Clunk when shifting - The Hull Truth

jessily · 05-19-2009, 06:16 PM

Have a new to me 2000 Merc. 90 HP 4 Stroke that makes a pretty big clunk when shifting between reverse and forward or back again. Other wise shifts fine and runs well but seems a lot stiffer in shifting than any other outboard I have owned?

A1 Outboard · 05-21-2009, 06:11 AM

You didn't mention if you have a stainless prop. Outboards all tend to clunk to a greater or lesser degree. A stainless prop or high idle speed will make this more apparent. Find someone with a similar rig and see how it sounds.

davidkuhlmann · 05-21-2009, 07:00 AM

Also check the end play of your prop. Some of the flo torq hubs have slack in them. To fix this most simply grind down the hub center piece so that it eliminates the end play. Just grab your prop and push in and pull out. If there is any play this is probably the cause of your clunking noise.

The clunking should not really cause any problems since there are many Mercury's out there doing this. I however would get rid of it IMO. My Verado does not have the end play problem with my SS Tempest prop but did with the aluminum prop that it came with.

jessily · 05-27-2009, 07:40 PM

Thanks Guys. I will check the prop (Stainless) next time out. Ran it all day on Memorial day and it ran great except for the clunk sound which hopefully I can correct after checking the play on the prop....