1992 150 johnson noise

hydrasports

Seaman
Joined
May 8, 2002
Messages
72
My mechanic mentioned that he hears a slight tapping noise on my 1992 150 johnson and bets its a wrist pin.He says not to worry about it and that its probably just from many hours of use etc... when wrist pin noise occurs (I dont hear it,bad hearing) is almost ammediate that it will break down,or could the engine possibly go some hundreds of hours before a major rebuild is needed ? Mechanic advised against opening up engine just for that light noise since the engine runs strong and smooth.Should I just wait it out until a real rebuild is needed ? thanks
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: 1992 150 johnson noise

If its a loose pin or a bearing going bad you can take the plugs out and rotate the flywheel clockwise. (Youll have to remove the flywheel cover naturally) Hold a screwdriver aginst each piston to know when its coming up. In the middle of the up stroke, remove the screwdriver and rotae the flywheel back slightly. Use the screwdriver to see if you can push the piston back. If you can, a wrist pin may be coming loose in the piston especially if the motor has been lugged. A rod bearing may be going bad. The piston should move with the flywheel with no play at this point. <br /><br />Sure you can ignore it but if something is wrong and the motor locks up, can you walk home at that point? Besides it may just be piston slap and the pin and bearings are OK. If it was mine I'd want to know.<br /><br />Good luck.
 

Beernutz

Petty Officer 1st Class
Joined
Aug 14, 2001
Messages
287
Re: 1992 150 johnson noise

D's right, but make sure you know the difference between actually pushing the piston back or simply rocking it on the wrist pin. Your noise could just be a little piston slap. If, as you indicate, the noise is very slight, the movement may be hard to detect. Does it disappear or get worse when you increase the rpm's?
 

hydrasports

Seaman
Joined
May 8, 2002
Messages
72
Re: 1992 150 johnson noise

thanks for the responses gentleman,Now that I knew what to listen for,I took the cover off and can hear a ticking, very fast tick tick tick tick,kinda sounds like an electrical tick if that makes any sense,but Im pretty sure its coming form the top port cylinder.I did the screwdriver trick and didnt seem to budge.Maybe this old lady has seen her best days, but so far she runs strong. I hate thinking/knowing its a matter of time.
 
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