Clicking/Clanking from lower unit while in reverse

[scottjima]

2005 Mercruiser 4.3L 190 Carb - Alpha 1<br />38.5 hours on engine - Lower unit serviced w/ Mercury green fluid twice. No water in oil.<br /><br />When run out of water, the lower unit will clank while in reverse. This has gotten worse over last season. Boat is at dealer now for several warranty items including this. The writer seemed to think it was allot more than a cable adjustment...<br /><br />Any ideas?

 

[EricYourHost]

Re: Clicking/Clanking from lower unit while in reverse

Check the rpm's in reverse and the slow reverse micro-switch is engaging. Do not ease in fwd or rev. Make sure you have a red cable instead of a black shifter cable.

Use the proper fluid and replace your water pump every year. Never crank or tun the engine on when no water is in pump unit.

 

[Mischief Managed]

Re: Clicking/Clanking from lower unit while in reverse

Assuming reverse is fully engaged:

Take the prop off and try it again. It might be something as simple as the prop accelerating/decelerating, and taking up lash in the drive on each power pulse of the engine. It would be worse with a heavier SS prop than it would be with an aluminum prop and would also get a little better with more engine speed. In the water, there would be enough drag on the prop to keep this from happening.

 

[Don S]

Re: Clicking/Clanking from lower unit while in reverse

Ya gotta love the new guys with wierd answers,

slow reverse micro-switch is engaging.

Never heard of one of those before. Sure you didn't mean the shift interrupt switch? Besides, they shouldn't be doing anything going into gear.

Make sure you have a red cable instead of a black shifter cable.

The red/black cable issue was an OLD (1986-87) cable problem for OMC. Mercruisers have always used black cables, never red.