Mercruiser Stern Drive Power Tilt Troubleshooting
 

Hi Everyone-

I'm trying help a friend out figuring out why one of his power units
won't retract on his I/O. It seems to be stuck in the up position. I
can hear the pump running (both directions) when he hits the switch.
We've tried jumping on the unit while hitting the switch at the same
time. In fact the other unit was also stuck and we got it working
again by this method. When the switch is hit in the up position, it
looks like it travels up slightly. I'm thinking either a stuck check
valve or cylinder? Does anyone know the best method to diagnose? The
boat is a 83 or 84 Wellcraft Nova with twin 350 small blocks. From
what I've gathered it has Alpha I outdrives. Any input would be
appreciated.

Mercruiser Stern Drive Power Tilt Troubleshooting
 

You can disconnect the lines at the pump to see if it is the pump or the
cylinders. It's messy. Just because the pump motor runs does not mean it
is pumping. You can also diosconnect the cylinders at the ends over the
prop and see that the outdrive can be moved up and down freely. That will
also lket you see if maybe just one cylinder is stuck.

The early ones only had one line to each cylinder. The later ones had lines
going to both ends of the cylinders. The later style works better.

"rustyjames" wrote in message
oups.com...
Hi Everyone-

I'm trying help a friend out figuring out why one of his power units
won't retract on his I/O. It seems to be stuck in the up position. I
can hear the pump running (both directions) when he hits the switch.
We've tried jumping on the unit while hitting the switch at the same
time. In fact the other unit was also stuck and we got it working
again by this method. When the switch is hit in the up position, it
looks like it travels up slightly. I'm thinking either a stuck check
valve or cylinder? Does anyone know the best method to diagnose? The
boat is a 83 or 84 Wellcraft Nova with twin 350 small blocks. From
what I've gathered it has Alpha I outdrives. Any input would be
appreciated.

Mercruiser Stern Drive Power Tilt Troubleshooting
 

The piston is seized in the stuck cylinder from lack of lube. Don't
continue to try to free it with the pump. A stalled pump will burn up.
You can free up the cylinder by putting it in a press, and applying a
ton or two of pressure to push the piston back down. Stand clear of the
bottom port when doing so. Once it moves in, install and bleed it. The
trim pump will be able to operate it now. Run the drive up and down
several times, but do not overheat the pump. Fixed a stuck cylinder on
Cruis'n Rulz! like this.
JR

rustyjames wrote:
Hi Everyone-

I'm trying help a friend out figuring out why one of his power units
won't retract on his I/O. It seems to be stuck in the up position. I
can hear the pump running (both directions) when he hits the switch.
We've tried jumping on the unit while hitting the switch at the same
time. In fact the other unit was also stuck and we got it working
again by this method. When the switch is hit in the up position, it
looks like it travels up slightly. I'm thinking either a stuck check
valve or cylinder? Does anyone know the best method to diagnose? The
boat is a 83 or 84 Wellcraft Nova with twin 350 small blocks. From
what I've gathered it has Alpha I outdrives. Any input would be
appreciated.



--
--------------------------------------------------------------
Home Page: http://www.seanet.com/~jasonrnorth

Mercruiser Stern Drive Power Tilt Troubleshooting
 

On Aug 20, 4:40 pm, "jamesgangnc" wrote:
You can disconnect the lines at the pump to see if it is the pump or the
cylinders. It's messy. Just because the pump motor runs does not mean it
is pumping. You can also diosconnect the cylinders at the ends over the
prop and see that the outdrive can be moved up and down freely. That will
also lket you see if maybe just one cylinder is stuck.

The early ones only had one line to each cylinder. The later ones had lines
going to both ends of the cylinders. The later style works better.


I should have mentioned that we disconnected the cylinders and the
drive moves freely. The cylinders have two lines. Most of the lines
to the cylinders are pretty snug and we were afraid of breaking them.
We managed to get one cracked but I thought the flow appeared
inadequate. The fluid looked fine. Thanks for the info and I think
going back and cracking the line at the pump is a good idea to see if
a/the cylinder(s) is/are stuck.

Mercruiser Stern Drive Power Tilt Troubleshooting
 

On Aug 20, 5:30 pm, JR North wrote:
The piston is seized in the stuck cylinder from lack of lube. Don't
continue to try to free it with the pump. A stalled pump will burn up.
You can free up the cylinder by putting it in a press, and applying a
ton or two of pressure to push the piston back down. Stand clear of the
bottom port when doing so. Once it moves in, install and bleed it. The
trim pump will be able to operate it now. Run the drive up and down
several times, but do not overheat the pump. Fixed a stuck cylinder on
Cruis'n Rulz! like this.
JR

Thanks for the reply. You're probably right about a stuck piston or
two and the press idea sounds like a plan if we can't get them to move
while still attached to the outdrive.