Rough running engine

by Robert Raczynski in General Tech Discussion 8 years ago

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Re: Rough running engine

by Roger Lee » 8 years ago

Roger Lee

125 5.12k 4.53k

Sinking floats (causing flooding and needs replacement), bad carb bowl gasket (needs replacement), bad float armature adjustment height (needs adjustment, bad needle valve (needs replacement) or a combination

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

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Re: Rough running engine

by Robert Raczynski » 8 years ago

Robert Raczynski

1 5 0

Ok, installed carb kit and o-rings to intake and carb. No change. Did see exhaust staining on bottom of #1 cylinder but no watrr or oil showing. What the heck. Hooked up gauges to balance carbs and the 1&3 side does not change with throttle change, stays about 5 in Hg. Hmmm. Also, compression on all cylinders is 79 so rings and valves are ok. No indication of exhaust leaking from muffler or exhaust piping. Exhaust staining, light tan coloring, is on fins on # 1 cylinder only. It's a puzzle.

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Re: Rough running engine

by Roger Lee » 8 years ago

Roger Lee

125 5.12k 4.53k

You either have a gauge issue on the right side or a carb issue or throttle cable issue that you haven't found yet.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

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Re: Rough running engine

by Robert Raczynski » 8 years ago

Robert Raczynski

1 5 0

why the exhaust staining on the bottom of #1 cylinder? No sign of exhaust leak at the obvious places. Weird. Switched gauges and hoses around, checks out ok. Problem is on #1 &#3 side. Again, cylinders 3,4, & 2 have completely clean fins, not #1. Kitted the carbs, great shape, although some of the O-rings broke pretty easily when taking them off. Followed the video to the tee. Did compression checks, all cylinders 79#. Sprayed starter fluid on intake areas and carb with no increase in rpm. If the vacuum only goes so high and no higher could there be a blockage in the exhaust somewhere? Spark plugs all look good. If there's nothing more to do where do I send it? I guess that's what's next. Right? Definitely would rather fix myself but...

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Re: Rough running engine

by Roger Lee » 8 years ago

Roger Lee

125 5.12k 4.53k

A few items to check.

Did you remove the butterfly valve plate and replace that "O" ring. If you did , did you make sure the butterfly had the center punch mark on the top and facing outward? Is the butterfly seated squarely and straight in the carb opening? The screws can be tightened even with this plate out of alignment. It should make a perfect seal around the edges without any spaces. Are you sure the piston diaphragm is in the proper notches on the piston and outside edge of the carb? Are you sure the choke is faced in the correct direction. Look at the outside of the shaft and make sure the center punch mark faces the part that looks like a piece of pipe coming out the choke body.

If you have grey exhaust somewhere you have a leak that needs to be found..

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

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Rough running engine

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