rpat

Hi guys,
I got a problem with my engine it's a 20 year old OS 61 fsr abc. The engine has about 1/2 gallon of fuel run through it. To make a long story short I had it in a plane about 20 years ago and it wasen't enough power for the airframe so I put it back in it's box and put it in my cupboard for a long time. Well I bought a ucando and figured that this engine would be ideal for this model.
Well I can't get the engine to run for any amount of time. I took the carb off and cleaned the carb. out. The carb is a model 7M. It has a mid range and a high speed needle for adjustment. I have tried every thing that I know how to do to this carb. to get it to run. I am ready to give up on this carb and I would like to know what carbs are OS using these days on thier 61 engines. I can not use the remote needle unit because of the cowl. If you could put me on to one of their more newer carb's I might give this engine a new start on life. I need to know the carb number stamped on the carb.
Thanks
Rich

stang

My Feedback: (1)

I wouldn't give up on that carb so soon. I have them and they have been great. You haven't mentioned if you have tried a different glow plug or fuel. Maybe those are the problem?

Johnkpap

I would do the following:-

Set the carb back to factory settings

Buy some fresh fuel 20% castor 5% nitro

Buy a new os #8 or enya 3 plug.

If this Does not work then, try replacing the needle assy they can get a slight bend if they are dropped ect.

Johnkpap

safeTwire

My Feedback: (2)

Possibility of the carb mount O ring and the small gasket on the needle valve assembly base are failing.

If you do replace the O ring...before you tighten the 2 screws holding the carb, apply and hold downward pressure on the carb with your thumb, then tighten the screws.

rpat

OK guys I have tried all of the above mentioned. Now what I did do was tear down the carb to clean out the passage ways when I first took it out of the box. I am not sure if I put it back together the right way. I can not find an exploded view of the carb so I was just guessing as to the way that it went back together. That is why I would like to try another carb on it. If any one out there has a fairley new OS 61, I would like to know what is the model number on your carb.

JohnBuckner

My Feedback: (1)

http://www3.towerhobbies.com/cgi-bin...&I=LXCA63&P=RF


Here is the carb for the presently current OS 61FX. As to would it work or the the venturi and boss sizes being the same I would not want to speculate.

John

rpat

Thanks John,
That one that you showed me is the remote needle one. I need to find one that is the standard design, and I know what you are saying about the neck size being the same.
Rich

safeTwire

My Feedback: (2)

How about an email to OS with the model/year of the engine and ID# of the carb, asking for the current carb replacement?

Another line of thought...As the engine runs, there must be plenty of residual "crud" that is loosening up a tiny piece at a time. Have you tried: Fresh fuel, New Plug, Bigger Prop, and run the engine on a test bench for several tanks? Just trying to figure all the angles and be of some help

landeck

My Feedback: (1)

The OS 61 SF ABC carb is model 7L. The 61 SF followed the FSR and came before the current 61 FX. Currently I have a OS 61 FSR ABC mounted in a Sig Kadet Senior. It has been going great since 1982. I also have SF's currently mounted in a GP Super Sportser 60 and in a BH Trojan T28. And last I have a OS 61 FX mounted in a H9 Pulse XT 60. The GP Super Sportser with its SF has been flying since 1990. All of the engines run great and have never given me a bit of a problem.

BTW, I checked the instructions for the FSR carb (7M) but they do not contain an exploded view.

Bruce

rpat

Safteywire: I am going to give OS a call and see if they can help me out on this one.I tore down the idle and mid range and did not see any thing out of wack like crud or dirt, but I am not sure that I replaced every thing the way it was originally. I ended up with a little sleve after I put it back together , but I don't remember taking it out when I tore it down. I did not take the idle barrell out so it could not be from inside the carb.

landeck:
Thanks for the model number-7L- this might be the answer to my problem. I can let it idle all day long on the bench and it will just purr., but when I take it up and do a couple of manuevers with it and then bring it back to less than 1/2 throttle it quits on me, and then its a dead stick landing. So far I have been able to get it back in one piece but how many times can I go to the well before I bite the big one.

rpat

Land;
I went to the os web site and they do not list a 7L carb. They list my 7M but not a 7L. Are you sure that this is the carb number on yourb engine?

landeck

My Feedback: (1)

Yes, I am sure. It is OS part number 27781000. 7L is stamped on the back of the carb. The part number came from the list of parts for the 61 SF.

Bruce

rpat

OK I will try the 277 number

Gray Beard

My Feedback: (-1)

Why not go into the glow engine forum and get into the factory support and just ask Bill Baxter?? He answers back very quickly.

JohnBuckner

My Feedback: (1)

There is sure a lot of things wrong with this picture. First and formost whats with the big drive to replace the carb. That second statement above is a giveaway that their may be nothing wrong with that engine that is perhaps before pieces got left out of it possibly. It sure sounds like a tank and or plumbing problem.

Is the clunk pinched forward from a hard landing?

Does the clunk reach the rear face of the tank?

Have you observed good practices in the vital tank center to carb spraybar height relationship?

Is the engine mounted inverted and if so agine have you observed good practices in the vital tank center to carb spraybar height relationship? These good practices do not change whether or not the glow plug is pointing up or down.

Is there a leak in the external fuel hose both the feed line and the pressure line?

Is there a leak in the fuel hose from the clunk to the through tube in the tanks bung plug. This one is a good one and responsible for a lot of returned engines with nothing wrong.

Is there a leak in the bung plug itself? Which bleeds off any muffler pressure.

Is there a blockage of the muffler pressure nipple on the muffler?

Are you using any of the in cowl fueling ports (valves)? This is my personal favorite for being most responsible for returns of good engines.

John

aerowoof

the fsr series used the 7d,7m,7h carbs.the 7L was used by the sf series,there may have been an overlap where the 7L was used on some late fsr's

safeTwire

My Feedback: (2)

rpat, The debris I was referring to is the gum/varnish/etc. that clings to the bearings and other internal engine parts. This stuff can loosen up, circulate and "rain on the engines parade"!

A good re-run-in should clear it out.

MetallicaJunkie

The FSR come with an advanced 3 needle carb, i wish they still made them

rpat

John,
I just replied to you but the damn quick reply timed out on me. See if I ever use that thing again. Any way out of all of your suggestions I will check to see if the clunk is ok and make sure that the pressure tap is open. I don't use those crappy dubro fillers, a trully bad product. I have tried both idle and non idle bar plugs to no avail.There is no bubbles in the fuel line nor is there any thing leaking. The thing drips fuel after I fill the tank before I get the thing started. It is in a ucando and the engine is inverted. the tank is lined up with carb.
Rich

rpat

I don't want to ignore you other fellas that have tried to help me out here

Aerowolf I did find a schematic for the carb by looking at some of the other 7 series carbs. I found a blow up of the idle parts and I do have it together the right way

SafeTwire the engine only had about 20 minutes run time on it about 20 years ago. When it runs it is a very strong engine. I am running a 7 1/2 X 11 on it.

bonehead2434

My Feedback: (179)

come on guys i know if you had a engine that has been run a bunch of years ago and now you just start to run it again without changing bearings ,,,ive got 15 of these engines and if you ran any of them once the bearings are rusted up very badly regardless if you put oil inside ,,,os bearings are not so good when they are new ,,if you spend 8.00 on some new ones you will think that the engine was the best running engine youve ever owned ,,trust me take a minute and remove the backplate and check if there is any sign of rust (and i know there is ive got new never started engines that does ) change them and put your carb settings back to original ,,,,also if you dont like the os carb thunder tiger pro has a carb that works wonderful mabe a little more forgiving than a os stock carb ,,,but only after the main problem is fixed call me i can help you and even fix it if you want me too ,,,502-445-8147 i will have it screaming in a hour ,,,,,,,,,,,,jerry

safeTwire

My Feedback: (2)

Maybe borrow or rig up a stand placing the plane inverted so the engine is upright, then put some run time on it?

although...

bonehead makes a valid point about bearings that have been sitting for a while. Take a peek under the backplate, you might be shocked at what you see.

Live Wire

For kicks What muffler are you using.
Larry K

Is your engine over heating. How much air is traveling over the engine . How about a pic of the front of your plane.

rpat

OK guys it's not the bearings...the thing runs like it is new because it is new. I put risoline in all of my engines before I store them for any ammount of time. I put my heat guage on it and the hottest I read was 190 degrees and most of the time it was about 170. I am running the original Muffler on it. I think that John's comments are the closest. I have a sneaky feeling that the pressure tap is clogged for some reason. I am starting to think that it is in the fuel delivery system.

JohnBuckner

My Feedback: (1)

Classic symptoms of Good practices in the vital tank to spraybar relationship having not been meet.

Even if you turn it over for starting or use Hemostats up to the minute of cranking in flight under the infuence of G load its likely at low throttle eratic running will occur. Some engines may tolerate this better than others due to the design taper and thread count of the needle if a conventional type.


John