Trying to change the impeller on my 1991 T9.9

[Smaterchew1]

Just bought a 15ft boat with a T9.9ELHP out board. Not peeing water so I figured an impeller change was due. I know that you first have to back off the locking nut on the shifter linkage and then unscrew the top hex nut from the bottom rod before you can drop the lower unit. My problem is the locking nut broke loose just fine, but I can't get the top hex nut to come loose. The whole rod is wanting to twist when I try to unscrew it. Its not frozen to the bottom shift rod, but appears to be frozen to the top rod. I'm afraid if I put to much pressure on it, I'll break the upper shift rod. There also appears no way of putting pliers to the upper shift rod either. I've soaked it in 10W40 and will try it again tomorrow. But does anybody have an idea how to break that upper hex head nut loose??? Thanks in advnance for your help...

[rodbolt17]

sometimes, on well maintained rigs, it simply wont.
it snaps off the upper pin.
then the powerhead gets removed to fix that.

its also why Yamaha says to remove the gearcase every 100 hrs OR every year.

try heating it with a torch,if that doesn't work it gets snapped off.

[Smaterchew1]

Poorly designed....love yamaha's but why build a link connection that you really can't get to. If I could just get to the shift rod above the hex nut then i could hold it enough to break it loose. As it sits, all I do is torque the rod...and I really don't want to go through the trouble of replacing the stupid thing. But, if I do, can someone recommend a link that will help walk me through the replacement of it?

[99yam40]

Rod already told you the power-head will have to come off if the pin gets broke,
Not sure what kind of link you think will help you.

Yamaha service manual for that motor will be a help

[rodbolt17]

not a poor design.
poor planning.

ya see them japs ALSO printed a maint schedule and expected americans might read and heed.
they were oh so wrong.
most americans dog it till its dead and whine.
maint can be a pain, I mean why replace an impeller that is working?
so 11 yrs go by and it finally gives up.

now you get to find what minerals in the water and dissimilar metals do.

some years back I cut the driveshaft and removed the stub from the crank on an F225.
motor was only 1 1/2 years old with 500 hrs.

gear case had never been off.
cost almost 1000 dollars to do that water pump.
price of the pump stayed the same.

Yamaha says inspect the impellor every 200 hrs OR yearly whichever occurs FIRST.

and that's when you grease splines bolts and linkages.

[bajakeith]

X 2

I'll Second rodbolt...EDIT..WD 40 is crap !! Try Aero kroil !!