I have an AP 061 wasp that doesn’t run well. It will run at wide open but it will not throttle well and will not idle. When the throttle is reduced it will just quite. It doesn’t rev up a lean out or get rich it just stops.

This is a stock engine with no modifications. Are there any modifications that I can do to get this engine to run well?

Just keep running fuel through it at wide open throttle. Hopefully, it just needs to be broken in more.

David

What rainedave said.

My wasp took a LONG time to "come around". Fuel used was 10%nitro with 20% straight castor. Allow cool-down between runs, as per the instructions.

Mine took about a quart before it settled down, now it idles quite nicely. Bear in mind that these engines do NOT tolerate running rich. What normal engine would consider 'just right' isn't lean enough for these...too lean won't work either (one click either way will make the difference).

You also might want to check that there are no air leaks around the throttle.

George

Also check around the head and plug for leaks. The AP head shims are very poor quality (mine appears to be made from a recycled beer can) - if its leaking badly, you may not be maintaining enough compression at low RPMs to run.

I've got a few that had the crankcases wear out prematurely. Kind of surprising that they wore out sooner than a Testors .40 could.

It's also a good idear to put a piece of fuel line on the NVA (they tend to leak there).

And you must use the best size prop for your engine, too big and it will not run cleanly, I mean it will not rev out to the max, it will get hot and bothered. One of mine runs well on the 5.75 / 3, the other will pull a 6 / 3. Also I use 16% nitro, these are great engines in my view.

I'm afraid CP is right on the mark with the crankshaft issue... After well over 100 flights on my AP .061, the crank is beginning to get loose in the case. I can't wiggle the crank side-to-side-up-down a whole lot, but it's definitely wearing faster than I expected.

Mine seemed to run well right out of the box, but like others have suggested, the needle setting is "weird", almost counterintuitive, and the head gasket/shim was a joke. But hey, it still runs nicely on Morgan's Omega 15% with four ounces of castor added to the gallon. The little fella has served me well, and I imagine there's still a bunch of life left. Heck, I'd probably buy another (oh wait, I already did). I just wish the Chinese didn't copy Norvel's lame muffler attachment...

I've owned three Wasps and all of them had sloppy crank fits from the get go. Very disappointing considering that the cases are brass/bronze bushed. Mine throttled fairly well. I went to improve on this by re-bushing the case on one but that strategy made throttling worse. The fix was adding an adjustable airbleed.

Also, you may have a bad plug. What you describe, I've seen many times and swapping in a new plug was the fix.

There are a couple of "feel" checks that the experienced 1/2A engine users do that take 30 seconds. Crank fit and cylinder leakage.
A really well fit engine will allow the piston to bounce back and forth between TDC and BDC when you smack the prop. There won't be any axial play as you forcefully turn the prop. The cylinder should remain pumped up for at least 3 seconds after you bring it up to TDC, hopefully much longer.
A soda straw, can of water, duct tape and your breathe are all you need to quickly and definitively chase down crankcase air leakages.

When your Wasp .061 crank to case clearance got too large to run properly, did you just buy a new case and were "good to go" or did the crank wear also, needing replacement?

Mike

The wear in the crank to case fit was built in on all three that I owned. Close examination will reveal that the bore of the case is not precisely reamed or honed, but simply bored out on a lathe. Sloppy from the get go. This can give you a few "free" hundred rpms but at the expense of much fuel loss out of the front end. Run your engine and put your hand in line with the prop arc. Keep it at a safe distance and you'll get this cooling effect on your hand. That's raw fuel spraying on to your hand. In my opinion, the Wasp would be a great little engine if they would just fix this serious flaw. I've had them putting out nearly as good as a Norvel Revlite.

Hi!
I would also like to ask the owners of that little engine, whether they have figured out the metallurgy of the piston and cylinder set. Is it an ABC an ABN or an AAC? It is strange because it has a combined cylinder- liner and not a separate liner.

Nik

Everytime I see discussion on crankshaft play I think of this video. http://www.youtube.com/watch?v=STxCKvse6Rw

Robert

I have (2) running and one I need a new case for. I run them on YS20-20 fuel, 6X3 props. I have about a 1/2 gallon through one and it idles well, runs well and has pretty good power. The other I have about (6) 2oz tanks through it. It only runs at 3/4 throttle and up. It is acting like the older one did. Just needs more fuel through it. I usually crash them before I can wear them out.

Is there any where to get the old flexible Cox 6X3 props?


Thanks.

Dru.

Dru, see this auction: 370122630831

David

BB -

Try this item: 370122630831 on theBay. A guy selling under the name of xenalook apparently has bought out a large stock of COX parts, including the SureStart inventory, from COX Models. His store has many parts, engines and accessories.

andrew

As far as anyone can tell, it's AAN. As in an aluminum piston and an aluminum cylinder which is nickle plated.

Amazing. I just love the duct tape repairs on the LazyBee. What a plane.

The whole front portion of the crank case was gone, the front bearing was just dangling unsupported up front[X(] This guy doesn`t give in to easy

Around these parts, we would say, "Looks like he got most of the good out of it."

andrew

[X(]

The owner of this Cub has to be the winner of the "Biggest Idiot Award" running the engine with the front bearing hanging out of the case.