Can anyone tell me the difference between the FS40 and FS40S. I just bought a FS40 on ebay and I am trying to find the manual, but on the os web site they only list the FS40S which looks almost the same except for the valve cover.

Can I still get parts for this engine If this is an older engine ?

I noticed the carb has no low speed needle but uses a air bleed, will this result in a less reliable running engine?

The engine is all gummed up and does not turn very smoothly. I cleaned it with mineral spirits and oiled it. The bearings looked clean. Any other suggestions for cleaning it before I run it.

Thanks,

Marcel.

Marcel,

Proper cleaning would require a full disassembly of the engine. You'd scrub off any cooked-on or solidified resifdue with a very soapy solution of dish soap and water, and use 4-zero steel wool (also called "four-ought" or "0000"). Rinse under water as hot as you can stand with the bare hands, shake off and allow to air dry. Rinsing with alcohol will remove the water faster. Oil parts immediately, especially the steel parts. Make sure you don't get bits of steel wool in the bearings.

Reassemble your clean engine.

The O.S. Max FS-40 engine has been out of production long enough that we don't have an instruction sheet in electronic format. Please send an email to:

[email protected]

To request the price of a photocopied instruction sheet.

The air-bleed carb is fine. The engine runs very well with it.

Parts specific to the engine are no longer available. The engine has been out of production since 1984 or so.

Bill,

Thanks a lot for the info. I am hoping to test run it this weekend and see how it does.

Marcel.

Bill,

Well the engine is running just fine. I mounted it inverted in my little Waco bipe and it runs pretty good. I have trouble starting inverted, when I start setting the plane on it's wing, so now the motor is side ways, it will start fine. I have a feeling that the engine gets too much fuel. Also when idling after about 20sec or so it start run rough and will die after some time. I turned the airbleed needle out a lot but still see this. If I keep the glow driver on it idles much better. I can't do much about the tank position which might be a tad higher, any other suggestions.

Thanks,

Marcel.

Problems with inverted engines are common. It's because the glowplug acts as a sump at low to mid throttle settings. The liquid fuel tends to put out the fire. Side mounting eliminates those problems.

If the engine's getting too much fuel at idle, it sounds like the tank may already be too high. With a high fuel tank position, the engine will still tend to be too rich at low to mid throttle settings, but you'll just have to live with that. Lowering the tank will help a lot, but from your description, it's not possible in your model.

The centerline of the tank should be level with the centerline of the carburetor or slightly lower.