1968 18hp evnrude lower unit

lower unit feels like it is s

lower unit feels like it is shifting gears or hitting something while under way.
I have also had to replace the shear pin twice recently for no apparent reason.
Any help would be appreciated.

"Al.... That jumping sensation

"Al.... That jumping sensation or feeling like you're constantly hitting something is caused by a engine that is jumping out of gear, then being slammed back into gear. In the lower unit, there is a shifter dog that rides on the propshaft splines which has lobes on the front and back portion of it. When you shift the engine into forward or reverse, that shifter dog is forced into the respective gear which also has lobes on it. The gears are turning constantly when the engine is running. When those lobes engage, the gear causes the shifter dog to turn which is splined to the propshaft, and of course the prop then turns. Those lobes on the gears and the shifter dog must be in perfect condition in order to stay engaged.

Many boaters have the thought that if they shift into gear slowly, they are taking it easy on the shift components, but actually the opposite is true. When shifting slowly, that allows the lobes on the gear and the shifter dog to clash a great number of times. This results in the lobes having their right angle corners worn off to a rounded condition. At a low rpm, usually the shifter dog will stay engaged, but as the rpms increase, the built up pressure forces the dog out of the gear due to the rounded condition mentioned above.

This rounded condition of the lobes can be caused by the slow shifting mistake as above, or by worn linkages within the engine, or by incorrect shift linkage adjustments. Whatever the cause, I wish you luck.

Joe "

" Joe, thanks for the advice.

" Joe, thanks for the advice.
I checked the dog and there is some wear on it, I reversed it as there was no wear on the other side.
The proppeller on the other hand has a lot of wear in the slot where the shear pin sits.
I will try to have the prop repaired or replace it before I venture out again.
Will reversing the dog cause me any further problems?
Thanks again for your help.
Al "

Error Encountered Here. Post I

Error Encountered Here. Post Is Listed Below.

" Al.... That shifter dog sho

" Al.... That shifter dog should have a grove machined into one end that would face forward gear and it can not be reversed. If a new one is installed backwards, it will cause a jumping out of gear problem resulting in damage to the new dog and gear. A new shifter dog lists for about $30.00. If you decide to replace that item, I have one left in my remaining stock that you can have for $23.00 which will include shipping.

Joe (30+ Years With OMC) "

"Sorry it took so long to get

"Sorry it took so long to get back to you but the wife had put her foot down and I had to take care of multiple honey do's.
Joe I would Like to have that shifter dog.
Send me the info for purchasing this from you.
[email protected] and I will get back to you asap.
Thanks again for all your help.
Al"

Re: " Al.... That shifter dog sho

Do you still have the clutch dog or have you sold it? Would it work in a 72?