I have a couple of '84 150's. One I rebuilt in 2000 and
the other has had no major work. These are basically
the same as the 200 with a different carb.

They both run like tops. I baby them and inspect regularly.
The biggest problem is rust. These were manuf. before the Sal****er
Series and Im afraid the power heads are going to outlast
the Tilt/Trims, Shift rod, Steering arm, lower unit, etc..

Pull the props and inspect the large keeper (thrust?) ring
just inside the lower unit. This ring has a tendancy to
corrode in-place and crack the lower unit. I had to weld
one of my lower units' oil case shut.

I can find no mention of proper compression in any Yamaha manual
for these puppies other than they should all be within a few psi and
mine are. The rebuild being slightly higher of course.

I would guess they are worth somewhere in the neighborhood
of $1000 - $1500 ea.

Oh yea...

Do loosen and and re-tighten the lower unit bolts occasionally.

Enjoy!

db~that reminds me, Its about time to start thinking about de-winterizing
and
spring inspection.





"Mark" Boatbasin@optonline(remove this).net wrote in message
...
Very reliable engines, the 150 and 200's seem to last. The most common
problem on this engine is first that the shift rod rusts badly at a spot
just below the powerhead where it becomes exposed below the cowling. It
is
a rod about 1/4 in.diameter. If you see it heavily rusted then plan on
replacing it soon. Not hard to fix, but up to $1k per engine depending on
rusted bolts etc. The second problem is that the water pumps are so
reliable on these engines that many people go years without replacing
them,
if ever. The pump might still be good, but the lower unit bolts seize and
could cost the whole lower. Make sure you can drop the lowers or readily
tell if if it has been done in the last few years. Other than that, if
the
compression is within parameters, the engines have a very good tarck
record.

"Jim and Becky" wrote in message
...
I'm pondering (always will be) a boat with a pair of 1988 Yamaha 200's.
The seller says they have 1025 hours on them.
Assume they weren't used commercially and have been well taken care of.
What is the life expectancy (total hours) of these?
Lets say we call them obsolete when they drop more than 15% of their
original output. I'm in an area I know nothing about but some power loss
might be expected due to worn pistons, etc.
All I can think of is one motor dying about the first of July and
getting
the boat back in the water around mid September.
I remember reading 10,000 hours for an inboard gas, maybe twice that for
an
inboard diesel?