coloradoz

My Feedback: (38)

OK, got the 10cc - but I'm having some issues with it:

History: Had the 10cc, and it has been sitting for quite a while - took it out recently on my test-bed plane. Running Cool-Power 10%. When it runs at full throttle, is sounds good, idles well, but .....

1. there is s greyish residue mixed with the expected greenish stuff from the castor - what is going on here?
2. transition is not crisp. Between idle and full throttle it is sluggish - what is going on here?

Thx.
...AJS

Spaceclam

the grayish residue sounds like metal flakes mixed with engine grease or something like that. if you have a metal engine mount that has oil between it and the motor, that could be your source of it. also, about your throttle transition. sounds like an improperly set low end jet to me. sounds rich if it is sluggish. locate your low end needle. it should be on the carburator barrel on the opposite side of your throttle arm. that little jet is responsible for the transition and idle of your engine. it will idle fine with that at a wide range of settings, but if it is too righ the engine will hesitate and blubber. if it is lean it will drop rpm and may even die. try leaning it out about an 8th turn and see what happens. keep leaning it out until there is no hesitation.

coloradoz

My Feedback: (38)

Thanks - I do have a metal mount, so I hope that takes care of that one - on the carb - I did clean it up, and probably buggered up the settings. I think the low speed is on the same side as the throttle arm (on this carb) and the high speed is on the opposite side (fuel inlet) - I'll try leaning out the low speed setting to see if it clears up.

Spaceclam

well, the low speed is usually on the carburator barrel. the only exception i know is ys.

bdtsr

My Feedback: (5)

The low end is on the throttle arm side, high end is on the fuel inlet side. The crossover point is adjustable be moving the needle ass'y in or out. The brass nut on the inlet side is the lock nut that holds everything in place.

coloradoz

My Feedback: (38)

OK, roger on which needle is which. But now I'm confused about the crossover point. I didn't think I could adjust that - what are the groundrules about where to start and which direction to make the adjustments?

...AJS

Spaceclam

ok. first of all, the high speed needle only controls about the top 80-100% of your throttle. your low end adjustment actually works the same way as your needle. it is a little needle. the fuel comes squirting out of a little jet, and as the carburator barrel screws outwards for full throttle, the needle is pulled out with it. if it is too lean, it will pull out of the jet late it won't let enough fuel out until it reaches that 80-100% of your throttle. it will starve and either drop in rpm significantly or even die. if it is rich, it will pull out too early and flood it with fuel. if it is way way too rich, it will blubber and die. but the way it is set right now, it sounds like an 8th turn rich or so. your engine will hesitate, but not drop rpm. there is a chance that it will also blow some smoke. it is not harmful, but can be potentially if you full throttle it vertical and it floods. look in your carburator barrel. you see two little things sticking out. the one that is on the side where the fuel line plugs into the carburator is your jet. the other thing on the opposite side is your low speed adjustment. by richening or leaning it, you adjust the crossover point. richer is sooner, leaner is later. that is what causes your engine to be rich or lean. look at the way the threads on it. i can't tell you which way to turn it because it varies from engine to engine. i have no personal experiance with webra, so i can't tell you which way it turns, but that transition problem is associated with the low end on most carburated engines, the exceptions being some of the ys ones, and some pumped engines. you will have to see which way to turn it by the threads. leaning it out means you bring it in. try an 8th of a turn leaner. if it gets better, but not perfect, go to 16th turns and fine adjust it. if at any point it drops rpm though, it is too lean and bring it back a bit. don't worry though. it is a lean transition, but there is enough lube in the engine that it won't overheat. it isn't a danger unless you run it in transitions all day long. let me know what happens.

MrMotor

coloradoz
After sitting all those years did you put in a new idle bar plug in that cross flow engine. If you don't have an idle bar plug in there that could cause some of your transition problems too.

Spaceclam

he never said it was that old... did he?

MrMotor

The Webra Black Head is an older engine that has conventional porting. It was replaced by the Webra Silverline 10CC which is also discontinued.

coloradoz

My Feedback: (38)

Yep, I put in a new plug on this beast. In my reading on this topic, I was also wondering if the location of the needle valve assembly(on the high speed side) within the port. It looks like this is adjustable - but I have no guidelines in order to locate the spray bar within the inlet port.

Spaceclam

this is how it is set up on my engine. on some engines it is on the other side. on mine, it is set up on the throtle arm side. however, i do have one set up on the other side. the low speed needle is what you have to adjust.

coloradoz

My Feedback: (38)

Ok, that helps - how big is the gap between the needle and jet? And is the gap positioned exactly in the middle of the port?

Spaceclam

there is no proper gap. it will vary from engine model to engine model, the way it was broken in, the % of nitro and oil in your fuel, etc. you have to find it by trial and error. like i said, try leaning it out first because it sounds like it's rich. if it gets worse and drops rpm instead of just hesitating, you went the wrong way. turn it back, try it once to make sure it wasn't something else, and adjust the other way. if it just becomes different but not any better, there is a good chance that you are adjusting too much. adjust just a little at a time. to find the general area, 8th turns are great. when you get near there, go by 16ths.

coloradoz

My Feedback: (38)

Sounds like I had better take extra batteries to the field, plenty of tools and patience.

Spaceclam

uhh, all it requires is a small screwdriver. a small flat-head for most engines. the low end needle is like a screw. first, warm your engine up. let it run for about a minute. before you shut it off, idle it down and wait a couple seconds. then, full throttle it quickly. if it hesitates, try it one more time. if it still hesitates, turn the screw (on most engines) clockwise an 8th turn to lean it out. start it up again and make sure it is plenty warmed up. try it again. if it is better, but not quite perfect, give it more. if it is really close, go in 16ths. if that hesitation is it running leaner, (which i really doubt) than it will only get worse. put it back to center, (make sure to do all these adjustments with the engine OFF. and try it once more to make sure that it is not something else that made it worse. if it gets better, keep turning it the other way until it is perfect. you won't need extra batteries. this should only take about 5 mins of actuall opperation time.