Dang engine!

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Lee B - 30 Jun 2009 20:22 GMT

Dang engine! My OS 75 two stroke. New OS #8 plug. Back flushed the carb.

Recently (with no crashes) this engine will NOT idle. The best I can get is
an idle that varies between 4000 and 8000 RPM measured (Rum Rum Rum -- like
a kid on a motorcycle). I have tried resetting the idle screw to no
avail -- and I actually followed the directions in the manual.

My troubles began with the engine dying at low RPM like it was WAY too rich
and the plug fire was being put out. This was before I fiddled with the
mixture screw. After fiddeling the engine will -- sort of -- idle, see
above.

Any ideas? New carb maybe (darn things are nor cheep)?

Thanks, Lee

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Chris Dugan - 30 Jun 2009 22:08 GMT

> Dang engine! My OS 75 two stroke. New OS #8 plug. Back flushed the
> carb.
[quoted text clipped - 13 lines]
>
> Thanks, Lee

My best guess would be check for an airleak; most likeley around the
front bearing. Apart from that is the carb sat tight to the crankcase and
is it and all its fittings secure.

How old is the engine in gallons of fuel and are the bearings the
original?

Signature

Chris

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Mr. Eastman - 01 Jul 2009 14:52 GMT

> > Dang engine! My OS 75 two stroke. New OS #8 plug. Back flushed the
> > carb.
[quoted text clipped - 23 lines]
> --
> Chris

I agree. check all the usual suspects...
Cracks in fuel lines - especially where they slide on the metal bits.
Cracks in fuel tank.
Clogged klunk or filter.
Head gasket.

--Mark

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Lee B - 01 Jul 2009 17:13 GMT

Air leak?? Does that include a missing screw that was supposed to lock the
carb to the engine body -- and created an EXTRA air hole??? Engine was side
mounted with the missing screw on the bottom side where I did not see it
until I took the carb off for cleaning!!

Thanks guys

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Tom Minger - 01 Jul 2009 01:42 GMT

Adjust the valves....

> Dang engine! My OS 75 two stroke. New OS #8 plug. Back flushed the
> carb.
[quoted text clipped - 12 lines]
>
> Thanks, Lee

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Vance - 01 Jul 2009 05:21 GMT

> Adjust the valves....

There are no "valves" to adjust on a two stroke I believe. :-)

>> Dang engine! My OS 75 two stroke. New OS #8 plug. Back flushed the
>> carb.
[quoted text clipped - 13 lines]
>>
>> Thanks, Lee

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To reply by email: vhoward1122 at gmail dot com

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Tom Minger - 01 Jul 2009 22:04 GMT

Doh............

Read once for jist; read twice to get all the words right.

Err..........don't try to adjust the valves :-)

>> Adjust the valves....
>
[quoted text clipped - 17 lines]
>>>
>>> Thanks, Lee

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Model Forum / Radio Controlled / Air Models / July 2009

Dang engine!