85 or methanol?
has anyone ever tried it ?
You will need more compression and more fuel delivered
 

Paul Cooper

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Apr 2, 2020
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For my 1/5 scale Baja I have a OBR 34cc Reed case putting out 9.5hp. They recommend 28 to 1 fuel mix. I'm using Yama Lube. I also have Royal Purple 2 stroke oil. I use 91 octane and if I can find it ethanol free. But as someone else said you opened up a can of worms with that question. On the Large Scale Forum when someone asks this they usually get crucified .:D:D
 

john v

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87 octane with 8oz of maxima castor 929. this with regular maintenance (wrist pins) and my motors last a long time. i was told that camp fuel doesnt have all the additives that pump gas has and the carbs will last longer?
 

Wasted wages

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Jan 2, 2006
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For my 1/5 scale Baja I have a OBR 34cc Reed case putting out 9.5hp. They recommend 28 to 1 fuel mix. I'm using Yama Lube. I also have Royal Purple 2 stroke oil. I use 91 octane and if I can find it ethanol free. But as someone else said you opened up a can of worms with that question. On the Large Scale Forum when someone asks this they usually get crucified .:D:D
Flame away !!
I really find it interesting all of the different combinations people use and try to sort it out in my own mind what seems to be the best choice.
I never would have started this thread except for a conversation I was having with a well known and respected builder of our little motors the other night... he said what to run in his modded motors and it surprised me, so I thought I would start a thread to see what others are doing here as well...
 

Mike Byer

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Feb 17, 2002
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Everyone seems to have their favorite fuel/oil/ratio that works for them. Just something to discuss and see how other people think. It's just part of the equation to have a good time playing with boats. When they run all day and don't lock up it's a win. Take away the information you can use and leave the rest behind. I for one like to see the combos of fuel and oil that people think are the only one that will work and have a good reason why
 

Grimracer

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Dec 27, 2001
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Camp fuel 16:1 (oil band and type did not seem to play a large roll).. we picked up 3MPH and WAY more important is how the boat needled. SO SO nice to tune.
The motor ran cooler and were way less finicky!

Grim
 

Hydro Junkie

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I'm going to throw out a bit of chem on this one, to start. I've done some research and found that Coleman fuel and your off the shelf Naptha are almost the exact same thing. Naptha is highly flammable in the same way as Coleman fuel and costs less.
As far as octane, as we all know, octane is a rating given to fuels that ranks it's resistance to igniting. What was learned by our CMB importer, Stu, is that the CMB 27 didn't "wake up" unless it was fed 100+ octane avgas. You can find his posts on the subject in the gas forum
 

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