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OS FP/LA -.15 Carb

Old 01-24-2012, 06:56 AM
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WoodCutter
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Default OS FP/LA -.15 Carb

Hello All,
I have an OS .15 FP that's about ten years old. I bought it as the "stunt" (venturi only) version and it has performed well on a couple of control lineplanes it's been on.
I had thought about using it on an R/C plane but they don't sell that model carburettor for it anymore.
If one looks at the current OS LA .15 and compares it with the FP series.15's, they look nearly the same. The Bore/stroke is identical as is the mounting width/hole spacing etc.

Tower Hobbies sells parts for the LA including a carb. I would not be suprised if the newer carb could just be bolted on to the FP's case and a remote needle valve added. The two carbs are of a different OS number but I suspect the only physical difference between them is the remote versus attached needle valve set-up.


Does anyone out there have both of those motors and can tell me if the LA's carb will fit the FP's case? I could just buy a carb and needle valve but hate to spend the money if for some reason it won't fit.

Thank you very much for any replies, I'll check back later after work.


Robert
Old 01-24-2012, 07:39 AM
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Default RE: OS FP/LA -.15 Carb

it fits....
Old 01-24-2012, 08:21 AM
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WoodCutter
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Default RE: OS FP/LA -.15 Carb

Excellent!

Thank you for taking the time to respond...

Robert
Old 01-24-2012, 08:22 AM
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Default RE: OS FP/LA -.15 Carb

I will check for you tonight but the OS 15 CVA carb is about as good as you can get. the next inline is the Magnum 15 carb. I think they both will fit but have to check tonight after work. The carb is 40 dollars though and its almost better to just buy a whole new LA 15 engine and try to sell that one if you can.

another option is to buy a used LA 10-15 FP 10-15 on here or the other place.
swap meets are also good.
Old 02-27-2013, 09:10 AM
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Default RE: OS FP/LA -.15 Carb

Need help with os 15 fp... I have acquired a used os 15 that is bleeding fuel as the rpm's increase. I pulled the carb and the o ring is not torn, but is flattenned out. Do I just need to get a new o ring, or could I have a different problem? Is there a seal on the crankshaft, do I need to pull the flywheel?
Old 02-27-2013, 12:45 PM
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Default RE: OS FP/LA -.15 Carb

These engines are not noted for their longevity......! Where is it bleeding fuel from?-around the carb spigot or from the front bearing? If the latter then accept that it is clapped-and there's nothing you can do about it. [Well you actually can-.......you could buy a replacement crankcase......if you could find one, or have a very good engine man replace the crankcase bushing-BUT either option will cost you more than the engine is worth]
If it is leaking from the carb-again you need to determine exactly where-and why. The carb could simply be loose in the crankcase-though in that case I would expect you to have trouble maintaining even running-tighten the securing screws. If it is leaking around the spigot then a replacement O-ring should solve the problem. If it is leaking around the barrel then you need to check why-scoring from dirt or debris perhaps. Carb barrels and bodies can be replaced-but if a barrel is scored then the body is likely to be scored as well. A complete replacement carb will once again run you more than the engine is probably worth.
Finally-is the needle valve assembly properly threaded into the carb body and the lock nut tightened?

First determine the source of the fuel leak, then you can make some decisions.

ChrisM
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Old 02-27-2013, 06:50 PM
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Default RE: OS FP/LA -.15 Carb

Ok, well thanks for replying. The more I think about it, the more I think it was probably from the carb area. If I don't get it fixed upon reassembly, I might just buy a new la and be done with it.
Old 02-28-2013, 03:21 PM
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Default RE: OS FP/LA -.15 Carb



I've flown a lot ofFP engines, and they all "slobber" fuel out from somewhere. And as far as longevity Ihave one I've been running since 1992I've taken it apart twice to degum it. It doesn't feel like it has much compression anymore, yet it runs; and it's black from all of the fuel that sprays out of the front bushing and carbuerator.

One of the places a lot of the fuel comes from is the venturi. I think that because the carb is an airbleed style, and not fuel meteringexcess fuel actually getsblownor drawnout of the carb and sprays all over the engine. The fp .40's and .25's that I have all do it, you can feel it (and see it) on your hands if you put your hand just behind the engine. I've oftenwondered if an extension on thecarb intake would fix that? Someday I'lltry it.

They also drool a little bit out the front of the crank case because of the plain bushing, that keeps it lubricated, it's not the same as having a bearing up front. If it runs, run it. My .15 is basically the same as the FP, but it's an OS Max, it's so old it has a strap on muffler! Still runs, although I admit it doesn't have nearly the amount of flight time my old .40fp has. And another complaint I often hear is they don't transition well, or are hard to adjust, that just hasn't been so for me. If you adjust the air bleed properly they will idle all day, and transition right up to full throttle. Most of them Idle a little rich from the factory, and will load up or flood if left to idle a lot. I'll be the first to admit though that they are not as powerful as an equal sized BB engine. They are not designed to be; the carb is smaller, the timing is different, no ball bearings. But, they are lighter than most equal sized engines, the .40fp, for instance, works nicely on a plane that calls for a .25. It weighs less than some .25 size BB. engines and will swing a 9X7 prop if you want to go fast ( have this setup on a .25 sized extra 300L...waiting for repair!) or an 11X5 on a plane under 4.5 pounds will go straight up as long as you want to climb.

can you tell I like .fp's? I've never had to replace a rusty bearing in my 20 year old .40fp, I can't say that about my YS or Saito that I've had for just about that same amount of time. I buy them up cheap at swap meets.

Austin

Old 02-28-2013, 04:23 PM
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Default RE: OS FP/LA -.15 Carb


ORIGINAL: guitarsbanjo


can you tell I like .fp's? I've never had to replace a rusty bearing in my 20 year old .40fp, I can't say that about my YS or Saito that I've had for just about that same amount of time. I buy them up cheap at swap meets.

Austin


...it's pretty difficult replacing a rusty bearing in an engine that doesn't have one......and the fp series don't!

ChrisM
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Old 02-28-2013, 04:48 PM
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Default RE: OS FP/LA -.15 Carb

I think that was his point..
Old 02-28-2013, 05:03 PM
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Default RE: OS FP/LA -.15 Carb

then it was poorly made-you're not comparing apples with apples.........

CJM
Old 02-28-2013, 08:38 PM
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Default RE: OS FP/LA -.15 Carb

You are correct, I was comparing apples to oranges, making a point about the differences. I like both, apples and oranges, by the way. I was just trying to say that for someone who is not inclined to repair an engine as I am, that the FP might in fact have greater longevity because there's less that can go wrong, ie. there are no bearings to rust. I can see how that might not have come across. I guess Ijust assumed that because I'd pointed out already that it was a plain bushing engine my point would come across, and I shouldn't assume anything. I also run fuel with 22% oil that is 50/50 castor/synthetic, that may also contribute to the longevity of my engines, and the black gum that covers them. The bearings I have replaced were when I lived on the coast in Mississippi, everything rusted down there,chips in the painton my car would rust holes in the sheet metal in short order.

Austin
Old 03-04-2013, 11:13 PM
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Default RE: OS FP/LA -.15 Carb

Ok, I put the fp back together and got it synced up with the other one. They still bleed fuel pretty bad, but I'm gonna keep 'em instead of spending another $140 on this plane. They run good but sure are messy.
Old 03-05-2013, 05:20 PM
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Default RE: OS FP/LA -.15 Carb

You may want to slip a short piece of 1/4" latex tubing over the front of the carb. to stop the fuel from spitting out.  Maybe a half inch long or so.  I t may not spit out.  If it crashes, it may pinch off before dirt comes in too, not that a crash would ever happen.
Old 03-06-2013, 11:00 AM
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Default RE: OS FP/LA -.15 Carb

pm sent to Woodcutter

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