F90 2003 4 stroke lower unit will not drop completely out

[Fishtremble]

I am trying to drop the lower unit to replace the water pump but the drive shaft gets stuck about 18 inches out. There is a highly polished area on the drive shaft I guess from the drive shaft seal. After getting stuck I shoved it back in and put the bolts on not knowing how hard I could pull without doing damage. Is corrosion on the shaft getting it stuck, it feels like it is sticking right at the splines. My question is were do I go from here. Should I force it out and if so damage the drive shaft seal? Is it hard to replace this seal?

 

[AGENT 37]

Re: F90 2003 4 stroke lower unit will not drop completely out

Is the rubber pitot line disconnected for the speedometer hook up. Its at the front end of housing.

 

[99yam40]

Re: F90 2003 4 stroke lower unit will not drop completely out

18" is far enough to use a mirror and flash light to look up into the area and see if it is hanging up on a drive shaft bushing located part way down, maybe that is what caused the highly polished area on the drive shaft

 

[mommicked]

Re: F90 2003 4 stroke lower unit will not drop completely out

Ive looked at my service manual and it shows the splines on the top of the driveshaft have a seperation or groove in the bottom 1/3 of the splines.maybe that is whats hanging up.I dont see any seal on the shaft between the waterpump and the top end of the driveshaft so Im wondering why the polished area your describing.try moving it around gently as it hangs up,back and forth as you lift/lower it slightly.

 

[Fishtremble]

Re: F90 2003 4 stroke lower unit will not drop completely out

Yes the speedometer tube is disconnected. The shaft is polished. I found another post on this site title Yam F115 faint squeal or whistle, which by the way my 90 has done, and said it was caused by the drive shaft seal and to correct it spray corrosion x on the drive shaft and referred to it as the drive shaft seal. I have looked at a lot of schematics for this section and can't find it. Would have loved to shine a light up and take a look but my hands were full of lower unit and after I shoved it back in and told my assistant, wife, to quickly had me a bolt her reply was " what's a bolt ". Anyways for now I went by a sprayed the drive shaft with corrosion X to let it soak a few days.

 

[jeffersondodson561]

Re: F90 2003 4 stroke lower unit will not drop completely out

There is a highly polished area on the drive shaft I guess from the drive shaft seal.

I think you have knocked out that bearing, the highly polished area is where the bearing rides on the shaft. If I remember the 75-115's utilize the the driveshaft to drive the oil pump. Bad news is, if this is the case, once you get the L/U off the Pwrhead is going to have to come off to install the new bearing.

 

[Fishtremble]

Re: F90 2003 4 stroke lower unit will not drop completely out

The polished area is not splinned but does look like it was in a bearing and in secco it does mention that the drive shaft splines actually seat into the oil pump not the crank shaft?

 

[jeffersondodson561]

Re: F90 2003 4 stroke lower unit will not drop completely out

Right, the splined area will be atop of the driveshaft kinda seperated by a valley. Hard to describe this morning only 1 cup o joe so far.

 

[BaileysBoat]

Re: F90 2003 4 stroke lower unit will not drop completely out

The drive shaft bushing is just that, a bushing and not supporting anything. The shiny area is where it contacts the drivehshaft. Normal

http://www.boats.net/parts/search/Yamaha/Outboard/2003/F90TLRB/UPPER CASING/parts.html

If the lower unit came down 18' it has to be free of the power head. The splines must be hanging up on the bushing. Thats all it can be. Give it a good tug and it will come out. Try turning the shaft as you do so.

 

[Fishtremble]

Re: F90 2003 4 stroke lower unit will not drop completely out

Thanks. I'll give it another try this weekend.

 

[Bamaman1]

Re: F90 2003 4 stroke lower unit will not drop completely out

Sometimes they can also be a bear to reinstall. I usually make sure the throttle control and the lower unit are both in neutral. Press the lower unit up into place while someone pushes the throttle control into Forward. It should slide right in.

 

[mommicked]

Re: F90 2003 4 stroke lower unit will not drop completely out

Fishtremble.I also have a 2003 F90 carbed engine(3 yrs) You can PM me if you want to share info.I'm not sure ive got the correct service manual. It says F100 on the cover and some parts of my motor are not shown.copyright 1998.