foaming tank???

[scooby61]

my 700 makes the tank foam up considerably i've read one other post but the os bubbleless clunk didn't really help i think this is making my tuning very difficult. my ys 91sr seems to lean out and burble whenever i bank the heli over. i've checked all my bearing blocks and retightened everthing i can find for vibration in the heli all seems smooth but still a lot of foaming in the tank only when in the air while idleing it settles down. any help appreciated in advance.

[cbdane]

Main/tail blade balance? Flybar centering? Those are the first places that I would look.

bd

[helis101]

I have the same issue with the tank foaming up buddy of mine thinks its because the tank fits so tite in the frame getting vibes causing the foaming. Tracking and everything is right on, and i was flying today trying to tune my ys 91 sr, i was also haveing a problem with it running lean couldnt figure it out.

The fuel i was useing was CY 30% ,Mp 5 pipe then i remembered some where someone saying they were haveing problems useing CY 30. That cool power ran better with this engine no detonateing, So i figured why not try another fuel bingo that was the problem got it tuned runs great now but still seeing some foam/turbulance in the tank. By the way fuel i used that worked for me was Magnum 30%

[Mercuriell]

Mine doesn't foam appreciably using a fuel magnet clunk - in another thread it was reported the OS bubbleless clunk foamed it up a bit more

[scooby61]

thanks it sucks if cy 30 won't work well i've got 3 cases of it, but i'll check all my balancing items again.

[jgeorgic]

I have the same problem with mine getting churned up.I am going to take a look at the opening in the fuel tank pressure inlet as Bob mentioned that there might be some flash from the molding process.Not sure if that will help or not but it's worth having a look at.

OS91SZH-Hatori SB18FH

I started with the OS bubbleless and then switched back to the stock one.Going to give the OMI fuel magnet a try.

[4cyclic]

excessive clutch runout will do that. Just double-check if your runout is no more than .0005 (half one-thousandth of an inch) is best. Max is 1.5 thousandth. Mine was 2 thousand of the bat, and some fiddling is down to 1/2. If that doesn't cure it, then check tail blade balance. Balance the whole tail assembly, not just the blades. Hope it helps

[scooby61]

tried the cool power no help. clarify what you mean by clutch runout do you mean the clutch is not consistantly round or the clutchbell? i guess i will pull the thing down and check everything this is driving me nuts.

[4cyclic]

clutch runout is the clutch outside perimeter at two points where the 4mm screws are located. Only the sections that don't pull out under rotation are checked. You start with the clutch hub inside diameter and work after to the clutch itself. A dial indicator is really inexpensive and a good investment.

[Mercuriell]

I'm not getting ANY foaming using Coolpower Red oil in a 20:20:60 mix and an OMI fuel magnet

tried the cool power no help. clarify what you mean by clutch runout do you mean the clutch is not consistantly round or the clutchbell? i guess i will pull the thing down and check everything this is driving me nuts.

If you wanna check out the painful process of dialling in the fan you can watch it on my Stratus build video (http://video.helifreak.com/?subpath=mercuriell&filename=Stratusdialhub.wmv)

[scooby61]

found part of the problem tail boom in too tight had the tourque shaft bowed and cavitating in the boom. tank still foams but now only in idle 2 after flying around a bit. so i got the fuel magnet and a new tourque shaft the original seems to be still alittle warped. hopefully this will fix it.

[4cyclic]

keep us posted. The TT bowing , that is something to check.

I'm also getting a bit of foam on full tank and some fuel jostling at mid to low fuel level.
with the fuel magnet, nothing shows through on engine needles, but it still bothers me .

[jgeorgic]

I cleaned out the inlet mine into the tank to remove any flash from the hole and switched over to a OMI fuel magnet,

The foaming is not as severe but still there.Does not seem to affect performance.

[bmlasater]

fwiw..

Almost certainly something out of balance in the engine assy, or engine tuning...Too lean in I/U almost guarantees foaming...

John.

[scooby61]

alright, putin fuel magnet, replumbed all lines, bored out pressure inlet on tank, richened mid needle, reduced headspeed to 1900 in idle 2, still foams slightly but now my engine runs right. and i can finally flog this some.

[scooby61]

Finally got this thing running right, and i love it still a little foam in the tank not enough to give me concern. this thing flys awsome on low rates i'm not even sure i need highs. and the tourque and power sooo smooth and it just flys effortlessly through any maneuver my skills are capable of. i've got a new favourite chopper hope my 600 doesn't get too jealous.