stunthanger.com
Engine basics => Engine set up tips => Topic started by: David Ruff on March 22, 2018, 04:02:20 PM
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I have a new and never run Fox .36 slant plug engine.
Do I need to run the 29% castor in this or can I go with something more modern?
Photos are here for ID of engine.
Planning to mount on my Corehouse Gotcha Streak III.
(https://i.imgur.com/dB09EMsh.jpg)
(https://i.imgur.com/o6JPlgch.jpg)
(https://i.imgur.com/KnWbZzih.jpg)
(https://i.imgur.com/psHuLJVh.jpg)
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Dave,
Since this is an Iron P/C do the break-in with 5% nitro and at least 25% - 28% total oil. I would use a 9x6 prop. Due short rich runs for the first 20 - 30 minutes, pinching the fuel line occasionally to bring it to a burst of 2 cycle. After that you can either fly it rich for another 30 minutes or run it on the bench till it hold a rich 2 cycle without sagging. Once you get to this point you can bump the nitro to 10% and use 25% total oil (50/50).
Best, DennisT
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I have a new and never run Fox .36 slant plug engine.
Do I need to run the 29% castor in this or can I go with something more modern?
Photos are here for ID of engine.
Planning to mount on my Corehouse Gotcha Streak III.
(https://i.imgur.com/dB09EMsh.jpg)
(https://i.imgur.com/o6JPlgch.jpg)
(https://i.imgur.com/KnWbZzih.jpg)
(https://i.imgur.com/psHuLJVh.jpg)
David
NO do not use 28% castor you will ruin the motor faster, as you will with about any motor, use 1/2 to 1/4 synthetic and make sure you have at least 25% oil total, Break in very rich, almost sloppy rich to start then put the motor into a 4 stroke that has lots of smoke blowing, do this for 1 to 2 runs, after that if the motor feels good, not tight, then run in a 4 cycle with pinching the tube, or turning the needle so it bleeps into a 2 cycle, you want to, at this point, start to heat the motor up more, so it breaks in near the running speed.
I use a 10 x 3 prop for break in, or a 11 x 3 will work well
Most of these needed 10 to 15 tanks to do your breakin .
I have a n article pinned at the top of the forum you should read, care and Feeding of the stunt engine
Nitro percent will not matter for breakin , but no need to waste money using high nitro fuel, I use 5%
Also I had boxes of these, as I used them for Stunt SPORT and Slow Combat, both in 29 and 36 size
Randy
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So what percentage do you try? For motors like Fox .35s, OS Max 35s or the old McCoy’s and K&B’s, use a fuel with 26 to 28% oil content; preferably half castor and half synthetic, up to 75% castor is OK. These motors have very small bearing surfaces, and are subject to much wear and heat, most are all plain bushing motors and most have unbushed rods. They need a lot of oil to help cool the engines. Since these motors run hot, they need extra oil to keep them lubed,clean, and to carry out heat . If you have one of these that is in very good shape but, is just starting to get some brown or black varnish plating on it, the synthetic mix will clean it up for you, resulting in increased life. Do not use the synthetic blend in an old motor that has a lot of time on it with all castor fuels; the synthetic will remove the castor varnish off the piston and sleeve and will in some cases, leave you with the worn-out motor that had to start with. Also always try to NOT use prop shaft extensions with these engine, as it adds a lot of wear on the crankshaft bearing.
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Thanks, guys. I have basically been breaking in like Randy says. It runs good. I did dump some 20/25 in for a short run. Had to open the needle almost to the point of removing it to keep a 4 stroke run. LOL.
But it is OK.
Went back to 10/23 and it likes it.
I will continue to break in on bench. Then mount on the Gotcha Streak III.
It is a monster engine; lots of power there.
I am using a 10-5 prop to break in.
I can see how it would swing a larger prop.
Interesting engine.
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I read somewhere this has a spraybar with two holes? I have to check it out.
It was loose when I first started it. I tightened up the fitting and oriented the hole like most, down.
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Amazing what happens when you remove the spray bar and find it is clogged, then clean it.
This thing runs strong and starts easy.
I am beginning to think it is too much engine for a 30 oz Gotcha Streak III stunter.