Earlo
Well-known member
I have a 1973 Johnson 20R73A that has gear case issues. It was stuck in forward gear a couple of weeks ago. I tore down the lower unit and the forward gear and prop shaft were barely fused and were separated pretty easily in a press. The mechanic that did that for me said the shaft and gear should clean up with some emery cloth, which they did.
The other issue was that the forward bearing dowel had sheared off. I replaced the dowel, cleaned everything and got the gear case spinning again and reassembled it, took it to the lake and tested it for a 1/2 hour without issue. When I was loading on to the trailer, I unplugged the fuel line and was running the gas out of the motor. It was in gear, and pushing the boat against the trailer. Then I heard a single "THUNK". I backed off the throttle, shifted the motor a couple of times before it ran out of gas. All seemed okay.
This weekend I took it out again, and about every 30 seconds or so, when at more than 1/3 open throttle it would thunk and feel like I hit a stump. I tried adjusting the shift lever several times, but no luck. I took it home and took the lower unit apart, flipped the clutch dog around(one side has slightly less wear), and still the motor would clunk like hitting a stump when the rpms were brought up.
I'm pretty sure the dog needs to be replaced. My question is do I have necessarily have to replace the forward gear as well? The gear looks okay to me, certainly compared to the wear that the dog is showing. I found a new omc clutch dog and cradle for $107. The gear set is $385 which is more than I'm willing to dump into this thing.
The other issue was that the forward bearing dowel had sheared off. I replaced the dowel, cleaned everything and got the gear case spinning again and reassembled it, took it to the lake and tested it for a 1/2 hour without issue. When I was loading on to the trailer, I unplugged the fuel line and was running the gas out of the motor. It was in gear, and pushing the boat against the trailer. Then I heard a single "THUNK". I backed off the throttle, shifted the motor a couple of times before it ran out of gas. All seemed okay.
This weekend I took it out again, and about every 30 seconds or so, when at more than 1/3 open throttle it would thunk and feel like I hit a stump. I tried adjusting the shift lever several times, but no luck. I took it home and took the lower unit apart, flipped the clutch dog around(one side has slightly less wear), and still the motor would clunk like hitting a stump when the rpms were brought up.
I'm pretty sure the dog needs to be replaced. My question is do I have necessarily have to replace the forward gear as well? The gear looks okay to me, certainly compared to the wear that the dog is showing. I found a new omc clutch dog and cradle for $107. The gear set is $385 which is more than I'm willing to dump into this thing.