"I posted a similar note a wee
"I posted a similar note a week ago. While picking up some parts, I asked my local marine mechanic. he told me that this is a tough problem to diagnose and solve. It could be the cylinders, T/T unit or both. Hard to find and expensive to fix. He suggested the exact support that Bob references (which I already have). He said that it could be a small speck of dirt (or equiv) that's stuck in a check valve.
One note...he shared that, while it goes against his better sense (his words), he said that he's had some luck with holding the T/T button down for a second or two once the drive reaches the max height. We're programmed (at least I am) to release the button as soon as the T/T pump starts to strain. He seems to think that the extra second seems to "pack in" a bit more fluid and may help. I haven't tried it yet, so I'm not confirming or recommending it."