Wow. That escalated quickly.....ebay haul.

I know the feeling. If you find yourself on the verge of
saying "this is the last one", don't do it! Only going to
cause you more trouble down the road.
Bob

Nice haul, was that one listing? Photos and links are cool!! I can only keep stuff from the wife so long, I don't have a poker face.
She does a lot of female stuff (hair, nails, massages, ect, ect), she can spend 150$ at a dollar store. I haven't even figured that one out yet!
So don't feel to bad, welcome to the club!

Hahahah This is a good forum! Great replies! They were all separate listings but I got them all for good prices. Crankbndr, how in the heck do they spend so much at the dollar store? Mine does that too! I was able to get five engines for that price lol. Marleysky, I just work very late every night so number one I can recoup expenses and she's asleep when I get home hahaha.

Yeah its addicting buying these little engines and parts...just bought my first pee wee today and spent a $112 at Cox store on various parts...but I love these little guys!

Canso.

Canso07, They are a blast! I can't wait to get off work early enough one day to fire up a few that came in the mail today. However one of them may need a new P/C because though it says it's new it has very little compression. Maybe caster will fill the gaps. Doubt it but we'll see.

Yes it's always hard to determine what your buying unless it's new in the package. Sounds like new p/c, it is hard to bring the compression back up once lost. What kind of treasures did you buy FlyingCox?

Canso.

This black widow II supposedly was nip. It came in Cox International packaging but was being sold by and individual as new. The piston doesn't look like it's been run but I can't see cox Intl sending out something like this. Obviously this is a newly put together engine but something is a miss. That's ok though. All my other engines are in great shape. I can handle one dud.

This black widow II supposedly was nip. It came in Cox International packaging but was being sold by and individual as new. The piston doesn't look like it's been run but I can't see cox Intl sending out something like this. Obviously this is a newly put together engine but something is a miss. That's ok though. All my other engines are in great shape. I can handle one dud.

Typically when compression is low as you mention, it's not always a bad piston or cylinder. Many times these are diagnosed as such but all it is is a bad seal at the glow head. Ditch the head gaskets and install new ones. In addition, flatten the glow head on piece of 400 sandpaper on a piece of glass. New gaskets keep the head from loosening and provides a better seal. I've had many Cox engines with little to no compression and these were my best runners. If the engine starts easily I wouldn't be concerned with the fact the engine doesn't have a hard snap to it.

You need to find sellers that will bundle model-engines with vacuum-cleaners... No.. "Cosmetics"!!! That will solve your whole problem.

Excellent advice ken

I fiddled around with the head a little last night to see if I could get it to seal. I havn't as of yet tried a soap test on it. I may get around to that tonight to rule it out as the cause. If there's no leak I'll try starting it to see if it's just one of those oddities that still runs well.

Well I finally got around to seeing if I could get the BW started last night. There was a pretty serious leak from the head gasket. The gasket itself look to be in great condition so I cleaned the cylinder surface to make sure nothing was holding a gap in the gasket. I went ahead and used some sand paper and a machined flat surface to make sure the head was true. There are no more bubbles coming from the head and the compression has improved. She fires very well and the snap starter is really unessasary at this point. However, I can only keep her running for around ten seconds and thats only after topping off the tank. If I can get home early enough today I'll pull the tank apart and check the pickup tube, reed, and venturi gasket.

A key tool needed is a large syringe. With the tank in your hand ( This only works with the reed that uses the clip to retain it) place a small piece of tubing on the end of the venturi of the tank. Push to allow the air to pass through the reed and then withdraw it, you shouldn't be able to pull out the plunger AT ALL. If the reed is passing air when you withdraw take it apart and flip it over and try again. If you have a true stunt tanked version, push a small piece of wire through the vent pipes to insure they're not clogged. Make certain that a piece of the needle isn't broken off in the needle seat. Remove the needle and place a small wire through the needle valve seat and you should visually see the wire through the venturi opening in the screened window hole.

             Reassemble engine and with the needle valve screwed all the way in ( Don't overtighten ) place the syringe on the vent pipe and proceed to introduce air into the tank. You obviously have to use a plug or your finger to cover the opposing vent. If you here air, it's generally coming out of the screened hole in the backplate. This is a indication that the o-ring is not sealing properly. However you can also have a leak coming from the tank to backplate joint which dental floss in the v-groove of the tank can seal that but it's a pain in the rear to keep it in there and oil in the groove can assist. The screws can also leak at the backplate which depending on the severity of the leaks can cause poor engine running during flight which also can result in a loss of fuel shortening the flight. These can be sealed using a piece of cotton swab pulled from the Q-tip wrap it around the screw just under the head as if your using Teflon tape. Wind it onto the screw counterclockwise so that it tightens onto the shaft of the screw when tightening. Leaking screws can be detected by using soapy water on the heads and using the syringe to fill the tank with air.

        You can also develop a leak between your crankcase and tank joint even using a gasket. Place the soapy solution on that area when pressure checking and if it's problematic, sand the back of the case on a flat piece of glass just like the fix for the glow head. You may even find leaks coming from the threads of the needle valve when pressurizing. Loose the spring and use a #4 washer on the needle. Next place a piece of medium fuel tubing approx 5/16" long onto the needle cut squarely both ends inserted up to the washer. The washer seals the top of the tubing keeping any air from entering through the threads. The size of the tubing may have to be adjusted either lengthened or shortened depending on how much you can turn it without distorting it. Good luck.

Thanks for all the help!! I think I'll mess with the TD's untill I have more time to fight with this one. It's pretty sad that a "new" engine with no visible run time needs this much tlc to run at all. They should sell these as "unfinished".

I hope my post wasn't accepted to deter you from using the engine as it certainly wasn't my intent. I was simply pointing out critical areas that can plague a reed valve engine from operating reliably. It took me a long time over the years to understand these little engines and understanding the problem spots and looking for them easily put a lot of life and enjoyment back into these engines for me. Seeing that you stated the engine ran for only a few seconds, I was offering my experience with problematic engine runs. Yes, a reed valve engine can certainly be finicky at times working one day and taking a dump the next, but they're certainly great enjoyment. Ken

Not at all and I very much appreciate your help. I'm just lucky if I get an hour in a week to mess with these engines. When I do have that time I need something that is flight ready.

Ken gives good advise. SOP on any engine I clean is to run a fine fire through each orifice on any engine, spray bars in particular. Lot's of gunk can collect in those areas.

MECOA has gaskets.

http://www.ebay.com/itm/281232367208?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Glad to see that your having so much fun with these little engines.

Bob

I'm having a blast with them for sure. This one is really pulling my chain though. The absolute only thing I have yet to try is sanding the back of the crankcase flush. It fires up wet leans out and dies. I suspect a leak at the venturi but I've already made another gasket for it.

Oddly enough I've also noticed that the needle valve will not completely shut off the fuel so as I fuel up the tank the engine floods. Also I managed to sand the back of the crankcase flat too. It did have some high spots. Maybe I can try it out again tomorrow.

One thing to test would be the spraybar / needle seal. Remove the backplate, attach a piece of fuel tubing to the fuel nipple, completely close the needle valve and suck air. If air passes through then that is the issue.

Some time ago we had spraybars and needles manufactured and, at some point, realized that some of the parts were not to specs. By that time we had sold backplates, needle valves and engines with those components. In the meantime those two parts get checked with OEM needles for the spraybar, OEM backplates for the needles and every backplate assembly gets tested before shipment.

We would not normally warrant 3rd. party sales but, because the engine obviously originated from us and we are aware of the issue, offer to include a new backplate & needle with your next order. Please make sure to let us know about this when ordering and our apologies for the inconvenience that you have experience with one of our products.

That must be the issue as I can blow enough air through the needle/spraybar while closed to hear the air rushing through. I definitely appreciate the offer to replace the parts!