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'[EE] Jet ski -- possible ways for the water to get'
2008\08\15@174126 by Vitaliy

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Does anyone know if there is a way for the water to get inside the engine of
a jet ski, short of rolling it over, and not turning it back upright right
away?

We recently rented a jet ski, and the person last riding it said that toward
the end of the day the engine stalled. He tried restarting it, the jet ski
went for another two minutes or so, and stalled again. He had to be towed
back to shore.

The next morning back at the rental shop, they took out the spark plugs,
which were wet. One of the plugs was completely busted. They were then able
to turn the engine over without any trouble (it spewed out a good amount of
water). According to them, the seat (which covers the engine compartment)
was wet on the inside, they checked the hoses and the only way they see for
the water to get inside the engine, is if the jet ski was rolled over. The
person who rode the jet ski last, assures me he never rolled the jet ski
over (and I was the only other person who rode the jet ski).

The shop wants $2500 to fix the jet ski (the securty deposit was only $400).
Any suggestions?

Vitaliy

2008\08\15@184935 by Carl Denk

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And I am not least familiar with jet skis, but am familiar with engines
in general.

1: Check with the manufacturer.
2: By busted, better description of the sparkplug. Broken sufficient to
allow water in the sparkplug port?
3: Needs to get air for combustion, water could get in that way via air
cleaner, or some port where the air gets in. Exhaust needs a port out,
usually under water, Are there check valves or other method to keep
water out of engine.
4: If 4 cycle engine will have a crankcase breather, another point for
possible water intrusion.
5: Sounds like a lot of money, if that damage happened while you (and
other person) were in possession, corrosion should not be an issue, and
relative few parts are involved, parts costs should be low, labor to
tear down and rebuild to clean could be pricey, but seems much high. Was
there something else broken like crankcase or a piece of tubing to allow
water in. I would want to see with my own eyes what it looks like.
6: How many hours on unit, how many hours before maintenance that might
have prevented situation. Check owners and shop (if they work on them,
they should have one) manuals maintenance schedule and hour meter. There
should be allowance for wear and tear and depreciation.
7: Is unit under warrantee?
8: What does your rental agreement say? Anything more $$ than deposit.
Sounds like they are trying to get you to buy a new engine.
9: Home owners insurance policy might cover, and they will take over
determining what is reasonable.
10: If on credit card, protest charges. If cash, small claims court.
11: Rollover of a Jet Ski doesn't seem that unusual, should be designed
for some of that situation.

Vitaliy wrote:
{Quote hidden}

2008\08\15@192055 by M. Adam Davis

face picon face
If it's a real Jet-Ski(TM) you can get a lot of information here,
including parts list and diagrams: http://www.kawasaki.com - either
way, get the exact manufacturer and model, and hours, and look up the
value of buying one used (rental shops are especially hard on their
products, so it's probably worth less than the used value).

They are asking for a huge amount of money for a jet-ski that probably
cost less than $5k new, so I'd also demand serial number information,
and the maintenance logs.

As far as water getting in, it's a regular internal combustion engine
- the fuel intake and the air intake are the only spots for it to go
in unless the engine was damaged already.  Maybe the gas tank was
leaking?  Still, an engine can tolerate a tiny bit of water mixed with
fuel - to get a lot of water in there would probably go through a
breach or the air intake

Once you get the information regarding the age, model, make, and
details about the damage, shop around and get quotes from other repair
shopw to make sure you aren't getting soaked.

At the end of the day, unless the maintenance logs show poor
maintenance and the typical life for these engines is longer than the
hours on the meter then it doesn't matter how the water got in - you
were the last group to rent it and depending on the contract you
signed you may still be liable.  But getting enough documentation,
quotes, etc will both show them you're serious about preventing them
from taking advantage of you, and will give you leverage to come to a
more equitable agreement.

If they refuse to give you this information, depending on the law and
the contract, you may be able to refuse to pay - but consult a lawyer,
they'll be able to give you real information.

-Adam

On Fri, Aug 15, 2008 at 4:49 PM, Vitaliy <spam_OUTspamTakeThisOuTspammaksimov.org> wrote:
{Quote hidden}

> -

2008\08\15@192806 by Vitaliy

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Carl,

Thanks for your reply. I will try to write a detailed response later, but I
just thought I should mention that it is a 2006 Kawasaki STX-15F, with a
four-stroke engine:

http://www.jetski.com/article.cfm?id=615

Needless to say, I too feel that $2500 for the damage (even if it was our
fault) is excessive.

Vitaliy

2008\08\15@194053 by Carl Denk

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From the link:

Unique semi-dry sump oil system lowers the crankshaft in the engine,
eliminates the need for scavenging pumps, and if the craft is capsized
the oil stays in the sump instead of flooding the crankcase

- Kawasaki's patented oil separator provides fail-safe venting for the
crankcase and prevents oil from flowing into the intake tract if the
craft is capsized


So where did the water enter?? Poor maintenance??



Vitaliy wrote:
{Quote hidden}

2008\08\15@195735 by Vitaliy

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Got an email earlier today from the shop owner:

-->The damaged jetski is a 2006 Kawasaki STX-15F.  As you saw, there was
water in the engine and engine compartment which caused
a valve to break ruining the cylinder head.

A rough estimate to fix the broken cyinder head includes: parts  $3254, 15
hours of labor @ $40 per hour, misc. machine work $250.

The estimate to put in a standard remanufactured engine includes:  Engine
$1795, Gasket Kit $86, Shipping $360.  Total: $2241
These prices include my purchasing discount for the engine and gasket kit.
I am not charging you any labor hours or jetski down time which would total
approximately $500.  The place where I get the remanufactured parts from
said the engine would take 10 days to get.

Please get back with me as soon as you can.  I would like to get the parts
ordered and this ski fixed as soon as possible.
<---

She didn't know exactly where the air intake is on this jet ski. I can ask
their main mechanic guy.

Vitaliy

2008\08\15@210736 by Cedric Chang

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Evidence would suggest that the last person to ride it would be the  
only one who would know if an accident occurred that would allow a  
large quantity of water to enter the engine.  I would say that anyone  
riding it before that could not cause the engine failure of the  
magnitude described.
The other possibility is that poor maintenance or age caused the  
problems.
Based on what you have told us so far, I would suspect the owner is  
trying to get you to pay for an engine that was wearing out and failed  
because of age.  I would not pay for the repairs and I would suggest  
that you be allowed to take the engine to another mechanic for a  
second opinion.  If they won't let you do that then I would refuse to  
pay for repairs.  I would also ask for the number of hours on the  
jetski.
I would also go on a jetski forum and describe what happened and see  
what other folks have to say about what a jetski can tolerate.

The owner is pressuring you for the money because once he has it, the  
discussion ends.  He can repair the jetski without you sending the  
money.  Once you send the money, you will never see it again.

If you can talk to neighboring businesses, ask them how it is to deal  
with him and how he treats his customers.  Generally, I would think an  
honest owner would not be in such a rush to get your money.
cc

{Quote hidden}

> --

2008\08\15@212649 by Carl Denk

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Don't understand how a valve could break from water in the combustion
chamber. The normal air/fuel mixture is compressible since it is a gas.
If a liquid (in this case water, but in other engines could be fuel or
lubricating oil (radial aircraft where it is standard practice to pull
the prop blades by hand backwards to purge cylinders of liquid) gets in
the combustion chamber, and the piston comes up in the compression
stroke with both intake and exhaust valves closed, something has to
give. This almost always happens when the engine is tried to start, and
almost never a running engine, but I guess if water got in a running
engine there would be damage. Basically what happens is the piston comes
up, liquid being not compressible, usually the starter creating power,
with inertia of the flywheel and other components, the following parts
are prime candidates to break: broken/bent crankshaft and/or connecting
rod, broken piston, crankcase or cylinder head. If the valve is open,
the liquid can escape, if the valve is closed, it is supported by the
valve seat in the cylinder head and there are no loads on the valve. I
believe it is more likely the valve failed (is this engine known for
"swallowed valves" ??) from fatigue. If the valve guides are loose
(worn) then as the valve seats on the seat, the stem is allowed to
wobble and the valve head (disc) contacts the seat at different spots
along the perimeter and there is a stress reversal on the stem to head
junction which causes fatigue. When the valve fails, the head comes off
the stem, and may or may not breakup, likely pieces will jamb between
the upcoming piston and cylinder head, usually rattling around there a
bit causing much damage inside the combustion chamber including
battering the spark plug along with breaking heads, crankcases, etc.

As I was writing above, I became more convinced, the valve failed first,
the top of piston and inside of combustion chamber  will  show battering
like the sparkplug.  Have them E-mail pictures of these surfaces (and
you can send them on to me)! The engine has a programmable RPM limiter
that they should have programmed as a rental unit to be conservative
with RPM's so engine speed should not be an issue. The engine if
overspeeded could float valves where the valve doesn't close quick
enough and the piston strikes it bending the valve stem.

I have had an exhaust valve fail on a 320 cu. In. Lycoming aircraft
engine while at 11,500' over Southeastern Georgia (USA) with 4000' thick
clouds below. We made a successful dead engine landing at a small
airport. It took 1/2 hour to figure out what had happened. We were
fortunate that the valve broke up after banging around awhile, with the
crankcase, cylinder, connecting rod and piston intact. The engine was
not contaminated with debris, and we changed the cylinder (head is part
of assembly) and were on our way in 2 days. When we got home we replaced
all the other exhaust valves. With my familiarity of engines and what I
learned, I can say the problem is not yours, and the water came after
the valve failed.  Were there any unusually noises after it stopped
first time.

Vitaliy wrote:
{Quote hidden}

2008\08\15@212822 by Carl Denk

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Go to your local airport and ask the mechanics about swallowed valves
they may even have some pieces laying around.

Vitaliy wrote:
{Quote hidden}

2008\08\15@214913 by Apptech

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> The shop wants $2500 to fix the jet ski (the securty
> deposit was only $400).
> Any suggestions?

This makes excellent commentary on Tomas' recent comments on
the practice of being required to leave an 'open' credit
card slip with some people as security.


       Russell



2008\08\15@222101 by Apptech

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> The person who rode the jet ski last, assures me he never
> rolled the jet ski
> over (and I was the only other person who rode the jet
> ski) ...

You know if you are telling the truth (hopefully :-) ).

I'd ascertain as accurately as I possibly could whether the
other peson is telling the truth. Not knowing how they
relate to you I don't know how sure you can be of this. In a
situation like that I'd be as easy on the consequences for
them as I could be. If I could be certain they were telling
the truth then it would allow me to adopt a different person
with the owners than otherwise.

The stall then run then die scenario is interesting. Did
anyone see the final expiration. Enough water to break a
valve after a while but to allow it to run for several
minutes before doing so seems "interesting". Not perhaps
impossible but questionable, I'd have thought. Unless
perhaps there was more water lurking in the inlet and then
ingested. But, I'd have expected a bent conrod to have been
more likely - or that as well.


   Russell

2008\08\15@222128 by Brent Brown

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I guess one argument is that a Jet Ski is intended to operate in water, if you fall off
while riding it that's considered part of the sport, so if the machine fails mechanically
while you are renting it and not treating it abnormally then it should not be your
responsibility.

That argument suits you more than the renting company I'm sure :-)

I suggest asking around companies that sell/service jet ski's and find out if water
damage to engines in fact common, and under what circumstances. Perhaps even
this specific model has some design quirk that makes it more susceptible in some
way or some commonly occuring fault. A four stroke can drop a valve for other
reasons too, then it breaks things, then water comes in...



2008\08\15@231053 by Jake Anderson

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Vitaliy wrote:
{Quote hidden}

Sounds a bunch like a blown head gasket to me, no need for foul play
there. Had it happen to a friend in a car and when we pulled the plugs
and turned the engine over it sprayed water all over the place. It would
also explain the loss of power the other guy had. (same thing happened
to her, she was leaving a toll booth and just had no "go" and then it
died and wouldn't start.

The engines are more than likely water cooled so that seems like the
easiest (and most common) way of getting water into the cylinder.
I would be surprised if there wasn't a float/flapper valve of some kind
in the air intake to prevent a rolled craft sucking water.

If its still possible check the oil, Its not certain but typically a
blown gasket will put water into the oil which turns it cloudy/milky white.
Although if its just blown then I'd drain the oil and see how much water
comes out. Best not to tell them what you want to check before you do it
or they will just change the oil before you get there.

2008\08\16@064908 by Richard Seriani, Sr.

picon face
Maybe it is past time to take this out of EE and put in OT, where it
belongs.

----- Original Message -----
From: "Vitaliy" <.....spamKILLspamspam@spam@maksimov.org>
To: "Microcontroller discussion list - Public." <piclistspamKILLspammit.edu>
Sent: Friday, August 15, 2008 7:56 PM
Subject: Re: [EE] Jet ski -- possible ways for the water to get in the
engine?


{Quote hidden}

> --

2008\08\16@081835 by Carl Denk

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Should have mentioned last night, the valve assembly can fail also due
to the retainer/keeper holding the spring in place can fail, along with
the possibility of a spring breaking/collapsing allowing the valve to
stay open and getting struck by the piston. Though leaking head gaskets
can cause damage, in this case, I think the valve failing (for a variety
of reasons mentioned) was the first event. This is evident from the fact
of a failed valve and the battered sparkplug. Sure would like to see
pictures of the area.

There is the issue of who can shout the loudest, the rental agency
saying it was upside down, which doesn't hold water in my thinking, and
the failed valve. It will be the renter's burden of proof to show the facts.

Brent Brown wrote:
{Quote hidden}

2008\08\16@093039 by olin piclist

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Vitaliy wrote:
> -->The damaged jetski is a 2006 Kawasaki STX-15F.  As you saw, there
> was water in the engine and engine compartment which caused
> a valve to break ruining the cylinder head.

I know nothing about Jet Skis and have never been on one, but a few things
don't add up here.

First, This being a small water craft, surely thought was given in the
design to what happens if it were to capsize with the engine running.  Given
the many years since these things first became available and the many that
were made, this must be a well known common failure mode if it is one at
all.  At the least I would contact Kawasaki about what happens if a Jet Ski
is rolled with the engine running.  I suspect the symptoms will be different
than those you observed, proving that's not what happened.

Second, a valve breaking doesn't sound like a plausible failure of water
getting into the engine.  A bent crankshaft or bent piston rod would make a
lot more sense.  I suspect some other failure occurred first, probably
related to the cam shaft, timing belt, pushrods, etc.  However that doesn't
explain how the water got into the engine.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

2008\08\16@095316 by olin piclist

face picon face
Olin Lathrop wrote:
> Second, a valve breaking doesn't sound like a plausible failure of
> water getting into the engine.  A bent crankshaft or bent piston rod
> would make a lot more sense.  I suspect some other failure occurred
> first, probably related to the cam shaft, timing belt, pushrods, etc.
> However that doesn't explain how the water got into the engine.

Someone else mentioned a head gasket failure.  That makes a lot of sense to
me too as the first failure, more so than what I listed above.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

2008\08\16@101957 by Carl Denk

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Concur with the thought of other possible causes of valve breaking, but
apparently (from what we have been told) that a valve did break, and
that caused other damage including the broken cylinder head, which
likely is a gapping hole, and not just a small crack, and that is where
the water entered. This is an overhead cam engine so there are no
pushrods, but there could be rockers in there, and one of those could
have siezed with the valve open, but not likely. In that case, the
rocker shaft should show signs of seizing like scoring and galling.
Absence of signs of the crankshaft/connecting rod seizing, damage to
those pieces likely caused by jamming the valve pieces, limiting travel
of the piston upward. A valve failure can cause total engine failure,
where the engine literally explodes becoming an instant basket case (to
be recycled!). Pictures would be worth a 1000 words. :)

Here's a couple of links to swallowed valve:
A B-29 aircraft
books.google.com/books?id=pQVvxiEckYkC&pg=PA75&lpg=PA75&dq=swallowed+valve&source=web&ots=sZV5orItYB&sig=hJHsA8alAQ5mEBkL3rvSoeKaVBA&hl=en&sa=X&oi=book_result&resnum=9&ct=result#PPA52,M1
A small aircraft
http://www.37000feet.com/report/272120
An in depth history of an aircraft valve issue including excellent
engine monitor data
http://www.avweb.com/news/savvyaviator/savvy_aviator_50_lessons_from_a_geriatric_jug_196369-1.html

These are all aircraft which you would expect to be highly reliable, but
there were stories of VW bugs , and others also.

Olin Lathrop wrote:
{Quote hidden}

2008\08\16@112938 by Charles Rogers

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Russell:
Does jet ski repair really belong on the PICList ? ? ?
CR




----- Original Message -----
From: "Apptech" <.....apptechKILLspamspam.....paradise.net.nz>
To: "Microcontroller discussion list - Public." <EraseMEpiclistspam_OUTspamTakeThisOuTmit.edu>
Sent: Friday, August 15, 2008 8:48 PM
Subject: Re: [EE] Jet ski -- possible ways for the water to get in the
engine?


|> The shop wants $2500 to fix the jet ski (the securty
| > deposit was only $400).
| > Any suggestions?
|
| This makes excellent commentary on Tomas' recent comments on
| the practice of being required to leave an 'open' credit
| card slip with some people as security.
|
|
|        Russell

2008\08\16@145701 by Apptech

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> Russell:
> Does jet ski repair really belong on the PICList ? ? ?
> CR

*Some* aspects of the present thread, maybe.
In EE, no.
As I'm sure Bob will opine any day now.
I hadn't noticed it was [EE] tagged.

Hey all - what about moving this to OT?
I'd be interested in knowing the conclusions reached in due
course.



       Russell




2008\08\16@153002 by Vitaliy

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Charles Rogers wrote:
> Does jet ski repair really belong on the PICList ? ? ?

Charles, I paused for a minute before submitting the post, and considered
whether to send it to OT or EE. However, I really needed an expert response
to an engineering question -- therefore, I felt that EE was appropriate.

I'm not trying to repair the jet ski; I simply want to gather engineering
evidence to prove to the rental company, the credit card company, and
possibly in a small claims court (if it comes to that) that the damage done
to the engine was not caused by me or another rider.


I want to thank everyone who responded, your input is truly appreciated. At
this point it seems to me that the most likely explanation for what happened
is a blown head gasket, which is consistent with the facts:

- When I was riding the jet ski, the "Coolant Hot" light came on. Per
instructions, I slowly rode it to the shore and let the engine cool. I
noticed that there was steam coming out of a tube on the right side of the
jet ski (toward the front). I have a feeling this is when the water started
slowly leaking into the engine.

- After the "Coolant Hot" event, it became increasingly difficult to start
the engine. At first, all it took was a brief push of the "Start" button. As
the time went on, it became more and more difficult to get the engine to
start.

- Eventually, enough water got into the engine to cause it to stall.


Jake Anderson described a similar situation when the coolant entered a car
engine through a blown head gasket. Wikipedia has this to say:

"If the gasket fails, a variety of problems can occur, from compression loss
(leading to power reduction, or a rough engine), to exhaust gases being
forced into the cooling system, leading to the engine overheating and
increased engine wear due to the motor oil being mixed with antifreeze.
Coolant can leak into the cylinders, causing the exhaust to issue steam[3]
and the catalytic converter to be damaged. If a very large amount of coolant
does this, hydrolock can occur, causing extensive engine damage. Sometimes,
all that may happen when a head gasket is blown is excessive steam erupting
from the tailpipe; yet the engine may act and drive like normal."

The mechanics checking the engine used the term "hudrolock" to describe the
cause of the damage.


Thanks again for all your responses (and your patience). Feel free to change
the heading to [OT] when replying.

Sincerely,

Vitaliy

P.S. Can someone confirm what the purpose of the tube where the steam was
coming from? I was told by the mechanic that it was from a pump that pumps
the water from the hull.

2008\08\16@154829 by Martin K

face
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I think that's key, I would want to know how much time was on the
engine. Most jet-skis look new because they're all plastic/fiberglass,
but the engine could have hundreds of hours or more. I agree with your
view here. Also be aware that they could lie about the hours on the
engine, etc. If they won't let you inspect the engine then it's a
no-deal in my opinion. You can inspect parts for wear and see how much
stress the engine was under.
-
Martin

Cedric Chang wrote:
{Quote hidden}

2008\08\16@161633 by Apptech

face
flavicon
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>> Does jet ski repair really belong on the PICList ? ? ?

> Charles, I paused for a minute before submitting the post,
> and considered
> whether to send it to OT or EE. However, I really needed
> an expert response
> to an engineering question -- therefore, I felt that EE
> was appropriate.
>
> I'm not trying to repair the jet ski; I simply want to
> gather engineering
> evidence to prove to the rental company, the credit card
> company, and
> possibly in a small claims court (if it comes to that)
> that the damage done
> to the engine was not caused by me or another rider.

The following comment is part of exploring the role and
relationship of the EE/TECH/OT tags (that's my story
anyway). Not the sort of thing I expect to be posting to EE
very often.

I'd have been happy with it on [TECH]. It really never was
EE - although I'm not complaining about it being there (I'll
let Bob do that :-) ) - just noting that it fails the EE
tests (just like my "China Calling" does :-) ). In both
cases I guess we are aiming at the audience we know is there
rather than the subject per se. AFAIK most of the people in
EE are also in TECH, with a few notable exceptions :-).

In the case of the Jet Ski it may have been wiser to move it
out of EE fairly promptly.

There seems to need to be somewhere that members can discuss
things like this. No, I'm not suggesting another tag :-).
Arguably OT is the proper catchall, but in cases like this
where there is a very substantial technical content and good
learning opportunities I think TECH would have been good. I
guess we feel we need to have confidence that the audience
we are addressing is present in the area we post. If I
thought Xiaofan would be interested in my China Calling
meanderings (although in fact I think it unlikely) then
using OT or TECH would have missed him.

So ...

I'd suggest that TECH is probably the best starting point
for something like this. Maybe with a "please don't reply"
note to EE if you feel you really need the extra coverage.
YOMV.


           Russell


2008\08\16@162718 by Walter Banks

picon face


Apptech wrote:

> The stall then run then die scenario is interesting.

Was it running on both cylinders.

I have seen an outboard that bent a con rod with water in the engine.

w..

2008\08\16@170900 by Richard Seriani, Sr.

picon face

----- Original Message -----
From: "Vitaliy" <spamspamspam_OUTmaksimov.org>
To: "Microcontroller discussion list - Public." <@spam@piclistKILLspamspammit.edu>
Sent: Saturday, August 16, 2008 3:29 PM
Subject: Re: [EE] Jet ski -- possible ways for the water to get in the
engine?


> Charles Rogers wrote:
>> Does jet ski repair really belong on the PICList ? ? ?
>
> Charles, I paused for a minute before submitting the post, and considered
> whether to send it to OT or EE. However, I really needed an expert
> response
> to an engineering question -- therefore, I felt that EE was appropriate.
>

Now that's funny!
An EXPERT response to a marine, motosport, or mechanical engineering
question on the PIClist??
By the very nature of this list, it isn't likely too many of those folks
hang out here.

I recall a real estate agent who once suggested the carpets in a home had
been professionally cleaned. Turn out the owner was a professional tech
writer and he had cleaned the carpets. Ergo...


{Quote hidden}

> --

2008\08\16@171746 by Vitaliy

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Apptech wrote:
> I'd have been happy with it on [TECH].

OK, I will definitely keep it in mind for next time. :)

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