steveg_oz

Hi,

I'm having problems with reliable running with my new OS91FX. The engine is quitting in the mid range. I notice lots of bubbles in the fuel tube from the needle to the carby. I do have a Brison Pitts muffler fitted. The tank is leak free.

what's the fix? Is it the new O-rings?

Thanks,

steve

amcross

My Feedback: (2)

Steve,
the problem is almost undoubtedly your Bisson Pitts is not creating sufficient back pressure. Please see the other thread on this engine for further details.

Dazzler

My Feedback: (6)

Steve, try putting the stock muffler back on it and try it. I was using a Bisson with terrible results, took it off and put the stock muffler on, problem solved.
Be careful, Bisson sold 2 different bisson's for this engine 1 was for a OS91FX, and the 2nd was for OS61FX-91FX, I had the 2nd one, and it doesnt work, I'll bet that's the one you have, its quite a bit smaller than the one marked OS91FX. Hope this may help!!! Daz...

steveg_oz

Thanks,

I'll try substituting the original muffler back. Any recommendation for a pitts style muffler that doesn't have this problem?

Steve

THE TAILBACKER

What really bothers me is the lack of truth here. We need answers, not excuses. Over the last couple of years the 91 FX has taken a serious beating along with the ST3250.
* You take the entire OS lineup. Now there are complaints on various OS engine sizes but most of them concern someone who does not know what they are doing. Majority of the OS line have no problems at all. If the 91fx has received consistent attention for a few years on the same problem, there is something their.
*I had two of them and returned them both. A friend has one for over a year and its fine but something is wrong somewhere.
I have several OS's 25fx 46fx, 46la, 61fx 1.08fsr Close friends have 160fx's so I'll speak for them) They are great. I would not mount a 91fx on a plane of mine if it were free.

* ST 3250 and the mid range- we don't need to go their.

djlyon

I don't see a lack of truth here. I see a guy who can't accept that everyone encluding the manufactures and manufactures reps don't quickly embrase his assessment that something is wrong and what that something is.
Your message and the "lack of truth" statement is plain harassment

THE TAILBACKER

Harassment, that is a good one. I guess the hundreds of others who complain on the "identical" problem are also harassing. We have the right to tell the mfg's they have a bad product. The only way they seem to get the drift is when sales go down. If you look through various threads recently there are several popular R/C companies that have gone under or attempting to make a reorganized comeback. There main problem is themselves and lack of listening to the market. We don't like it we go someplace else.
Here in town we had and very strong up and coming hobby store. The "manager" of the store came to the field on a weekly basis and maneged to alienate everyone around him. The owner came to a club meeting of a hundred members and asked for some business. he was totally oblivious to hie mangers mouth. Couple months later he folded.

GrnBrt

My Feedback: (5)

Tailbacker: These sub forums are not here for you to get on your soap box and slam the products being discussed. If you want to voice your feeings then either post it in the regular forums, or take it back door. I will not tolerate tha there.

Ed

Deleted

RCWI

seeveg oz where do the new o rings go that u are talkin about? Oh im sorry I have a 91 and the think sputters at high speed. i also had to put a new high speed needle valve which i had to buy one that is for a 61, they said its the same. Can you tell me if it is? Or what else do you think is the prob?

RCWI

Oh sorry to mention the high speed needle is mounted away from the carb, and at high speed it puts out small puffs of smoke as it sputters. Thank you for any help

Bax

My Feedback: (11)

This is a five-year-old thread, so if you have a current-production engine, the needle valve assembly is completely different. The old version had some difficulties with needle-valve o-rings. If you have a .91 FX that's about three years old or newer, it should have the plastic needle valve housing and different components that have solved the difficulties some people had with the engine.