Strange, but here's the story.

I have a 40 hp '97 Yamaha The tilt trim works GREAT when the motor is at
rest, ...up and down all day long. It works GREAT when the key is on and
the boat is in the water ...up and down all day long...It holds its raised
position if I leave the motor raised up all night long!!!

but.....

When the boat is under way, even moving very slowly, it will go down, but
it won't go up . It tries. I can hear and see the hydraulic shaft trying to
raise the engine. It doesn't seem to have enough power, even at very low
speeds???

My mechanic, ( by phone, from 1200 miles away ) suggested I try

1. bleeding the system ( I did..to no avail) and
2. check the "bypass".... (I don't know where the "bypass " is).... to be
certain that someone didn't leave it loose.. He couldn't sufficiently
describe it's location over the phone. I did find an Allen wrench ( metric)
fitting in the cylinder area, but it was very tight. The motor is mounted
on a manual jack plate, so it is possible that I cannot see the bypass
without pulling the engine from the JP. ??? Anyone know where the d%%#$#
thing is???

I don't want to bring it to an unfamiliar dealer here ( Lake Geneva,
Wisconsin) since I know they are all backed up and I don't want to be
with-out my boat for three weeks right now.

Any ideas? If I had to guess, I'd think that the voltage to the t/t motor
is too low... when under way. I checked (looked at ) the connections, and
they look great inside of the engine. I did NOT take any voltage
measurements, but will if some one thinks that might tell me something
useful.

Any help or advice appreciated. Thanks RichG

-- manager, Carolina Skiff Owners Group on MSN
http://groups.msn.com/CarolinaSkiffOwners

It is possible the "up" solenoid (relay) is flaky. You could swap it with
"down".
The bypass is just a screw that releases pressure when you are going to open
the hydralic system. They should show you where it is in your owner's manual
and that may be on the net.
I rebuilt my Merc unit several years ago and it is pretty complicated. Lots of
little rubber parts that they sell for huge bucks. If you wrinkle an O ring or
cup you will have to start over.

From what I can see inside of the engine, I think the Up and Down solenoids
are all one molded piece, positioned under the engine cover. I've traced the
wiring to it, anyhow. Even if one of the solenoids were bad, that still
doesn't explain the 100% reliable UP and DOWN when at rest, but no UP
performance when running. thanks anyhow.

--
RichG manager, Carolina Skiff Owners Group on MSN
http://groups.msn.com/CarolinaSkiffOwners

Sounds like your battery is weak. Have you tried another battery? Swap one
from your car for a quick test.

"RichG" wrote in message
. ..
From what I can see inside of the engine, I think the Up and Down
solenoids
are all one molded piece, positioned under the engine cover. I've traced
the
wiring to it, anyhow. Even if one of the solenoids were bad, that still
doesn't explain the 100% reliable UP and DOWN when at rest, but no UP
performance when running. thanks anyhow.

--
RichG manager, Carolina Skiff Owners Group on MSN
http://groups.msn.com/CarolinaSkiffOwners

The problem is the pump is not producing enough pressure to raise the engine
under load.
Probably not something you can repair where you are.
Either the pump is bad or the o-ring in the piston is not holding pressure.

Try this - raise the engine up about 1/2 way and then run the engine - does
the engine drop under load. If it does - you have a seal leak in the
piston. If not - it is a pump problem.
Verify you have the right amount of fluid in the system (not sure on a
Yamaha how to check this). Otherwise - you have a pump rebuild/replace
ahead of you.
--
Tony
my boats at http://t.thomas.home.mchsi.com

"RichG" wrote in message
m...
Strange, but here's the story.

I have a 40 hp '97 Yamaha The tilt trim works GREAT when the motor is at
rest, ...up and down all day long. It works GREAT when the key is on and
the boat is in the water ...up and down all day long...It holds its raised
position if I leave the motor raised up all night long!!!

but.....

When the boat is under way, even moving very slowly, it will go down, but
it won't go up . It tries. I can hear and see the hydraulic shaft trying
to
raise the engine. It doesn't seem to have enough power, even at very low
speeds???

My mechanic, ( by phone, from 1200 miles away ) suggested I try

1. bleeding the system ( I did..to no avail) and
2. check the "bypass".... (I don't know where the "bypass " is).... to be
certain that someone didn't leave it loose.. He couldn't sufficiently
describe it's location over the phone. I did find an Allen wrench (
metric)
fitting in the cylinder area, but it was very tight. The motor is mounted
on a manual jack plate, so it is possible that I cannot see the bypass
without pulling the engine from the JP. ??? Anyone know where the d%%#$#
thing is???

I don't want to bring it to an unfamiliar dealer here ( Lake Geneva,
Wisconsin) since I know they are all backed up and I don't want to be
with-out my boat for three weeks right now.

Any ideas? If I had to guess, I'd think that the voltage to the t/t
motor
is too low... when under way. I checked (looked at ) the connections, and
they look great inside of the engine. I did NOT take any voltage
measurements, but will if some one thinks that might tell me something
useful.

Any help or advice appreciated. Thanks RichG

-- manager, Carolina Skiff Owners Group on MSN
http://groups.msn.com/CarolinaSkiffOwners

Well, on one boating group on the net, one guy postured that some of the '97
Yamahas only came with TILT, but not with TRIM???? and my observations of
the motor's action was consistent with a TILT only rig.

I stopped into a Yamaha dealer today, and they confirmed, that, for my
serial number series, they could only find TILT repair kits, but not TRIM
repair kits. I looked at the engine ( again) and see only ONE piston shaft
showing. I guess that is the LIFTING piston, and if I had TRIM, I would have
TWO piston shafts?? Sounds like I don't have a problem, just an engine that
I bought for a very good price without a feature that I don't need very
often.

I've added Smart Tabs to the 16 ft Carolina Skiff and she runs flat out
great. Thanks for all of your help. Any comments till appreciated, though...
--
RichG manager, Carolina Skiff Owners Group on MSN
http://groups.msn.com/CarolinaSkiffOwners



"Tony Thomas" wrote in message
news:mnOxc.73506$Ly.11791@attbi_s01...
The problem is the pump is not producing enough pressure to raise the
engine
under load.
Probably not something you can repair where you are.
Either the pump is bad or the o-ring in the piston is not holding
pressure.

Try this - raise the engine up about 1/2 way and then run the engine -
does
the engine drop under load. If it does - you have a seal leak in the
piston. If not - it is a pump problem.
Verify you have the right amount of fluid in the system (not sure on a
Yamaha how to check this). Otherwise - you have a pump rebuild/replace
ahead of you.
--
Tony
my boats at http://t.thomas.home.mchsi.com

"RichG" wrote in message
m...
Strange, but here's the story.

I have a 40 hp '97 Yamaha The tilt trim works GREAT when the motor is
at
rest, ...up and down all day long. It works GREAT when the key is on
and
the boat is in the water ...up and down all day long...It holds its
raised
position if I leave the motor raised up all night long!!!

but.....

When the boat is under way, even moving very slowly, it will go down,
but
it won't go up . It tries. I can hear and see the hydraulic shaft trying
to
raise the engine. It doesn't seem to have enough power, even at very low
speeds???

My mechanic, ( by phone, from 1200 miles away ) suggested I try

1. bleeding the system ( I did..to no avail) and
2. check the "bypass".... (I don't know where the "bypass " is).... to
be
certain that someone didn't leave it loose.. He couldn't sufficiently
describe it's location over the phone. I did find an Allen wrench (
metric)
fitting in the cylinder area, but it was very tight. The motor is
mounted
on a manual jack plate, so it is possible that I cannot see the bypass
without pulling the engine from the JP. ??? Anyone know where the d%%#$#
thing is???

I don't want to bring it to an unfamiliar dealer here ( Lake Geneva,
Wisconsin) since I know they are all backed up and I don't want to be
with-out my boat for three weeks right now.

Any ideas? If I had to guess, I'd think that the voltage to the t/t
motor
is too low... when under way. I checked (looked at ) the connections,
and
they look great inside of the engine. I did NOT take any voltage
measurements, but will if some one thinks that might tell me something
useful.

Any help or advice appreciated. Thanks RichG

-- manager, Carolina Skiff Owners Group on MSN
http://groups.msn.com/CarolinaSkiffOwners