Yamaha T8 Lower Unit Removal

[downriggeral]

I have a friend that I am helping replace the seals in his lower unit. I have removed the four nuts and shift shaft connection. The problem is the lower unit is stuck on and will not budge. Any suggestions short of dynomite? HELP! bandmyheadbandmyhead

[Bduck]

Not familiar with T8's but was wondering if a hidden bolt under a push-on cap coming from opposite direction?

[SuperD]

Click on the year and model of T-8 he has, then select "Lower Unit Casing". It will show a schematic of all the working parts so that you get all the bolts.

http://www.boats.net/parts/search/Yamaha/Outboard/parts.html

[downriggeral]

Thanks for the input guys.

I have been to the parts break-down and actually purchased the water pump and lower unit seals there. There are four studs that go through an extension housing for the long shaft. They have nuts and washers. In the short shaft there are just four bolts. I think because of the salt water use the studs have corroded to the housing welding it together. I was able to remove one stud and it had a lot of corrosion on it. P-oil will not penetrate because the studs fit quite tight through the lower unit housing. I am from an aviation mechanic background and HATE to brutalize tender aluminum housings. Sure would have been nice if the engineers had designed a slot for a wedge! The only other thought would be to grind one at the front and back with a cut off wheel.......sure hate to do it though.

[dragonfly]

when you go back coat everything with the nickel antiseize including the surfaces, next time it will come apart a lot easier the copper works but the nickel just works better. here's a site with a step by step on the water pump change out that might help. http://www.huntfishnw.com/index.php?topic=1845.0
one thing that works on the corrosion is an acid called alumabrite it will dissolve the oxidized aluminum but not the good we use it to clean the headache racks on the semi's and our aluminum trailers, but care has to be taken. dfly

[downriggeral]

Thanks all,

My friend is off to the Yamaha dealer to have his motor brutilized by them. It will be interesting to see what they come up with.

[SuperD]

Update? Did he manage to get it apart without destroying anything?

[downriggeral]

Well................He got nervous and didn't want to watch if I brutilized it so he took it to the Yamaha dealer. They told him they would have to use an acetylene torch to get enough heat and most likely would lose the extension housing above the lower unit. That's exactly what happened but they did get it apart. At least the drive shaft wasn't stuck in the crankshaft of the motor. Said they needed the studs...$25 each from Yamaha (stainless 6mmx4"); OUCH. Total cost $675 for the job and my friend already had a hundred bucks worth of parts he ordered. Moral of the story, pull those lower units and service them every two or three years in fresh water and more often in salt. Good anti-seize as recommended is a life saver. Guess it was cheaper than a new motor. Moral of the story: SALT KILLS, bring money!

[HookedOnKokanee]

Everyone knows the definition of the word boat:

B break

O out

A another

T thousand

Same thing happened to my 15 hp mercury, a few years back ... any ways you are now ready for the up coming season!

[autorick]

Last winter i tore into mine and fought it. I was able to get it apart with zero damage, which surprised me, and i used the silver antisieze on everything when i put it all back together. Mine is saltwater free.

[downriggeral]

Final update on the T8 saga - well the "dealership" got the unit off. They had to rent an acetylene torch for a hundred bucks ( really) and heat the extension housing to get the lower unit off. They said it would cost more to clean up the stainless studs than to replace them at $25 each....really? Then they were going to replace the extension housing because they got it hot...well they couldn't get one for several months from Yamaha so I asked my friend how bad it was really. Seems clean up and re-paint fixed it for a mere 1/2 hour labor @$53. They put the new seals and water pump in, provided by my friend, and he got out of there for only $650! No body ever said boat fishing was going to be cheap........