1977 Mercury 850- Lower Unit grinds in reverse

[tallcanadian]

I'm looking for some input on this issue. In reverse, the lower unit grinds like it's going in and out of gear. It grinds loud, then soft, loud, then soft. Very weird. In forward, no issue at all. I know that the PO replaced the impeller before he sold this to me, so I'm wondering if he overlooked something when he replaced the lower unit. Any input is appreciated. Also when I splashed it for the first time last week I got it up to speed once but it started to over rev, like the prop had spun or slipped. I eased back on the gas and it stopped. The cavitation plate is level with the bottom of the boat. I don't have power trim, yet. but it's only on the second hole. I'm not sure if both issues are related or not.

 

[Chris1956]

The second trim hole is correct for most boats. That is not likely your issue, When the motor is in neutral, the shift slider should be in about the center of it's travel. Best test is to water test reverse, with the shift cable disconnected. Push the shift slider rearward until reverse catches. If the grinding is gone, either the shift cable is out of adjustment or the controller is not providing enough shifter travel.

 

[Faztbullet]

More likley cam follower tip worn down, install the new style follower with the 3 balls (#445321) and will it.

 

[tallcanadian]

More likley cam follower tip worn down, install the new style follower with the 3 balls (#445321) and will it.

Sorry for sounding silly here, but where on the motor is that. LOL. I've been searching part guides but can't seem to find the part name or number.

 

[Chris1956]

The cam follower is inside the gearcase. Hopefully that is not your issue, as the fix is a bit tricky for the average bear.

 

[Faztbullet]

Its in the end of propshaft and simple to install, the difficult part is removing bearing carrier and nut...part # 44532a1