I did my 1000 hour on my F70 Yamaha Monday and Tuesday. There was no
real drama, just a lot of "check/replace". I threw a water pump kit at
it and I was surprised that the kit comes with the shaft seals. It
turned out I needed them because here was trace water in the foot and
a drop of oil coming out of the intake screen. I also noticed Yamaha
has a better way because the bearing surface on the shaft seems to be
replaceable and the design seems to avoid getting sand on the seal (a
Merc problem on the "big foot") I ended up putting a "speedie sleeve"
in my Merc 60 BF because the shaft was scored.
I also threw a set of plugs at it but I am not sure why. They looked
brand new.

http://gfretwell.com/ftp/1078%20hour%20plug%20F70.jpg

Surprisingly the do look pretty good for those hrs...

On Thu, 22 Sep 2016 12:56:43 -0400, wrote:

I did my 1000 hour on my F70 Yamaha Monday and Tuesday. There was no
real drama, just a lot of "check/replace". I threw a water pump kit at
it and I was surprised that the kit comes with the shaft seals. It
turned out I needed them because here was trace water in the foot and
a drop of oil coming out of the intake screen. I also noticed Yamaha
has a better way because the bearing surface on the shaft seems to be
replaceable and the design seems to avoid getting sand on the seal (a
Merc problem on the "big foot") I ended up putting a "speedie sleeve"
in my Merc 60 BF because the shaft was scored.
I also threw a set of plugs at it but I am not sure why. They looked
brand new.

http://gfretwell.com/ftp/1078%20hour%20plug%20F70.jpg

They don't look bad for 1000hrs. Maybe you did all that 'cause Yamaha said so?

On Thu, 22 Sep 2016 10:09:29 -0700 (PDT), Tim
wrote:

Surprisingly the do look pretty good for those hrs...

These EFI engines are pretty easy on plugs. Some cars can go 100,000
miles on a set of plugs. That is 3000 hours or so.
This is 1500 hours on my 60 EFI (same motor Don has)
http://gfretwell.com/ftp/1500%20hour%20plug.jpg
It is the same basic block that Yamaha uses but you see they use a
longer plug and you see the difference on the threads. It ends up
deeper in the combustion chamber. I suppose things like that and a
little better intake manifold gets it the extra few horsepower that
lets them call the same engine a 70 instead of 60. It is supposed to
bench out around 67hp. The 60 was 63 or so.
It made virtually zero difference on my boat using the same prop when
I swapped.

On Thu, 22 Sep 2016 15:34:11 -0400, Poquito Loco
wrote:

On Thu, 22 Sep 2016 12:56:43 -0400, wrote:

I did my 1000 hour on my F70 Yamaha Monday and Tuesday. There was no
real drama, just a lot of "check/replace". I threw a water pump kit at
it and I was surprised that the kit comes with the shaft seals. It
turned out I needed them because here was trace water in the foot and
a drop of oil coming out of the intake screen. I also noticed Yamaha
has a better way because the bearing surface on the shaft seems to be
replaceable and the design seems to avoid getting sand on the seal (a
Merc problem on the "big foot") I ended up putting a "speedie sleeve"
in my Merc 60 BF because the shaft was scored.
I also threw a set of plugs at it but I am not sure why. They looked
brand new.

http://gfretwell.com/ftp/1078%20hour%20plug%20F70.jpg

They don't look bad for 1000hrs. Maybe you did all that 'cause Yamaha said so?

I just did the plugs because I had a slow start thing but I think the
cap was just loose on the plug.
The rest is just a lot of inspect/replace. I did figure out you should
do the cylinder zincs every 500 or so. The rest last a lot longer. The
cylinder zincs run in 140 degree water instead of ambient. Makes a big
difference.

On Thu, 22 Sep 2016 10:09:29 -0700 (PDT), Tim
wrote:

Surprisingly the do look pretty good for those hrs...

"These EFI engines are pretty easy on plugs. Some cars can go 100,000
miles on a set of plugs. That is 3000 hours or so.
This is 1500 hours on my 60 EFI (same motor Don has)
http://gfretwell.com/ftp/1500%20hour%20plug.jpg
It is the same basic block that Yamaha uses but you see they use a
longer plug and you see the difference on the threads. It ends up
deeper in the combustion chamber. I suppose things like that and a
little better intake manifold gets it the extra few horsepower that
lets them call the same engine a 70 instead of 60. It is supposed to
bench out around 67hp. The 60 was 63 or so.
It made virtually zero difference on my boat using the same prop when
I swapped."


Better change that "has" to had.
I was getting up to 75 hours on the Big Foot 60 so it was time to change to the MerCruiser 3.0.
Getting lots of use from it...30 hours so far with about a month left to add to that. ;-)