OS 65 LA Run Problem
 

I have n OS 65 LA thatr is 8 years old. I bought it new back in 01 and broke it in per the manual. I then flew it for about 2 dozen flights with no problems at all. I did loops and rolls. It is on a trainer a/c so no heavy duty manuvers. The engine/model sat in my garage all these years unused due to lack of time to have a life beyond work. That has all changed now and Iam ready to fly again. I stripped and recovered my model. While doing that I put the engine on a test stand and ran a couple of tanks through it. I actually stored it correctly as there was no corrosion anywhere. The engine ran well. But Ihave finished my re-covering job. m Installed the engine. And now I cannot get it to run correctly. It starts fine. But when I advance the throttle it dies. Needle valveadjustments do not seem to have any effect on top end. If I try to adjust the needle valve at idle, RPM drops rapidly. HELP!!! I would love to get backin the air soon but as of now the engine is totally unreliable. Any suggestions?

Istarted out running 10%. I am running 15% now at the suggestion of my local hobby shop.

RE: OS 65 LA Run Problem
 

HI

I wonder why your LHS suggested to change the fuel....it doesn't have anything to do with your problem, it should run with 10% or less nitro without problem (if the fuel is ok..)

You have a problem with your tank, with your lines.....maybe you have connected the lines wrong by accident... maybe the clunk is now pointing forward pinching the tubing (common after a crash or hard nose landing) shake vigorously the plan and the clunk will loose.

How are you tunning the engine? if you screwed the tunning up....put the air bleed screw half way closing the hole, have the needle valve in a rich setting...go full power peak the engine, open the needle valve 3-4 clicks from top and then check the transition....you adjust with the air bleed for a good idle and transition, but not touching the needle valve!

Saludos,

Jorge

RE: OS 65 LA Run Problem
 

Hi!
Did you use Castor oil previously?
If so, have a look at the air bleed intake hole up front of the carb so it isn't clogged with old gunk oil. Standard setting is with the airbleed hole half open.
Have you changed fuel tank and fuel lines? Do it! Especially if the plane has been sitting for 8 years.

15% nitro is overkill! 5-10% nitro is just fine for the LA engines.

As for props...Use a 12x6, 13x4,13x5, 13x6 or 14x4W APC prop
Glow plug: OS 8 or Enya 3 glow plug.
Tank: 300-350cc (10-12oz) tank.

RE: OS 65 LA Run Problem
 

I will try that tonight Jorge, thanks.  FYI, I have taken my fuel system apart and put it all back together,  checking the lines for leaks, clunk position, or anything visually obvious.  No luck there.  The LHS recommended the fuel change to increase RPM.  I  was topping at 11000.  OS website shows a max RPM of 16K. 

RE: OS 65 LA Run Problem
 

No fuel will make your engine with that prop turn faster....from 5% to 15 % nitro may increase up to 400RPM when much. Forget what manuals says about power....they are not reachable with the props the enignes are intended to be.

If the man on your LHS is a modeler....he should know that... I don't trust your LHS for advise [:@]
11K RPM sounds good for a prop in the range I guess...what prop are you using? maybe your prop is on the heavy side...but for a bushed engine I think is ok.

If your needle valve became unresponsive, it can also mean that your carb has junk, make sure you can blow through the tubing into the carb...look for something that is clogging the fuel path.

Keep us posted

Jorge

RE: OS 65 LA Run Problem
 

I agree with your opinion of the LHS. No one there talks with any degree of certainty. They all sound like they atr just reading off the cover of whatever product you are looking for.Knowledge is sadly lacking. But they gave me an answer I had presupposed to be correct so I went with it. I shoulda checked here first.
I have tried 11-7, 12-7, 12-8. Afterreading the OS site I think I will go with either the 12-7 or8. Or the 13-7 or 8.Currently running the 12-8.
Yes the fuel tank and lines are all new.
I will be getting home around 7pm central usa time. so I will look at the carb then and try this all over again. I will keep you all posted later this evening.

Fuel tank is 12 oz. I do not remember which plug the LHS`sold me. I'll check that when Iget home. Thanks fellas.

RE: OS 65 LA Run Problem
 

Prop choice depends on how it performs the plane in the air...

a 12x7 will give you more rpms.

I'm not sure since I don't have that engine...But I think you can forget the 13x7-8 props....

RE: OS 65 LA Run Problem
 

The LA .65 is a real torquer so, since its on a trainer the 13x7 would work quite well. The 13x8 would be pushing it.

RE: OS 65 LA Run Problem
 

That's 16k rpm on a dynomometer where the operator can reduce the load on the engine to allow it to rev up that high. That is not a practical rpm that you should be able to attain on a propeller. Your engine is running right where it should with the prop you have mentioned. The 15% nitro fuel certainly won't hurt the engine, but it is a waste of money for an OS .65LA. What 15% nitro fuel will do is broaden your needle valve settings (makes the needles easier to adjust).

I'd take the carb apart and look for particles or threads of plastic fuel tank/fuel line that have gotten loose in the system and plugged your carb's jet.

What kind of clunk do you have in the fuel tank? Is it a sintered bronze clunk? Sometimes this type of clunk can plug up after years of storage. Lots of folks used to remove the clunk and put it in the flame of a propane torch for a little while in order to clean it up/out.

Keep plugging away, you'll find the problem.


Ed Cregger

RE: OS 65 LA Run Problem
 

what i have found with my os .40 fp (airbleed engine) is if you set the highspeed to rich (even a few clicks off) it wont transition very well if at all (engine dies)
so what i do is peak the rpm's then back off 4 clicks, and fly the plane for a few min, land, kill the engine and spit on the cylinder head, if the water instantly boils off i richen it a few clicks more. repeat until you find the sweet spot where the engine doesnt overheat and still transitions well. im sure theirs a better way to to that with a airbleed engine but it works for me.

RE: OS 65 LA Run Problem
 

Your tunning method sounds wrong to me.

If the engine overheats, it will tell you dropping the power, and behaving bad. There are some engines that may run hot and aren't overheated, and boil water instantly.... Listening to the engine, it will tell you if it is doing good or not!! temperature is affected by many factors and in plane engine is in general meaningless...

If your engines doesn't transitions well in an air bleed carb, that's why you have an air bleed screw...you find the max rpms with the high speed needle, then a couple of clicks back to drop rpms about 300rpms to compensate for a lean run in the air.... on idle, if it tries to die when you throttle up, then screw in the air bleed because it is lean, if it sputters and throw much smoke, then you have to unscrew the air bleed screw... you'll find a compromise there.

The mid range should not be set adjusting the high speed needle, the high speed needle is for setting the peak rpms!!


Saludos,

Jorge

RE: OS 65 LA Run Problem
 

Hi!
The best way to set any engine is by listening to it!! Setting by ear!!