5.7L Volvo Penta with Trim Issuies , fine on the trailer in the water not so much

[trailerman4]

I have a 2005 21ft Ebbtide with a 5.7l Volvo SX Penta outdrive, 133 hours all fresh water,... problem I have , is that when the boat is in the water, when you take off & start trimming the trim up to get the boat out of the water, it will in a matter of a minute or two, fall back down, but on the trailer when trimmed all the way up, it stays there ??? I have checked for leaks, everything, new to the forum so any suggestions would be much appreciated

 

[Sparkinator]

No Title

Have you checked the o-rings in your manual release valve.(the valve that you screw out to manually lift or lower the drive) If that isn't seating (not screwed in all the way or bad oring), the drive won't stay up. I may stay up on the trailer, but when running in forward, more pressure is being applied than just gravity and it may not hold the drive up then.

It could be bypassing elsewhere in the system, but that's where I would check first.

 

[trailerman4]

Thanks,... I ve check ( but not really sure what Im looking for ) I don't see a release valve,.. It's a Volvo Penta # 3860879 SAE J-1171 where would this set screw be located,... Thanks for all the help