OS FS-120 Surpass III Pump issues

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lennyk@gmail.com - 20 Jul 2005 04:58 GMT

My newish FS-120 surpass III with pump is developing
about 8500 rpm with 16x6 apc 15% wildcat and omega.

Somehow this does not seem right, check the tappets etc and nothing
seems wrong, engine idles and transitions fine.

What else could be wrong ?
It was purchased second hand.

Thanks,

L

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Olin K. McDaniel - 23 Jul 2005 23:42 GMT

>My newish FS-120 surpass III with pump is developing
>about 8500 rpm with 16x6 apc 15% wildcat and omega.
[quoted text clipped - 8 lines]
>
>L

Checked some of my old records on an FS-120 Surpass II, and it appears
that 8500 rpm on a 16x6 apc is about correct. That's about what I got
on a 15x8 apc, and with a 14x8 MAS it got between 9500 and 10,000.

Olin McDaniel

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RussellFletch - 03 Jul 2009 19:39 GMT

I have an FS-1200SIII purchased from new about a year ago. When I go
around to running it up for the scale biplane that I had been building
stuck a problem:-

It will start OK and I can tune up on the main needle and mixtur
control valve and it will run for 10-15 mins across the full range lik
a dream. But on the second tank it then floods and you have to reduc
the needle to about a 1/4 turn before it stalls in a cloud of unburn
fuel. The excellent OS service organisation (I am not joking) hav
replaced the pump and carb without success and we are just about to g
onto the third set.

The problem seems to come on with use and only shows after a length
period of running. What is more, it goes away if you don't use th
engine for a week or so, but then comes back to bite later on.

Anyone had this problem? If so what was the cause/fix.

Thank

--
RussellFletc

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A.T. - 06 Jul 2009 07:01 GMT

What fuel are you running? excess castor will clog system and free up once
pump etc is hot causing symptoms as you describe..
check sub sections
"Carburettors, Tuning & Performance Testing, Glow Plugs."
"Fuel facts & FAQ + Fuel Tank installations" at
Alan's Hobby Model & RC FAQ Web Links
http://homepages.ihug.co.nz/~atong

Regards
Alan T.

> I have an FS-1200SIII purchased from new about a year ago. When I got
> around to running it up for the scale biplane that I had been building I
[quoted text clipped - 15 lines]
>
> Thanks

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RussellFletch - 11 Jul 2009 14:37 GMT

Thanks, I have tried 5%/18% (nitro/castor), 10%/18% and briefl
20%/unknown. The engine is spec'ed for 10%/18%. I am using standard OS
plugs (several, including two previously unused).

I have had the engine to bits and there was quite a lot of nice clea
oil in the case, enough to pour out after removing the back plate. Th
crank-case rebreather nipples are all as quoted in the parts list an
clear and no problems with valves, compression etc.

I wondered if excess oil in the case could cause the pump to play up?

Russel

--
RussellFletc

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dobra - 31 Aug 2009 09:49 GMT

I have the same engine and i CAN ONLY GET 8100 WITH A 15 X 8

It is very annoying as i need just a bit more pull for the model it is
in.

It should go to about 9500 I think.

I am only on 10% but going to try 20% soon but it should not be like
that any way.

I think I must have a blockage some where, It is only a just run in
engine so I doubt its that. I think there is some thing a miss in the
regulator.

Signature

dobra

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Model Forum / Radio Controlled / Air Models / August 2009

OS FS-120 Surpass III Pump issues