nauticom

Maybe some of you can give me some in site and guidance for the future. Here we go.
Have had this OS Surpass 4c 2 years.
Last year it ran great in a 4*60. This spring, one flight, started to surge. stoped flying, went home looked it over, back to field, would not start-no fuel flow, back to OS factory: Quote: "Your carb was full of debris and we replaced the pump and regulator". Back in plane--everything fine for maybe 25 flights--took 8 weeks off, no flying. Resumed at field-be advised I run my engines quite rich, about 500 rpm off top( in this case 8800rpm and a 14x6, Wildcat 15/18 all sync fuel).
Set up engine, lots of smoke, take off roll-no power, just got off the ground with a 71/2 # plane. Flight speed was gone, just enough speed to keep it up. Brought it back asap.
Engine had leaned out big time-toasted, plus many black specks on top of plane. My feeling is the pump/regulator failed and leaned out the engine. I will be sending back to OS. Do you think I sould ask for a replacement engine W/O pump or stay with the pumped engine fixed up by OS?
Has anyone else out there been having these kinds of issues with what is really a new engine, 2 pump failures in such a short span.
It seems that these pumps do not like to be setting around for a few months idle.
I'm getting VERY gun shy about pumps--I'm about to lunch my Saito 170R radial in my GSP Corsair and have a Kline pump. Should I be using that thing--are they prone to this kind of failure mode?
Do I really need a pump for scale type flying?
Thanks much in advance-you guys are top notch.
BobM
nauticom

StarskiPZ

Just read your post...

hope you have made progress to date??

I was wondering what the type of oil was in the wildcat fuel, and or where your fuel filter/s are located

regards,

starski

w8ye

My Feedback: (16)

First of all, the Cline is a demand regulator and there's no pump in it. On a 2 cycle engine, they tap crankcase pressure via a check valve that pressurizes the tank to force fuel to the regulator. With your four cycle Saito, you will need to run a Perry oscillating type pump (Which has no regualtor!) for fuel pressure.

Both of these devices use diaphragms that are prone to gumming up. So you may just have the same trouble with them that you have with your pumped OS engine.

Good luck,

Jim

nauticom

Ok here is an update with the 4C engine repair by the O>S tech at Tower Hobby: You toasted your engine because there was debris in the carb. and that is what caused your engine to lean out and over heat and be ruined.
I could not see any stuff in there before I sent it back.
So they offered to fix the engine for around $100 or I can trade it in for a new Surpass II for $180. I chose the latter. So here I am, after 2 years of problems( I did not bore anyone with the fact that I had first purchased a FX 91 and after 3 trips back to Tower for the !QUOT!bubbles!QUOT! in the fuel line problem), upgraded to the Surpass for an additional $60. So now I have a new SurpassII and for a total investment of about $250 + 60 + 180 + shipping a few times comes out around $500. Not a good feeling for what I still believe to be basic design/operational flaws with the OS Surpass 91 pumped engine.
Closing, this will be/is the last OS engine to enter my hanger.

StarskiPZ

To answer your questions. On fuel the Wildcat fuel was 15/18 premium extra. The oil is all synthetic. I filter the fuel from my fuel jug while fueling. I have not been using an in-line fuel filter in the plane. I have never had a problem before doing this. I guess I've paid the price and will now do so on all my planes.

w8ye
Thanks for your inputs. My real main question is this: I have a good fuel tank location on the Corsair, tank is about 1 inch from the firewall, and in line with carb. Fuel line is about 4-5 inches. Why would I need any fuel system booster, such as the Kline regulator, or the Perry pump for that kind of installation. Is it simply that these Saito radials need it/them?

sledman

My Feedback: (2)

I have an OS .91 four stroke on my Goldberg Extra, and it runs great, at about 9600 RPM with a 15 x 6 K-series M.A. prop. Never needed a pump. I haven't had the engine very long, and it is my first four stroke. I have to say, that I really prefer 2-strokes, but this was a fairly new engine, and it was on the plane when I got it from a very reputable member of our club, otherwise I would not even have considered it. What would a pump do for my situation? It seems to work fine the way it is, and I may be trading it anyway, and replace it with a 1.20 2-stroke.