1988 Nissan 55 Hp Transmission Problems

[Harritwo]

I was down south at my Dad's and went to take him out on his boat on the lake. We started the engine on muffs at the house and all was good. Went to the ramp, Backed down into the water, fired the engine off, shifted into reverse and came off the trailer. The Son went to shift in to forward to pull around to the dock so his grandpa could get in, and boat was still in reverse. Shut down engine and looked at all the linkages, everything is moving like it is supposed to. Fired the engine back off, Now boat is in neutral no matter what the shifter position is. Boat jumps into reverse regardless of what the throttle/shifter says.

After drifting away from the dock, dropped the trolling motor and motored back to the trailer. Winched onto the trailer and pulled up ramp. Went to the staging area, the shift linkage is moving all the way into the lower unit.

At this point, I pulled the lower plug of the unit and drained about 2 ounces of water, still with lots of oil, no metal shavings present. I put the plug back in and have not touched it at this point while waiting your feedback.

The engine/lower unit are still assembled. What is my next step, what am i looking for? Are parts available for this lower unit?

I have a 40 HP Nissan, Same vintage, will the lower unit bolt up? Will any parts interchange if they are still usable and new is not available?

Any help will be greatly appreciated. I hope that i am not the proud owner of a paperweight or new anchor.

George

 

[pvanv]

Re: 1988 Nissan 55 Hp Transmission Problems

You may have a rusty shift dog or broken spring. Possible rusted gears and or bearings. Once I get to the office this morning, I will see what may interchange or be available. Sounds like the LU needs a seal kit at a minimum, which may or may not be available. Just getting the old LU apart may be a challenge at this point.

 

[Harritwo]

Re: 1988 Nissan 55 Hp Transmission Problems

Paul, I had the LU apart last year, I changed the water pump. Can you PM me with your contact info, I have lost it.

George

 

[Sea Rider]

Re: 1988 Nissan 55 Hp Transmission Problems

There's a shift lever stopper which locks shift arm in place for F-N-R, that could be the issue if lever's bolt is loose ? check.

Happy Boating

 

[pvanv]

Re: 1988 Nissan 55 Hp Transmission Problems

That won't put water inside the LU.

 

[Sea Rider]

Re: 1988 Nissan 55 Hp Transmission Problems

Although it won't account for water intrussion on LU, if shift lever stopper is loose will account for shift moving onto any position it want's to lock in while engine is on, a matter to inspectl if bolt is tight ?

It seems you have 2 main issues, gear box issues + LU seal issues...

Happy Boating

 

[pvanv]

Re: 1988 Nissan 55 Hp Transmission Problems

You may have a rusty shift dog or broken spring. Possible rusted gears and or bearings. Once I get to the office this morning, I will see what may interchange or be available. Sounds like the LU needs a seal kit at a minimum, which may or may not be available. Just getting the old LU apart may be a challenge at this point.

Seal kits are not available for that oldie. If you pressure test the LU, you should be able to determine the location of the leak. Then cross your fingers that we can still get the appropriate parts.

Still, you will need to disassemble the LU to assess what rust damage may be in there.

There is a distinct possibility that you are at the end of the line as far as usefulness for this motor.

 

[Harritwo]

Re: 1988 Nissan 55 Hp Transmission Problems

I understand about the usefulness of the engine. Once i pull the lower unit, How do I pressure test the lower unit before disassembly? Is the procedure that same as for the Mercruiser? Were you able to see if the LU off my 40 HP would be a parts donor?

Paul, can you provide the procedure to pressure test and also how far to dis-assemble for inspection using the Nissan manual that i have? Any info is greatly appreciated and needed to determine feasability of repairs.

 

[Harritwo]

Re: 1988 Nissan 55 Hp Transmission Problems

Sea Rider, Please expand as to what you are referencing. When I move the remote control the cable follows the command. the rod running down the forward side of the engine is moving in both directions above and below the coupling. I am not understanding where this bolt that you are referring to is located.

 

[Sea Rider]

Re: 1988 Nissan 55 Hp Transmission Problems

Sorry, the bolt is located inside engine, next to shift lever mechanism, could be a problem if being a tiller model, in your case not an issue if having a remote box.

Happy Boating

 

[TOHATSU GURU]

Re: 1988 Nissan 55 Hp Transmission Problems

Pressure testing a lower unit is universal and no, the parts are not compatible.

 

[Harritwo]

Re: 1988 Nissan 55 Hp Transmission Problems

Thank you for that information Elvin. I will start tear down and pressure test soon, hopefully i do not have a new anchor and it can be repaired.