colled

I'm having a major headache trying to set up my West .50 T1 in my Hype 3d. The problem is the mid range is just random in what power it decides to put out and it's sounds sick, and as most 3d is carried out around the mid range, this needs to be spot on and predictable. The top end is fine as is the idle and the engine transitions from low to high fine without a hicup so I think it's setup ok. It's just when I try to fly around on medium throttle that it doesn't like it. I've tried everything, different plugs, changing tank foam padding, fuel, even a new carb. I'm running on West's prop plugs and 10% Pro synth fuel as recommended. Anyway last night I decided to pressure test the setup to see if any air bubbles are getting in somewhere and I found that all the fuel lines, tank and carb are air tight, but the front bearing of the engine is leaking air. Presumably this could affect the running of the engine as air can get into the crankcase without gping via the carb, and wondered whether this could be the cause of my problems ???

Any ideas ?

The Ghost

Colled,
Don't know the engine, However, does the engine throw out fuel at the nose of the engine while running. Are you running a tuned pipe or standard muffler. I have a Rossi 61 piped that is very wet on the nose while running. How much air pressure were you using to test. Sounds like it is loading up on the midrange, With a two needle carb, try leaning out the idle needle 1/8 turn. The leakage could cause problems if ti is sever enough. Good luck.

Cheers,

Remembe, Always look after the ORGANIC part of the model.

Ed Smith

Fuel coming out of the front bearing is a desirable condition. It shows that the bearing is getting lubrication. When the engine is running there is enough pressure building in the crankcase to push some fuel between the crankcase and the shaft through the front bearing. At the same time air cannot enter this way. A front bearing condition cannot affect the needle setting. If the bearing has failed it will affect the way the engine sounds or runs.

It sounds more as if your tank/engine/carburetor setup is not suitable for your use.

Ed S

colled

It doesn't seem to be a bad leak, and I haven't noticed it throwing fuel out the front so maybe it's within tolerance limits. I have noticed that the engine will run on for about 20 seconds when the carb is closed though, which I have seen other threads talking about in relation to air leaks in the front bearing and changing them.

It's running on a Weston Genesis throttle pipe, which is recommended for the engine and comes with it, but the symptoms are similar to an engine running on a tuned pipe. i.e. variable non linear mid-range followed by sudden power.

It doesn't splutter when transistioning from low to high like a rich mid range setup.

The Ghost

Colled,
Could be pipe setup, they will load up mid range if the pipe is tuned for flat out running. You could try adj pipe length 1/4" at a time. Or the pipe may be tuned for hispeed running. Length of cones in pipe determine the RPM that the pipe comes on tune. Shorter cones have a narrow RPM band, longer cones have a larger RPM band. Diameter of pipe also has effects on RPM band width. Length of pipe from largest dia of cone to glow plug is used for max RPM.Far to much to go into to deep here. Do some serches on tuned pipes and you will find heaps.

Cheers,

Remember, Always look after thr ORGANIC part of the model.

CoosBayLumber

My Feedback: (1)

In past if the engine runs for several seconds after carburetor is closed off, it means you have excess soup in crankcase. The excess soup is actually unburnt fuel/lubricate mix. You are running too rich, or something is not permitting the engine to consume all of the fuel.

As responders have mentioned it points to for some reason you are running too rich. Perhaps the needle valves are imperfect, and way too far out. Try going the opposite routine. Set needle valves completely closed and attempt to start, then keep opening them until it goes. And then check the needle. See if or not the adjustments come back to where it normally is set. Your engine may be reacting to imperfection at a way out condition to give an artificial leaner mixture.

Wm.

The Ghost

colled,
One other thing that you have to think about is that most tuned pipes are designed to give the motor more top end, and the pay off is that you loose low to midrange power.

Cheers.

Remember, Always look after the ORGANIC part of the model.

rmh

Ghost - that's really not how the pipe has to work.
Depending on the pipe design and length- the entire power band can be altered for the better.
The job it is supposed to do, is to PULL in a larger charge for the next big bang.
You don't even need high timing to use a pipe - 150 degree exhaust setups can see a big improvement IF you have the intake timing correct.
May times tho - the pipe/timing is set to start working ONLY at very high rpms - In these cases the entire power band can become a worse than open exhaust setup and even cause the engine to flood out and kill.
Those are the setups you probably are familiar with.
we use tuned pipes on engines turning only 7000 rpm and they pull harder thru the entire power band.

bigchap

i have seen a post like this before,i think weston recognise the problem and have a fix for it,give them a call.