Lower Unit carrier question

[99yam40]

I would think it has something to do with how much you want to spend.

a bearing that has no problem, does not need to be replaced or modified, just cleaned well if it is in good shape

[Soundear]

That makes sense! At this point, the cost is not an issue since I went through hell to get that carrier off in one peice. Can you recommend a solvent and/or cleaning procedure prior to assembly? Previous posts mentioned “Pitting” where does that typically happen?
When I took off the water pump, I noticed a bit of rust around the upper driveshaft. I just changed those seals last year. The impeller looks perfect. Would you suggest I change the impellirvas well as the seals for safety sake?

[TownsendsFJR1300]

. Can you recommend a solvent and/or cleaning procedure prior to assembly? BRAKE CLEANER WOULD WORK FINE FOR CLEANING.

Previous posts mentioned “Pitting” where does that typically happen? IN THE MAIN HOUSING WHERE THE LARGE O-RING(S) WOULD RESIDE

When I took off the water pump, I noticed a bit of rust around the upper driveshaft. I just changed those seals last year. The impeller looks perfect. IF THE SEALS ARE THAT NEW, PROBABLY NOT NEEDED.

(PRESSURE TEST BEFORE ADDING OIL TO MAKE SURE IT DOESN'T LEAK).


Would you suggest I change the impellirvas well as the seals for safety sake?
THE IMPELLOR, WHY YOUR THERE, I'D REPLACE IT.

As for drive shaft rust, us the proper Yamaha WATERPROOF GREASE on the splines(NOT ATOP THE SHAFT), mid-section bushing (if equipped) and maybe a very,very light coating on the rest of the shaft to keep bare metal from rusting..

[Soundear]

My plan is to button this all up this weekend. I need to replace my lower seals; inspect and possibly replace my upper seals; put a new water pump kit in; pressure test it for leaks; assemble the lower unit to mid section, then put oil back into my lower unit. I do have a service manual and follow it as instructed. I feel fortunate I have the ability to ask experienced professionals on this forum questions for clarity. I did an enormous amount of research and found out valuable information from many sources. It was this forum that I found REAL professionals who are generous enough to share their experience to help make mine a good one. I have a few final questions to ask so I feel as confident as I can assembling everything correctly:
* Should I put a light layer of Yama-lube grease over the "O" ring prior to assembly?
* Is it advisable to put YamaLube on the Bearing Race at the rear of the Carrier?
* Should I use a fine crocus cloth to clean the inside of the bore... especially at the spots the carrier rings sit in the bore?
* When I re-install the Shift Shaft, should I simply clean the assembly with brake cleaner then install and verify it's in neutral ?
* My 1998 C115 Service Manual calls for "Hypoid" Lower Unit Oil. It seems as Yamaha no longer produces this oil. Is it because Yamaha now has the ingredient to lubricate the Hypoid Gear Type?
* I have both types....which would you advise to use - or will either work just as efficiently.
Thanks again to all for the valuable help and suggestions I received!

[rodbolt17]

you can use about any abrasive you wish. make sure all is gone before assembly. I use a water proof marine grease on the seals and orings.
use any marine rated GL-4 oil.
simply clean the shift shaft and reassemble in N.

[Soundear]

Thanks rodbolt17 for all of your advice.......This weekend it goes in the water!

[Soundear]

Hi!
You were a tremendous help to me a few weeks ago when U had a lower unit bearing carrier that was hell to free up!
well, with enough heat, I removed it; wirewheel cleaned it, changed the carrier “o” ring; the double seals at the prop shaft ; replaced the upper double drive shaft seals below the water pump and put a brand new water pump assembly in. I made a pressure tester and applied no more than 10lbs PSI, went through the gears and spun the prop in neutral for 10 minutes as pressure held well. I started the motor on dry land with a water feed to the inlet and all looked well. I took the lower screw out to check for water intrusion and a tablespoon of clear water dropped before some “marbled oil” followed. I drained them replaced the oil. I ran it in the harbor; returned and checked the lower unit for water. This time, there was a “milkshake” consistency confirming water intrusion. I thought it might be possible I didn’t tighten the crush washers down enough, so I bought new ones and tightened them well. Just today, I loosened the lower screw to find a “Milkshake” consistency again. I guess I need to take the lower unit off again and pressure test it to find where the water is entering. Was I to replace another seal I missed?

[pstephens46]

Hi!
You were a tremendous help to me a few weeks ago when U had a lower unit bearing carrier that was hell to free up!
well, with enough heat, I removed it; wirewheel cleaned it, changed the carrier “o” ring; the double seals at the prop shaft ; replaced the upper double drive shaft seals below the water pump and put a brand new water pump assembly in. I made a pressure tester and applied no more than 10lbs PSI, went through the gears and spun the prop in neutral for 10 minutes as pressure held well. I started the motor on dry land with a water feed to the inlet and all looked well. I took the lower screw out to check for water intrusion and a tablespoon of clear water dropped before some “marbled oil” followed. I drained them replaced the oil. I ran it in the harbor; returned and checked the lower unit for water. This time, there was a “milkshake” consistency confirming water intrusion. I thought it might be possible I didn’t tighten the crush washers down enough, so I bought new ones and tightened them well. Just today, I loosened the lower screw to find a “Milkshake” consistency again. I guess I need to take the lower unit off again and pressure test it to find where the water is entering. Was I to replace another seal I missed?

What about the shift shaft seal? Give the pressure test another go. Soapy water too.

[rodbolt17]

and that is why after dealing with Yamaha cases for almost 20 yrs I do it the way I do.
do it all at once and be done with it.
experience is a key factor.
just hope the lesson is not very expensive or painful.

years ago when I would show up at the house bleeding my dad would look at me and say"son,if your going to be stupid ya gotta be tough.

this july will mark 30yrs of outboard and stern drive repairsI opened my business account july 20th 1995.
I have factory training on mercury,mercruiser,Volvo,tohatsu,Suzuki,Honda force and Yamaha. for years the bulk of my work was jonny/rudes.

a trick on tempering those J bolts you ask?
oil man.
quenching oil is best but non detergent 30wt works.
once you get done bending heat to cherry red and vertically quench it in oil.
I did pay attention when I was working at GOEX in Cleburne TX. part of my job was heat treating and drawing ovens.