If I decide to buy a used outboard, is a dyno run at full power the best way
of assuring myself the engine is OK?

If I wanted a seller to have a dyno run done on a candidate engine, I assume
I would be obligated to pay the associated costs. Is this normally the
case? I would like to set it up to where I wouldn't pay costs if the engine
failed the dyno run.

Is it something reasonable to ask of a seller, assuming I say I'll pay the
cost unless it fails?

"RB" wrote in message
...
If I decide to buy a used outboard, is a dyno run at full power the best
way
of assuring myself the engine is OK?

It would tell you that the engine is currently working reasonably well. It
wouldn't give you any assurance of how long it would continue to work. The
engine could still have cooling problems, leaks, etc.

If I wanted a seller to have a dyno run done on a candidate engine, I
assume
I would be obligated to pay the associated costs. Is this normally the
case? I would like to set it up to where I wouldn't pay costs if the
engine
failed the dyno run.

I have no idea where you would have a dyno test done on an outboard, or how
much it would cost. If I was selling a motor, and a buyer said that he
wanted a dyno run, I would not agree unless the buyer was covering all the
costs associated with the test including transportation of the motor. I
certainly wouldn't agree to paying the cost in the event of a failure unless
it was clearly defined what "fail" means.

If it is a 200 HP motor, and according to the dyno it delivered 199 Hp, is
that "failing"?

This situation isn't much different than getting a survey on a boat. In
this case, the buyer usually pays the cost of the survey. If he doesn't
like the results of the survey for any reason he can abort the sale, but he
still has to pay for the survey.

Rod

A DYNO test is usually for troubleshooting unique problems. If I were in
your position, I would ask for a compression test--a long max power run in
the lake and 20 minutes at fast cruise power--proof that the overtemp
sensors worked--a throttle-burst test or 2 as in lifting a skier--and a
gearcase pressure-test. If you want more than that--buy a new motor.

Thanks for the thoughts and idea. A number of used o/bs for sale are on
stands, off the boats they were on. So, and "in the water" trial isn't
feasible.

A number of dealers do have dynos, and will do a dyno run for you for some
setup fee.

I just thought maybe a dyno run under load, at full throttle, would be about
as good as I can do in assessing the o/b condition.

I've been told that the o/bs, in general, lose maybe 1-2% of their power per
year due to normal wear. If this is so, and is factored in, then the power
attained at full throttle, the duration of the test run, and the load
imposed are all good gauges of the overall condition.

Some sellers, of course, won't be bothered with letting me do a dyno run on
their o/b.

My brother purchased a used Nissan 8 hp (1996) for $800 last summer. The
seller said to give him $600 up front and the last $200 in 30 days. The
seller stated he'd cover up to $200 in repairs for 30 days.
My brother put the engine through it's paces on no less than six
outings. The engine seemed fine. Six weeks after he had the engine, the
water pump went bad. Cost about $150 to repair it. So now he's got $950
in a seven year old motor. For less than 1/2 that price he could have a
new motor. I'm certain other problems are on the way. Only time will
tell if it was worth buying used. In this case, I'd bet not.


RB wrote:
If I decide to buy a used outboard, is a dyno run at full power the best way
of assuring myself the engine is OK?

If I wanted a seller to have a dyno run done on a candidate engine, I assume
I would be obligated to pay the associated costs. Is this normally the
case? I would like to set it up to where I wouldn't pay costs if the engine
failed the dyno run.

Is it something reasonable to ask of a seller, assuming I say I'll pay the
cost unless it fails?

Something in your post doesn't make sense: "For less than 1/2 that
price he could have a new motor. "

Not for a boat motor! If you meant twice that price, then that
might be in the ballpark for a motor of that size.

As far as the water pump is concerned, that is considered a normal
wear item to be changed out yearly or every other year, depending on
usage. Had your brother been interested in doing the work himself,
had the time, and is mechanically inclined, he could do this normal
maintenance himself in a couple of hours at a parts cost of, I'd
guess, between $20 and $40. A 'water pump' in a boat motor isn't
like a water pump in a car. It's a rubber impeller and is
considered a normal wear item. If your brother is feeling ripped
off about this motor as a result of this, he should probably
seriously consider selling it. Not being sarcastic here. Boating
is fun, but no one said it was cheap! Well, sailors perhaps. :^)
If he encounters a real problem with the motor, that's when it can
and usually does get expensive.

-JimL


user wrote:
My brother purchased a used Nissan 8 hp (1996) for $800 last summer. The
seller said to give him $600 up front and the last $200 in 30 days. The
seller stated he'd cover up to $200 in repairs for 30 days.
My brother put the engine through it's paces on no less than six
outings. The engine seemed fine. Six weeks after he had the engine, the
water pump went bad. Cost about $150 to repair it. So now he's got $950
in a seven year old motor. For less than 1/2 that price he could have a
new motor. I'm certain other problems are on the way. Only time will
tell if it was worth buying used. In this case, I'd bet not.

On Tue, 18 Nov 2003 21:24:25 -0600, "RB"
wrote:


I've been told that the o/bs, in general, lose maybe 1-2% of their power per
year due to normal wear. If this is so, and is factored in, then the power
attained at full throttle, the duration of the test run, and the load
imposed are all good gauges of the overall condition.

Some sellers, of course, won't be bothered with letting me do a dyno run on
their o/b.

If you can't do a seatrial, I think a dyno test is a great idea. I
also think, no matter the results, you bear the cost.

I recently bought a Yamaha 130. I new there was a problem, but unless
it was under load, all appeared fine. I took it to a Yam dealer and
until he put it on the dyno, it appeared to run fine. On the dyno, it
showed it was only putting out about 70%. I had the carbs cleaned and
then it was put back on the dyno. The dealer reported the engine was
putting out a full 130 hp. My on the water test sure made a
difference.

bb

"user" wrote in message
...


Six weeks after he had the engine, the
water pump went bad.

Water pumps wear out, normal wear and tear. Some people replace them every
year, others wait till they fail. If the impeller had never been replaced,
then seven years on the impeller is certainly pushing it. It would certainly
be wise to ask the seller when the impeller was changed last.

They will also self destruct in a matter of seconds if you run the motor
dry. Even a brand new impeller on a brand new motor won't tolerate being
run dry.

Cost about $150 to repair it.

An impeller repair kit, which would include the impeller, gaskets and seals,
should cost around $50. The rest would have been labor. It isn't hard to
do, shouldn't require any special tools, so he could have saved himself $100
if he had replaced it himself.

So now he's got $950
in a seven year old motor. For less than 1/2 that price he could have a
new motor.

Did you mean twice?

I'm certain other problems are on the way. Only time will
tell if it was worth buying used. In this case, I'd bet not.

Buying new always has its advantages, but depending on how this motor was
used and cared for it could still have a lot of life left in it.

Rod