1990 merc 3.0 flapper vaulve

[boaterntexas]

My 1990 3.0 mercruiser rattles occasionaly, most of the time on when first started, it sounds like it is comming form the , back , lower , left hand side of the motor. from reading other post I believe it may be my exhuast flapper, is this a common problem, nad is there ever a time when you should replace or repair it becuase of the rattle?<br /><br /> Thanks,<br /> THomas

 

[elpaso]

Re: 1990 merc 3.0 flapper vaulve

To rattle at idle for an older boat is common.<br />The sound should stop at higher rpm. when the<br />flapper is held open buy exhaust pressure.<br />When new the flapper had a soft coating -that <br />with age, has worn off.

 

[boaterntexas]

Re: 1990 merc 3.0 flapper vaulve

THANKS, I've atcually heard of theese things falling off, cuasing the motor to ingest water.. is there standard preventive maintance that should be done on the flapper?

 

[elpaso]

Re: 1990 merc 3.0 flapper vaulve

Only maintance is to replace, to do so the<br />exhaust riser has to be removed.<br />I would wait till the end of the season.<br />A flapper can rattle for a long time with no<br />ill efects. <br />It is a simple job that anyone can do.<br />But - break a bolt off - and you have big trouble.<br />If boat is running good- no temp. problems -<br /> - never kick a sleeping dog.