How to change lower bolt on yamaha F80

[peterv6i]

Hi, on my Yamaha F80 (2003 year) I would like to chagne bolt.
The problem is that original bolt is completly rusty.
Other problem is that I don't know if I can extract old bolt from it seat without disassembly engine from upper part (I don't know if there is enaugh space to extract old bolt and insert new one)..

thank you for any info

[rodbolt17]

to access that bolt.
remove powerhead and lower unit.
remove the lower cowling.
withdraw the speedo tube.
unbolt the bonding wire.
remove both upper and lower mount nuts.
remove the entire midsection.

now we can access the bolts for replacement.

to do that remove the mount covers and extract the mounts.

[peterv6i]

Thank you for info!

[exeter27]

Rodbolt is right. I did this on my F60 because the bolt totally failed on the unit I picked up. The bolts aren't cheap (about $20 per when I bought them).

Label everything and take lots of pictures. It's not a hard job - and once the powerhead has been removed, it's pretty easy going after that. It also gives you a chance to do a thorough cleaning.

I managed to put mine back together and everything worked out fine. Good luck.

[almetelo]

The problem is that original bolt is completly rusty.]

Are you sure you want to have all that work/spend time/Money to replace a bolt that is rusty? ( if is ONLY because of rust)

On my F100 that bolts are also rusty on the tips (shoudn´t IMO but they are)

Seems to be a common problem at least on this models and I don´t consider replace them.

My guess is if you'll replace them in a few years will be rusty again.

Thats just me...

[TownsendsFJR1300]

Are you sure you want to have all that work/spend time/Money to replace a bolt that is rusty? ( if is ONLY because of rust)

On my F100 that bolts are also rusty on the tips (shoudn´t IMO but they are)

Seems to be a common problem at least on this models and I don´t consider replace them.

My guess is if you'll replace them in a few years will be rusty again.

Thats just me...

+100^^.... Unless the head of the bolt is rusted really bad (say beyond 50%), its got years left in it.

Just my 2 cts...

A good winter project I guess!

[99yam40]

It is always good to get it replaced before you have nothing to put a wrench on

[exeter27]

I think I mis-read your schematic. You are pointing to the bolt on the mounts down below on the lower unit. I changed the upper mounting bolts - that run under the engine (block).

I'm not sure if you need to remove the block to replace the lower bolts. Sorry about the mis-read. Get a service manual - and that will remove all doubt!

[peterv6i]

I'm not sure if you need to remove the block to replace the lower bolts. Sorry about the mis-read. Get a service manual - and that will remove all doubt!

Yes this are lower bolts.. I will make some photo just to see how the bolts are look like..

[bajakeith]

Bad m/m bolts

I started using other bolts than OEM yammy bolts as that they SUCK !!

[peterv6i]

This is my lower bolt

[TownsendsFJR1300]

Once you lean on that nut, it'll likely bust loose/off. Easy enough to get to with a cut off wheel if need be.

[99yam40]

If it was mine I would clean up the rust the best I could and treat it to slow the rust down.
keep it greased up and hope it does not fail while you still have the motor in running condition.
Taking it apart like Rodbolt said to replace those bolts could lead to a lot of other broken bolts etc.

[TownsendsFJR1300]

If it was mine I would clean up the rust the best I could and treat it to slow the rust down.
keep it greased up and hope it does not fail while you still have the motor in running condition.
Taking it apart like Rodbolt said to replace those bolts could lead to a lot of other broken bolts etc.

The outside looks real bad, what counts is did water(especially salt water) penetrate inside?

If not, he'd probably be fine, however over the years, water likely did get in there and corrode (and you know Yamaha didn't put any corrosion product in there), especially since they used crap bolts... Maybe not as much corrosion inside, but you don't know.....

IMO, I'd address it now, you don't want the engine breaking loose while in the water, worse case scenario, loose the engine altogether..

[peterv6i]

At the inside the bolt is ok. it look like new.. the rust is only on the side before the nut..
What is the procedure to replace that bolt?