FlyCubs

I have two OS MAX 60 SR engines that are in reasonably good shape but both suffer from the same problem.

I can't keep the idle mixture set properly. I believe there are two things happening to cause this. They both need gasket sets and the o-rings in the carb are old and worn so air leaks in at a different rate when the engine is warm or cold. I have also witnessed the idle mixture screw turning all by itself when the engine is at relatively high RPM.

These engines belonged to my Father so they have a fair amount of sentimental value to me and I would like to get them running in good order and add them to my stable of OS engines. I just bought a FS 91S II to put in my airplanes while I get the old 60's running.

If you do not have parts available for these engines, can you at least point me to an engine repair shop that does? The worst case scenario is that I will have to make the gaskets but I can't make o-rings. Do you have any idea where o-rings of this size can be purchased?

Any information will be truly appreciated.

Thanks...Steve

Bax

My Feedback: (11)

If you wold look at the carb and see what carb you have, it's likely that O.S. still has o-rings that will fit. They are parts that are used in many current carbs.

O-rings would most likely be the reason the idle mixture won't hold.

FlyCubs

Thanks for the reply Bax. I certainly hope the o-rings are available. I've enclosed a couple of photos of the carb. Can you identify it?

Thanks,
Steve[sm=biggrin.gif]

Bax

My Feedback: (11)

The carburetor should have a number on it, usually in a small oval patch near the "O.S." on it. We can't tell from the pics which carb you have. Several carbs have shared basic configurations, but had different internal parts.

FlyCubs

Bax,
There is a number pad on the front of the carburetor but there is no number on it as you can see in the attached photos. I've taken out the slide, idle mixture screw, spring and the needle valve and taken photos in hopes you can identify the o-ring I need. Thanks for your efforts

Steve

Bax

My Feedback: (11)

OK, from an early 80's parts book we have around, the O.S. Max .60 FSR came with a #7B carb, but we'd not be able to confirm that your carb is a #7B, since we don't have any pictures or diagrams for comparison.

On the #7B carb, the needle o-ring is:

OSMG7388 24981837 O-RING NDL FS/FX/LA $4.49

The idle valve o-ring is:

OSMG7372 24881824 O-RING IV/PRC #6H $2.99

Those parts are still used in a wide variety of O.S. Max engines, including current-production units. They may work in your engine's carburetor. These parts can be ordered through any hobby retailer who sells O.S. Max engines and accessories.

Hope this helps.

FlyCubs

Wow! Thanks Bax! This is why I buy OS. Unbelievable support. I'll order these parts and give it a try.

Thanks for all your efforts!

Steve

fishkillbill

My Feedback: (4)

What size prop does an OS Max 60 take?

Bax

My Feedback: (11)

Start with an 11 x 7 propeller.

aerowoof

Bax

I have the same engine but it needs a drive washer.any chance that a current engine uses the same setup?