275 reverse catch/latch

[sailingseven]

This summer I replaced my prop with a volvo ss 14.5 X 19 which is much heavier. Soon after I began to hear a loud clunk when shifting into reverse. When I tried to recreate this sound on land with muffs it shifted smoothly with no noise. My question is could this clunk be the drive in water striking the reverse latch? There is play in the drive before the catch grabs hold. Any thoughts would be appreciated.

 

[Don S]

Re: 275 reverse catch/latch

What is your engine idle rpm? What engine. Many times drives will clunk into reverse and not forward because the fwd clutch gets used more than the reverse and lets it slide into gear smoother. Idle rpm above 700 usually makes it worse. The SS just puts up more resistance in the water.

 

[sailingseven]

Re: 275 reverse catch/latch

Aq 131a with idle rpm at 850 on shop tach. Thanks for the quick reply.

 

[Don S]

Re: 275 reverse catch/latch

You're going to have the clunking with that engine and it's high idle speed and using a SS prop.

You might be able to reduce it some by re-shimming the upper gear box. I would bet after this many years, the lower washer that hold the circlips has probably bent over and allowing excess gap under the top nut on the vertical shaft. It should be .004 to .020, when they get up around .040 or more, they can start clunking into gear even with an aluminum prop.