knocking sound

tom24

Seaman Apprentice
Joined
Feb 26, 2004
Messages
33
My 84 50 hp evinruide has a knocking sound when the flyweel is turned back and forth by hand.Is this a main bearing problem? :mad: <br />Thanks,Tom
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: knocking sound

Could be, Tom, more likely a rod or piston but not proof that there is anything wrong.<br /><br />Does it run? Does it knock when running?
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: knocking sound

Could be the timer base is sticking and moving back and forth with the flywheel. Don't know how loud of a knock you have, but it's a thought. Check it out...
 

Goodoleboy

Chief Petty Officer
Joined
Nov 20, 2003
Messages
555
Re: knocking sound

Hi Tom!<br /><br />Not necessarily..any dang thang machical will make uh bit uh "noise"...when ya twist it back an forth.<br /><br />Ya got uh lot ov machinical joints in this motor and others tu for that mater.<br /><br />Thats clerance uh twik...the mateing parts. Thars awl ways uh bit of clearance...aka...slak...between.stop and stop.<br /><br />How much is to much....Thats the question!..<br /><br />How bout is!...start it up...if it idels fine...put in the lake...if it runs good..<br /><br />This is what idd do if it was mine....you do as ya please!
 
D

DJ

Guest
Re: knocking sound

tom24,<br /><br />It depends on how loud it is. Outboards have relatively loose fitting needle and roller bearings as opposed to automotive friction type.<br /><br />Some "chink. chink, chink" will always be heard when rocking the flywheel back and forth.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: knocking sound

hello<br /> test the pistinrod/wristpin for excessive motion, most needle bearing assy use a .0005" tolerance. most sleve type insert bearings run.0025-.004 clearence. auto is so sloppy it aint funny. anyway rotate the engine in its normal direction of rotation with the plugs out. when the piston comes up the starts back down stop and hold the flywheel. put a #4 phillips on the piston crown and push. if any slack is noted its time for a tear down. but if all your doing is shaking things it will rattle and clunk all over. 2 srtokes dont slowly wear out like 4 strokes. the mains in my chebby sound like a kenmore washing machine in the morning. it has 290K miles on it. if it was a two stroke with bearings that loose it would have tossed a rod long ago. usually by the time you hear the knock its toast. check carefully. you may have a problem or you may be creating one. <br /> good luck and keep posting
 

Goodoleboy

Chief Petty Officer
Joined
Nov 20, 2003
Messages
555
Re: knocking sound

Rodbolt!<br /><br />Ats bullpoop...and you know it son.....Iam sixtey damn years learnd..They aint now way in heck...That uh two stroke....will out live uh four stroke.,...!<br /><br />Ive got an ole tractor....runs good..1950 model<br /><br />I aint pickin uh fite....realy I aint....so I aint gona argue wit ya!....Ifin ya post back....I quit....You have uh lot uh good stuff on hear..to yar credit<br /><br />But ifin ya thanks....Uh four stroke aint better...Yar rong!<br /><br />Lee!
 

Solittle

Fleet Admiral
Joined
Apr 28, 2002
Messages
7,518
Re: knocking sound

I'm gonna sit back & listen - - err - -- - watch this thing.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: knocking sound

hahaha goodoleboy.<br /> either ya caint reads much no good orn ya aint a comprhenden what I wuz a sayin. I say paya attenshun to me boy. I sez that a two stroke wont wear out slowly and run werse and werse like a 4 stroker will. I ran an old chebby with a flat intake cam lobe for 3 yearns. a two stroke will wear a bit then selfdestruct, they are high performance precision machines. but they dont tolerate any out of spec tolerances be it fuel, timing, cooling water or airfuel and oil fuel ratio's., miss any of them a bit and its a smoker. I have seen cars detonate so bad they actually slowed down going up hills and run like that for years. a detonation problem like that on a modern 2 stroke and it will eat off the piston lands in short order. so I in no way said any motor would out last anyother. I know of shortlived 4 strokes as well as 2 strokes and a buddy of mine over at the J-D house stays busy with dem broke tractors:) :) . we aint no maytags mans dats fo sur. all I was trying to point out is that if there is any motion in the rodbearing or wristpin area and you run it it will disentergrate and odds are will destroy the block and crank.<br /> good luck and keepem a postin
 

Indymike

Petty Officer 1st Class
Joined
Aug 17, 2004
Messages
364
Re: knocking sound

Man I laughed so hard reading this one I thought it worth a bump just for the humor.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: knocking sound

see<br /> I is bylanguall<br /> I speaks anglish and sothern :)
 

umblecumbuz

Lieutenant Junior Grade
Joined
Sep 25, 2004
Messages
1,062
Re: knocking sound

Oh boy!<br /><br />This one's for my wallchart for sure!<br /><br />I don't care a jot how it turns out ... but it'll give years of laughs to all my customers!!<br /><br />Thabnks fella's for a bright start to the year!<br /><br />Ciao (Lee - that's Eyetallyan for see ya!)
 

fireman57

Captain
Joined
Aug 24, 2004
Messages
3,811
Re: knocking sound

boltbreaker, where at in So. eastern Ill? I'm in the very SW of Indiana. Fish the Wabash and Ohio.
 
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