New Volvo SX has more cavitation/higher RPMs

[fjd0413@lycos.com]

I recently had to fully replace my Volvo SX outdrive and prop due to an incident. After the change with the exact new SX outdrive and the same 19" pitch prop,
I get allot of cavitation and racing RPMs when trimming out the slightest bit. In addition, my trim gauge bounces, which never happened before. Any ideas?
Thanks!

 

[volvopaul]

I recently had to fully replace my Volvo SX outdrive and prop due to an incident. After the change with the exact new SX outdrive and the same 19" pitch prop,
I get allot of cavitation and racing RPMs when trimming out the slightest bit. In addition, my trim gauge bounces, which never happened before. Any ideas?
Thanks!

Sounds like air in the trim rams, move then up and down fully a few times and check the oil level.

 

[fjd0413@lycos.com]

Thanks for the response. I checked the fluid level and it looked good. Would you expect this to be a problem even if the hydraulics we never opened for the repair?
I used to be able to trim this a few degrees, but now, I'm barely trimming it and having the problem. Not sure why the gauge is bouncing since this repair as well (never touched as far as I know).

 

[volvopaul]

Thanks for the response. I checked the fluid level and it looked good. Would you expect this to be a problem even if the hydraulics we never opened for the repair?
I used to be able to trim this a few degrees, but now, I'm barely trimming it and having the problem. Not sure why the gauge is bouncing since this repair as well (never touched as far as I know).

The sender can be on the trim pin or on an arm right side of drive near gimball head, I'd check this is secured to the shield and not loose, I'd also check the hinge pins for tightness.

 

[GrahamHR]

The SX trim sender is on the stardoard side; the actuator fits into the pivot pin..

 

[volvopaul]

The SX trim sender is on the stardoard side; the actuator fits into the pivot pin..

Not on all models it doesn't, some have a separate potentiometer that has a small arm that's sprung loaded which pushes against the gimball head as it lifts up and down.

 

[GrahamHR]

Not on all models it doesn't, some have a separate potentiometer that has a small arm that's sprung loaded which pushes against the gimball head as it lifts up and down.

Really, fitted by Volvo Penta on a SX/ SX-MHP transom shield assembly ( or on a Volvo Penta/ OMC "joint venture" shield) ? I've never seen such a device on one or on parts drawings. Those devices I referred to are not the most reliable, seemed like when they designed them they forgot to take into account that they would be used in an aqueous environment !

 

[fjd0413@lycos.com]

Guys, this blog is great! The information is very helpful. Would still be very interested in any opinions as to how the sensor/gauge were affected by hitting the outdrive.

 

[ari]

I recently had to fully replace my Volvo SX outdrive and prop due to an incident. After the change with the exact new SX outdrive and the same 19" pitch prop,
I get allot of cavitation and racing RPMs when trimming out the slightest bit. In addition, my trim gauge bounces, which never happened before. Any ideas?
Thanks!

Are you relying on the gauge to tell you how much trim you have? Sounds like the gauge has a problem, so maybe you think you're trimming up a few degrees but in reality the leg is much higher than it should be due to the gauge being inaccurate - hence the cavitation.

Maybe try ignoring the gauge, trim it all the way down till you can hear it's down (rather than relying on what the gauge is reading), then trim up slightly as you normally would, again ignoring what the gauge tells you.

If that resolves it then it's just the gauge sensor to sort out.