MERCRUISER 140 VIBRATION

[gary w m]

I HAVE A VIBRATION IN MY 16 FOOT 4 WINS FOUND BAD MOTOR MERCRUISER 140 AND ALPHA DRIVE AND REPLACED IT WITH FRESH REBUILT MOTOR AND REBUILT DRIVE AND I STILL HAVE THE SAME VIBRATION BETWEEN 2000 AND 2500 RPM . CHECKED ALIGNMENT AND REPLACED THE COUPLING, ALL IS GOOD BUT STILL HAVE VIBRATION AT 2000 TO 2500. HAS ANYONE EXPERINCED THIS. OR CAN HELP WITH ADVISE.

 

[Bondo]

Ayuh,.... Welcome Aboard,.... Turn off yer cap-lock, nobody likes to be YELLED at,....

Are ya runnin' the same prop,..??

 

[Scott Danforth]

Welcome aboard

in addition to the prop, are you running the same u-joints and gimbal bearing as well?

 

[fishrdan]

Vibration at 2000-2500 RPM on the water and in neutral, or only in forward gear?

As suggested already, If the prop hasn't been replaced, that's the first place I'd start. Also, what are you torquing the prop nut to and does the prop use a replaceable hub, like a Flo-Torq?

 

[gary w m]

sorry about cap lock. I have a prop at the prop rebuild shop ready to pick up tomorrow,but the vibration is there in gear or neutral, Is it possible the rear mounts have gotten hard with age and not dampening the vibration. The motor has been totally rebuilt and the outdrive has been rebuilt with all mercruiser bearings gimble bearings and ujoints. The only thing that I used from the old motor is the fly wheel and the harmonic balancer.

 

[Rick Stephens]

You might pull the drive off and run the motor either with a garden hose stuck into the water passage on the bell housing or attached directly to the in port on the thermostat housing. See if the vibration goes away without the drive.

The rear mounts don't really have much in the way of damping - at the rear motor mounts the motor sits on a 1/4 inch thick piece of leather, believe it or not. Not a whole bunch else providing shock absorption. If you can use that word for a 1/4 inch thick leather washer.

3.0L motors are rough running compared to V6 and V8 motors. But shouldn't feel a lot of vibration like you describe. Has to be something we're missing....

 

[gary w m]

Thanks I will pull the drive and run the motor on the hose and that will for sure tell me where to look next.

 

[Scott Danforth]

you might want to double check your firing order and make sure you do not have a fouled dizzy cap.