I just picked up one of these used off of an auction site to remain nameless. I just received it and was sitting down checking it out. its got a little bruise on the top and front (toward the carb) but that doesnt' look bad at all just a little scrape to the fins actually. The real thing I'm wondering is when I turn this engine over by hand it doesn't seem to have a lot of pressure when the piston travels up. the slower I turn the engine the less pressure it has. I'm wondering what I need to do to check and see if this engine is ok. The guy stated that it ran fine and was a used engine but it was strong. I haven't ran it yet because I wanted to get a little advice on it. Thanks in advance
Brandon

Brandon,

Most current engines in this size class are ABC/ABN in construction.
They feel like they have better compression and sealing, especially if compared to a "dry" ringed engine.

Your K&B, unless it is the 6.5 RE, is probably a ringed engine. There was an ABC version too, though.

ABC engines feel more compressed, partly because of the tapered cylinder bore, that is tighter at the top than at the bottom of the piston travel.

It is also possible the engine is worn out...

It may be ill advised to buy a used engine, without seeing it run, unless the seller can be trusted.

Thanks for the fast response. I don't suppose a pic or 2 would hurt. I'll try to post em incase it this aids in any more advice. BTW if anyone can help me nail down exactly which engine it is I'd appriceate that.

I'm sure someone will know the exact model number but it's a cross flow (loop scavenged, call it what you will, but non Schneurle ported) engine and uses a Dykes ring. This type of ring relies on combustion pressure to give a good seal so they always feel worn out when turned over by hand and can even be difficult to hand start sometimes. Once running though, this type of ring is very effective.

Most K&B's have a serial no. on the mounting lug you can post and someone will know. Also.. you don't need to check it... just start it up. These are probably one of the best "deals" on ebay. They're cheap and reliable and if you dork it. Go buy another. Plus it's not made by communists.

Wow 3 replies in lest then 30 mins in the middle of the night. I love this site. Thanks for the info guys and keep it coming if you got more to add.

Brandon

It appears to be a model 4011 from the early 90s. Earlier models used a different carb and later ones had a remote needle. The explaination of the dykes ring is correct. Put it on a bench and test it. It should turn between 11,800-12,800 with a 10x6 prop. Not a powerhouse but a good reliable engine with a solid history.

That's the very early model 4011. Mine had/have the smooth face carb before they switched to Perry carbs. downunder is correct that they have to be flipped fast in order to feel any good compression. Only sure way to start it is with the electric starter and an idle bar plug.

Brandon,

If you can post a well lit photo, peering down the exhaust stack, at the top part of the piston, It will help us ascertain the engine type.

I think yours is one of the later versions, but that doesn't mean it's anywhere near new. The good news is they are almost bullitproof and run forever. if you want insurance, watch the auction and get a ring for it. You probably won't find one at the hobby shop.

I am very fond of these engines. I had one many years ago in a Kadet. When the Kadet had the wing knocked off in a mid-air the fuse came in like a lawn dart onto hard clay, shattering the engine. I sent the pieces to K&B and they sent a new engine at no charge. The replacement engine still runs fine today.

jess

Dar Zeelon I wish that I could get another pic of the engine. Unfortunately my new computer and my old camera don't seem to be getting along. I got those 2 pics from the auction where I bought the engine. The number stamped into the mounting lug is 0069241 if that helps. If your looking at the engine with the prop shaft pointing at you theres a small screw at the 10 o'clock position other then that the only other components on the carb are the throttle, needle valve and where the fuel line hooks up. hope this description helps. Thanks guys I really enjoy all the info. I'll just have to crank this baby up and see how she does.
Oh and one more thing I got this K&B 61 also. Seems to be fine can't wait to put these in planes
Brandon

Brandon,

I was aiming to see what the piston looks like, from the side; if it has a ring, near the top, or at the top of it.

BTW, this engine has had a bad crash. The whole front of the cooling fins on the head is eaten up.
It seems to have crashed on a hard surface.

Big D:

The first pictures you posted were from about 1987 or 1998, with the K&B carb and direct needle mounting. If it had the remote needle then the date would in the early 90s to current. The later post shows the same type 4011 engine in an earlier version, around the early to mid 80s, with the Perry carb.

All your illustrations are the type 4011, which is a current engine, and except for carb differences they are all the same.

Bill.

Dar: (and BD):

All the 83xx and 4011 K&B engines (early and late type 0.40 engines) have Dykes rings. Compresion is normally low at hand cranking speed. Nothing wrong.

Bill.

just to clear things up the second engine is a .61.

Your .061 was designed by Clarence Lee even before K&B owned the design. Yours is an early example with the perry carb. They later had some with an irvine carb then the K&B Block carb then the finned carb as on your .40 then the finned with remote needle. The current incarnation of this engine is still in production although probably not for long. It was announced that the twister will be discontinued and a new conventional head ABC .61 will be introduced.
These engines are very powerful for and engine in the .40-.46 weight class. Their power is very low for the .60 size class but since they are light and run so reliably they have been well accepted for a long time.

By the way: This engine also was involved in a crash or similar event as the muffler should bolt on not strap on.