Venting, these engines are a nightmare!

I have twin 100hp 4-stroke Yamahas. They have about 900 hours on them. So
far this season I have developed major problems with both. I'm begininng to
question the longevity of the 4-stroke yamaha. I'd guess that there are not
too many of these engines with 900 hours on them. I'd be willing to wager
that these engines are flawed. I think it is the same block as the 90hp so
the problems might also be on these motors.

The problems a

1) the oil pump has about a 900 hour lifespan before it begins to leak down
the driveshaft and make a mess of everything. This has now happened on BOTH
my engines. Seems more then a coincidence.

2) one of the engines leaks water and exhuast into the engine oil. This one
I am still diagnosing but I think it is the plate(gasket0 between the
powerhead and the upper unit.

For both these problems the powerhead needs to come off. The only saving
grace is that the powerhead is fairly easily removed and reinstalled.

Anybody else having these problems? Anybody else have either 90, 100, or
115hp Yamahas? If so how many hours? I'd keep a close watch on these
issues if you are getting up there in hours.

"mijoy" wrote in message
...
Venting, these engines are a nightmare!

I have twin 100hp 4-stroke Yamahas. They have about 900 hours on them.
So
far this season I have developed major problems with both. I'm begininng
to
question the longevity of the 4-stroke yamaha. I'd guess that there are
not
too many of these engines with 900 hours on them. I'd be willing to wager
that these engines are flawed. I think it is the same block as the 90hp
so
the problems might also be on these motors.

The problems a

1) the oil pump has about a 900 hour lifespan before it begins to leak
down
the driveshaft and make a mess of everything. This has now happened on
BOTH
my engines. Seems more then a coincidence.

2) one of the engines leaks water and exhuast into the engine oil. This
one
I am still diagnosing but I think it is the plate(gasket0 between the
powerhead and the upper unit.

For both these problems the powerhead needs to come off. The only saving
grace is that the powerhead is fairly easily removed and reinstalled.

Anybody else having these problems? Anybody else have either 90, 100, or
115hp Yamahas? If so how many hours? I'd keep a close watch on these
issues if you are getting up there in hours.


I feel your pain. I had a Nissan/Datsun truck that had only 160,000 miles
on it before things started breaking down. What a piece of crap that was.
Sounds like you got a lemon.

If you are insinuating that 900 hours is a lot, you must be one of those 50
hours a year people.

To compare it to your car example:
at 50 miles an hour, it would take 2000 hours to travel 100,000 miles. Most
people would think that they should gt 100,000 miles out of a car before
major engine repairs.

My Yamahas, using the above analogy, is at about 48,000 miles.



"NOYB" wrote in message
...

"mijoy" wrote in message
...
Venting, these engines are a nightmare!

I have twin 100hp 4-stroke Yamahas. They have about 900 hours on them.
So
far this season I have developed major problems with both. I'm
begininng
to
question the longevity of the 4-stroke yamaha. I'd guess that there are
not
too many of these engines with 900 hours on them. I'd be willing to
wager
that these engines are flawed. I think it is the same block as the 90hp
so
the problems might also be on these motors.

The problems a

1) the oil pump has about a 900 hour lifespan before it begins to leak
down
the driveshaft and make a mess of everything. This has now happened on
BOTH
my engines. Seems more then a coincidence.

2) one of the engines leaks water and exhuast into the engine oil. This
one
I am still diagnosing but I think it is the plate(gasket0 between the
powerhead and the upper unit.

For both these problems the powerhead needs to come off. The only
saving
grace is that the powerhead is fairly easily removed and reinstalled.

Anybody else having these problems? Anybody else have either 90, 100,
or
115hp Yamahas? If so how many hours? I'd keep a close watch on these
issues if you are getting up there in hours.


I feel your pain. I had a Nissan/Datsun truck that had only 160,000 miles
on it before things started breaking down. What a piece of crap that was.
Sounds like you got a lemon.

"mijoy" wrote in message
...
If you are insinuating that 900 hours is a lot, you must be one of those
50
hours a year people.

Nope. I put 200+ hours on each of two different boats each year. That's
about 400 hours of boating each year. 900 hours is lower than what one
would hope to expect, but it is still a lot of hours. Most guides down here
run 180-200 charters/year. If their motors run 6-8 hours each trip, then
they're putting on 1000-1500 hours per year...which is why most of them
trade motors every one to one and a half years.




To compare it to your car example:
at 50 miles an hour, it would take 2000 hours to travel 100,000 miles.
Most
people would think that they should gt 100,000 miles out of a car before
major engine repairs.

My Yamahas, using the above analogy, is at about 48,000 miles.


You can't compare the two that way. Outboards run in a sal****er
environment, most often running at 75% or more of their redline.

You can't compare the two that way. Outboards run in a sal****er
environment, most often running at 75% or more of their redline

Yeah I know. But to put it in perspective, most cars if well maintained die
of other reasons then blown engines well after 100,000 miles.
Maybe I am fooling myself but I do have hopes of 1500 before engine internal
problems. We'll see.


"NOYB" wrote in message
...

"mijoy" wrote in message
...
If you are insinuating that 900 hours is a lot, you must be one of those
50
hours a year people.

Nope. I put 200+ hours on each of two different boats each year. That's
about 400 hours of boating each year. 900 hours is lower than what one
would hope to expect, but it is still a lot of hours. Most guides down
here
run 180-200 charters/year. If their motors run 6-8 hours each trip, then
they're putting on 1000-1500 hours per year...which is why most of them
trade motors every one to one and a half years.




To compare it to your car example:
at 50 miles an hour, it would take 2000 hours to travel 100,000 miles.
Most
people would think that they should gt 100,000 miles out of a car before
major engine repairs.

My Yamahas, using the above analogy, is at about 48,000 miles.


You can't compare the two that way. Outboards run in a sal****er
environment, most often running at 75% or more of their redline.

"mijoy" wrote in message
...
You can't compare the two that way. Outboards run in a sal****er
environment, most often running at 75% or more of their redline

Yeah I know. But to put it in perspective, most cars if well maintained
die
of other reasons then blown engines well after 100,000 miles.
Maybe I am fooling myself but I do have hopes of 1500 before engine
internal
problems. We'll see.


I hope you're right. I just repowered with a Suzuki 250 four-stroke. What
a terrific engine. The motor that it replaced was a two-stroke Yamaha 250
with 870 hours on it. Of course, that Yammie was a 1991. I bought it last
October with 705 hours on it, and it blew the top of the powerhead off.

On Sunday 01 August 2004 6:18 pm in rec.boats mijoy wrote:

I have twin 100hp 4-stroke Yamahas. They have about 900 hours on them.
So
far this season I have developed major problems with both. I'm begininng
to
question the longevity of the 4-stroke yamaha. I'd guess that there are
not
too many of these engines with 900 hours on them. I'd be willing to wager
that these engines are flawed. I think it is the same block as the 90hp
so the problems might also be on these motors.

Manufacturers work on the average utilisation of a leisure boat being 100
hours per year. Outboards are designed to deliver maximum power at minimum
weight, which is not the best formula for longevity.

If you want maximum life under heavy uasage you should be using inboard
diesels rated for continuous duty. Take a look at the CAT website where
they rate their engines according to the expected duty cycle.
Typically an engine rated at 600 HP leisure use is derated to around 350 HP
continuous duty.


--
My real address is crn (at) netunix (dot) com
WARNING all messages containing attachments or html will be silently
deleted. Send only plain text.

WRONG, an automotive engine doesn't turn 5200 rpms for hours on end. At 50mph
in a car a 4 cyl engine is turning an average of 2600-2800 rpm. So if you want
to further use this analogy calculate 900 hours at 100 mph or 90,000 miles.

Dennis


To compare it to your car example:
at 50 miles an hour, it would take 2000 hours to travel 100,000 miles. Most
people would think that they should gt 100,000 miles out of a car before
major engine repairs.

Yeah probably true. But do you think the translation is that direct? You
think a 3 year old engine (assuming 300 hours a year) is the equivilent to
an old man?

My next engine is a diesal!



"Esourcedesigns" wrote in message
...
WRONG, an automotive engine doesn't turn 5200 rpms for hours on end. At
50mph
in a car a 4 cyl engine is turning an average of 2600-2800 rpm. So if you
want
to further use this analogy calculate 900 hours at 100 mph or 90,000
miles.

Dennis


To compare it to your car example:
at 50 miles an hour, it would take 2000 hours to travel 100,000 miles.
Most
people would think that they should gt 100,000 miles out of a car before
major engine repairs.

On Sun, 01 Aug 2004 16:44:41 -0400, mijoy wrote:

If you are insinuating that 900 hours is a lot, you must be one of those 50
hours a year people.


I was thinking that. If 900hrs is a lot for an outboard, I'm glad I have
a (diesel) inboard! The last one had 4000hrs on it, and was still pretty
good (I replaced it mainly because it was underpowered). I was told gas
inboards should last 2500hrs or so between overhauls. 900hrs? Barely
broken in!

Lloyd Sumpter
"Far Cove" Catalina 36