When should I worry??

boatn_bob

Cadet
Joined
Jul 9, 2003
Messages
7
When should I worry??

Well again I'm new here so hang with me please. My motor >. 1990 3.0 lh rotaion mercuiser.<< I have been hear a random rapping, scratching noise. It seems to be happening more often that in the past. When out of the water, this very load noise seems to be comming from the left bottom rear of the motor, near what I thought was the atlernator, now I'm thinking it is the starter. after looking a listening a little more, is sounds like it is comming fomr the oil pan. <br /> My initial guess was flapper valve.. My hopefull guess is flapper, but as load as it is it's starting to worry my, and it will show itself anywhere from 700 rom :: 3000 rpm. Typically at start for atleast 5 :; 10 secs then it goes away and maycome back at random. All this testing has been done outside the wwater with muffs on, however I did notice it @ startup when I was on the lake last time.<br /><br /> My question is.. any guesses as to what this could be, and should I be worried about it since it comes and goes. again, I'm not sure eactly where is comming from but I do know it is really load, and seems to come from the bottom part of the engine. and is reall noticeable at start up, even before the engine fully cranks up..<br /><br /> Thanks,<br /> Distressed BOB
 

denniz

Senior Chief Petty Officer
Joined
Aug 21, 2002
Messages
743
Re: When should I worry??

Re: When should I worry??

exhaust shutters can make a noise at anytime.(rpm)why not replace it and see if the noise goes away.If it doesnt then start worrying.
 

boatn_bob

Cadet
Joined
Jul 9, 2003
Messages
7
Re: When should I worry??

Re: When should I worry??

i guess thats what I should do. I seen a pari on ebay for like 31.00 is this a fair price?
 

denniz

Senior Chief Petty Officer
Joined
Aug 21, 2002
Messages
743
Re: When should I worry??

Re: When should I worry??

3.0 doesnt have a pair it has 1. Id take your serial # to the nearest dealer and get the right stuff. No telling what youll get off ebay.Shouldnt be more than $30.00 though. Pull yours and see if you need one. If any part of it shows metal replace it.
 

boatn_bob

Cadet
Joined
Jul 9, 2003
Messages
7
Re: When should I worry??

Re: When should I worry??

I know, I should get a repair book, but where exactly can teh flapper be found on a 1990 merc 3.0 right next to the transome?
 

denniz

Senior Chief Petty Officer
Joined
Aug 21, 2002
Messages
743
Re: When should I worry??

Re: When should I worry??

under the elbow in the exhast tube and yes you need a book.
 

boatn_bob

Cadet
Joined
Jul 9, 2003
Messages
7
Re: When should I worry??

Re: When should I worry??

AWWW... RELIEF pulled the flapper, heard no noise, replaced falpper, heard lots of noise.. atlest I know the source.. I really funny, becuase that sound does not seem like it is comming from the exhuast elbow. funny how that works..<br /><br /> Bob
 

crazy charlie

Vice Admiral
Joined
May 22, 2003
Messages
5,602
Re: When should I worry??

Re: When should I worry??

Boatnbob,to check where a noise is coming from for future reference,Take a wood broom stick,place it on the part in question and stick the other end in your ear.I know it sounds weird,but it works great.You will know in a second if you have located it or not.You will hear it loud and clear. Charlie
 

boaterntexas

Petty Officer 1st Class
Joined
Feb 4, 2003
Messages
254
Re: When should I worry??

Re: When should I worry??

man this help me with my problem as well,, thanks guys.
 
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