Mercury 75 HP slipping in gear

[buzzking]

Forward gear is fine. When put in reverse at idle it makes a clicking sound until you apply the gas, at that point it slides out of gear. Since forward is okay, it would appear to me that the shift cable needs adjusting. Getting the boat tonight. This sound about right? Also, in the case it is the dog clutch are there any insightful instructions about changing that? Been told I need a few special tools? TIA.
Serial Number: 0G086583

 

[Chris1956]

Re: Mercury 75 HP slipping in gear

To adjust the shift cable, you disconnect the shift cable barrel nut, place the throttle handle in neutral, and move the shift slider into neutral. Now you adjust the barren nut to fit it's clamp.

These are only proximity instructions, since I was unable to figure out the year for that motor based upon the serial number. You might doublecheck it. The 75HP mercs last serial number sequence started with 0B

 

[buzzking]

Re: Mercury 75 HP slipping in gear

thanks for the reply. Its a 95 model.

 

[buzzking]

Re: Mercury 75 HP slipping in gear

Okay, update, got the boat here, have the shift linkage off. Guy told me wrong. When in nuetral turning the prop you here a very loud clanking at the head of the prop shaft. When engaged in reverse it locks in and turning the prop results in turning the motor over. When in forward gear it slips considerably with the same clicking at the head of the prop shaft. Dog clutch?

 

[Jeff_G]

Re: Mercury 75 HP slipping in gear

More than likely both the clutch and forward gear will need replacing. The pinion and forward are usually replaced as a set.
You will need some special tools to disassemble the lower unit.
Adjusting the cable is a short, real short term fix. If you adjust for more forward you will lose reverse. You will lose forward anyway.

 

[buzzking]

Re: Mercury 75 HP slipping in gear

okay so I have the L/U apart. Carrier bearing out, L/U laying in the floor. Seals are trashed and water pump is shot to hell but I still can't find the root of the problem. The dog clutch is mint, slides perfectly, all the gears are sharp and not rounded. The carrier came out with the dog and the nipple on the end with the ball bearing under still intact. Drive shaft turns the forward gear perfectly with the carrier out. When I put the carrier back in I get the slip. Any more insight? I apologize for being a rookie here and I may be slightly in over my head but I'm dying to learn how all this works and how to diagnose the problem. Any insight would be greatly appreciated.

 

[Jeff_G]

Re: Mercury 75 HP slipping in gear

When the engine is running the pinion gear is turning the forward and reverse gear at the same time. Shifting is accomplished when the clutch is moved back and forth on the splined prop shaft. The gears float on the prop shaft, only the clutch is splined.
Remove the bearing carrier. Put the prop shaft with the clutch back in. Hold pressure on the prop shaft and shift into forward and see if the clutch engages forward gear. If it doesn't the problem is either the shift shaft is aligned wrong or there is excessive wear in the shift parts in the prop shaft. Make sure they are clean and not binding in the shaft.
If the clutch engages properly yet it doesn't with the carrier in then there is probably a lot of slop. Make sure the carrier is seated all the way.

 

[buzzking]

Re: Mercury 75 HP slipping in gear

The L/U came off no worries, I have the Merc manual en route. The shift drive did not come out with the L/U. It appears to be stuck in the top spline. Does this need to come out or can I simple leave it in while I continue to hopefully diagnose the problem?