my first boat, power tilt trim questions

Hello everyone I'm new to the forum,I recently purchased my first boat its a 16' glastron bowrider with a 1975 70hp Johnson in it. It also has power tilt/...trim?? Here's my question I had the motor tilted upward in the water prop was about 12" under water wanted to spray a rooster tail ( just rebuilt my carbs) anyways when I did this my motor dropped down under acceleration seems like it dropped down almost emidiatley when throttling forward. I assume it dropped all the way down. But tilt picks the motor up and down just fine also under throttle to lift the motor to trim it out the motor won't lift up unless I'm going about 10mph or less is this the classic signs of bad seals that it won't hold the motor under power? Also in reverse while accelerating the motor lifts up. Any suggestions?? Couldn't see any oil near the pump because the guy I got the boat from painted the motor black any input would help being this is my first boat.thanks for the help

Re: my first boat, power tilt trim questions

Newbie here also but I think there's a lever to lock your outboard down so it won't flip up in reverse. Not sure if that will help the problem with tilt tho..

Re: my first boat, power tilt trim questions

The tilt piston is not strong enough to hold the motor up at speed the motor will actually push the piston back in the system was designed this way on purpose. The trim pistons will hold the outboard in the position selected until the tilt piston starts to lift the outboard increasing the power on the outboard will over power the tilt piston forcing the outboard back down on to the trim pistons. If your outboard only has power tilt then you have to use the manual trim pin to set the optimal trim for the outboard.

Re: my first boat, power tilt trim questions

so is it possible that I'm not putting my motor all the way down for this to happen then? How do I tell if I have trim? I have and up and down switch on my throttle lever when I put my motor in the water should I let it 100% down? Maybe this would cure my issue then. Because I just let the motor down so it appears vertical from my seat. Hmmm... possible operator error???

Re: my first boat, power tilt trim questions

It has two smaller cylinders on either side of the tilt cylinder in in the middle. Does that mean it has trim? 1 long cylinder and 2 smaller cylinders looks like an older set up.I can take a picture and post also if it will help diagnose this issue

Re: my first boat, power tilt trim questions

that means you have tilt and trim. it will only trim so high while under load and then it will go no further. As stated above the tilt piston wont hold it under load. not all boats make a rooster tail without a jack plate.

Re: my first boat, power tilt trim questions

Thanks for the help!! I'll be sure to have my motor all the way down and try er out thanks again!