BobH

My Feedback: (2)

Thats what I'm thinking. The engine runs well and the ultimately heats up .. I let it cool off and restart.. It's getting better.. slowly.

Dad_Roman

Remember to prop by hand in reverse rotation. This will open the exhaust valve first and let the (excess) oil out.

Refer to videos of B-17's before start up (been there done that)


Lars....."Whew"

Tom.....Some Robinhood vid would be nice

cymaz

Like I said, I did mine by the book. These radials demand looking after, though not high maintenance, such an engine does need a bit of pampering. I'm not complaining as it rewards me with loads of power and a beautiful sound. I'm very particular about after run procedures and using after run oil etc.
You don't but one of these beauties every day!

I take the bottom two plugs out and let the excess after run oil drain out, before start up checks. Then clean off the plugs by lighting them up for a second or two.

redball8

My Feedback: (128)

First runs should only be for 5 minutes or less - otherwise the engine will overheat, unless you have a cooling fan pointed at it. Mine broke in enough to hold glow on all cylinders after an hour, and could set the low end after two hours. Spent the last (third) hour trying different props, to hold down the rpm - figure it'll gain 10% in the air, so 6,000 max is ~5,400 static (on the ground). That'll depend a bit on the drag of your airframe & prop selection.

BobH

My Feedback: (2)

It's beginning to hold glow now. I'm taking it easy because it still has a tendency to over heat. Hopefully with time that will go away.
FYI I'm using the standard exhaust.

BobH

My Feedback: (2)

I should ask, I can run with out glow until I get over say 3500 rpms. Then the engine balks. My guess is that its not run enough to run wide open with out glow yet.

Dad_Roman

With all information it sounds like its hitting a lean spot to me (or maybe lean overall) but I will let one of the other guys chime in.

BobH

My Feedback: (2)

Not sure about "lean" I richen it up and it doesn't seem to make much difference.

Dad_Roman

Sounds like we have a problem......and will need some input from the others.

redball8

My Feedback: (128)

Hmmm. Have to agree that it sounds like the high speed needle is too lean. What fuel are you running? If it has too much oil it'll be thick, and the carb may not be able to feed enough fuel to the engine at high speed. Any muffler pressure to the tank?

BobH

My Feedback: (2)

No muffler pressure. The straight stacks don't allow for any. Oil is 9%. I mixed pure methanol 50/50 with Wildcat 2-4cycle mix 5% nitro.
I guess possible the fuel is getting "old".. that would effect things..

redball8

My Feedback: (128)

Not sure about old fuel - it doesn't really spoil. Perhaps tank position is too low? And wonder what prop you're using?

BobH

My Feedback: (2)

The prop is a 24x8 or 24x10? Id hafta look. fuel can degrade over time. This i know for sure. the tank isnt to low.. Its nearly even with the carb.. its all on a test stand.

Maxam

My Feedback: (62)

Try to richen the LOW needle. Can cause upper mid leaness. -Tom

BobH

My Feedback: (2)

Ran the engine this evening. The engine would run at 5100 with the glo on.. Turn off the glo and it would falter. So I leaned it thinking it was too rich. It was and ran close 5000 with the glo off.. So I'm getting there..
I'll get the Hi speed dialed in and then work on the low speed setting.

Cattledog

another thing to keep in mind is you might have debris in the needle areas of the carb. This can cause some confusing results when tuning.

BobH

My Feedback: (2)

Question, My needle valve retainer spring has some how broken. I'm talking about the one that is a friction fit arm that sits against the grove on the Carb. Needle Valve to keep it from rotating.
I don't see this as a part on the Evolution site or the Horizon Site.
Any Suggestions for a replacement?
I might try one from one of my other engines to see if it works, I'll let you know.

FYI. the engine is now running near 5000 with no glow assistance over half throttle. It's getting near broken in I think.

slskn

My Feedback: (4)

Hello Bob H if you have enough room try using a quarter inch piece of fuel tubing that would wrap around the needle valve body other words put the fuel tubing over the threaded part of the body screw the needle valve into to it

BobH

My Feedback: (2)

I took a piece of brass tube and cut it to the right length. Then I took the old "spring" portion and soldered it to the Brass Tube. The Brass tube was just a slip fit so I cut a slot in the tube lengthwise to pinch it and reduce the diameter. Everything now works great

tsnaylor1964

Okay, new member here. Been lurking in the shadows for some time learning about my evo 77 from some great contributors like maxum and others. Love my 77 and it runs and sounds beautiful. Pulled my asp 160 twin off the j-3 cub and installed this radial on her and boy, it is cool. 20x10 zoar prop, 7% evo oil with with methanol and no nitro. Use onboard glow with 4 D cell 10000 mha rechargable batteries wired for 2.4 volts switched with servo on 25 amp toggle. Like maxum, these engines have brought me back in the hobby after a 30 year absence. Hope this forum stays alive, would love to share info with others who enjoy these nice motors.
Tom

Maxam

My Feedback: (62)

Hey Tom, That prop is way too small!!!! Use a 22x12 or 24x 10. Even though Cubs use a flat four did you guys know some of the earliest Cubs used a 3 cyl radial? -Tom MaxAm

pappy 883

My Feedback: (2)

That Cub looks really cool with the radial out front. Like a real badazz Alaskan bush plane.

tsnaylor1964

Hey thanks Pappy. I was anxious to get the Evo 77 flying after six months running it on the bench and breaking it in. I first tried it on my Howard DGA-15 but at 24 pounds and 5700' elevation I could not get it off the ground. So I pulled the ASP 160 twin off the Cub and the rest is history.
What radials are you flying?
Tom

pappy 883

My Feedback: (2)

I have a evo 777 that I started to break in about a year and a half ago, never finished .
The plan was to put it in a old Byron F4U Corsair kit , also sitting idle.

tsnaylor1964

Maxam,
I bench ran and did the break in with a 24-10 prop but that was near sea level elevation. I fly at our ranch at 5700' elevation and it would not get more than 4850 rpm, even leaned out. I experimented with different sizes and pitch props and was able to get the best performance with the 20-10 zoar and 6050 rpm. Anyhow, I have a good excuse to buy the evo 99 for my Howard DGA-15 which is much heavier than the cub with less wing area. Thanks for all the great info and tips on running these beautiful engines, I learned a lot just reading your posts.
Tom