Symptom of reed valve failure?

mikec

Seaman Apprentice
Joined
Jun 6, 2001
Messages
40
Anyone know what the symptom of reed valve failure is? I suppose this would be when a reed doesnt seal all the way. Would the failure be RPM sensitive? Can it be diagnosed without taking the carbs off?
 

12Footer

Fleet Admiral
Joined
Mar 25, 2001
Messages
8,217
Re: Symptom of reed valve failure?

Low compression is one symptom.<br />Spitting fuel from the carb,or air pressure fealt when hand-choking it.
 

ODDD1

Lieutenant Junior Grade
Joined
Jan 23, 2001
Messages
1,054
Re: Symptom of reed valve failure?

A broken/ leaking reed in a multiple cylinder engine will cause that cylinder[with the bad reed] to act lazy.....depending on the size of the leak, the engine could run fine at WOT, but will always be lazy at idle/part throttle....a broken reed allows the intake charge being compressed in the crankcase to bleed away....so that particular cylinder will act lean...an extra shot of fuel down the bad cylinder will generally make it fire briefly.....an experienced tech can usually pick up a bad reed just by listening at the carbs when the motors idling...they make a distinctive sound...an engine with a bad reed will have the same compression in the cylinder as a good one would, unless the broken off piece caught in the piston/rings and damaged them....
 

mikec

Seaman Apprentice
Joined
Jun 6, 2001
Messages
40
Re: Symptom of reed valve failure?

Thanks so much! Im chasing a low/mid RPM "miss fire/boggy cylnder" problem and will follow this avenue of troublshooting. Thanks again. -mikec
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
35,927
At idle speeds a bad reed valve would surely cause poor idle.----If engine will not go past 4200RPM there are other problems !------Does spark jump a gap of 3/8" (1 cm ) on all leads , yes or no ?
 
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