Maximum safe 'Up' trim on stern drive

randys58

My Rinker 232 Captiva CC has a broken 'up' trim button (and gauge) which forces me to raise motor using 'trailer' button. Manual says 'extreme damage' can result from running over 1500 rpm with drive up too much. But this is my first season with the boat and I won't be able to have 'up' switch repaired until next fall.

 

Question is: how much 'up' trim is safe. I've been running boat with full 'down' trim but entering and leaving shallow water would be easier if I could 'up' trim. Any rough guide on how far 'up' is safe?

 

Randy

Capt_Steve

@randys58 ... First you need to check your trim gauge and make sure when the drive is going down and stops it just hits the full down mark on the gauge. That way you know the gauge is reading properly and as soon as you start going up the needle will start moving up. With this being said you can run the trim up to half way with no problems even when you are on plane. If you go up any higher while on plane the prop will start slipping and you will be slowing down. When you are off plane even if you are over 1500 rpms you could be up ¾ on the gauge as long as you are 2000 rpms or less.

Dream_Inn

I'll add to Steve's comments.  I sometimes have to go out the "back way" during high tide cause I can't get under a fixed bridge.  The water is a bit shallow, so I put the drives up almost all the way without using the trailer button (no, I don't have one).  As Steve said, run it up with your trim all the way to see where it is (without the engine running, maybe on the trailer).  Now, you will begin looseing your steering the more you put it up & you always need to watch and make sure your engine temp does not go up - means you are not drawing water & that is a huge issue immediately.

I would not run it at half way on plane, it is a bit rough on the prop trying push all that weight at that speed and more than likely you will have some cavitation.  Also, as Steve said, make sure gauge is correct (a lot of them don't always work well).

Lifes Good

Gosh guys lifting the drives above half makes me nervous at any rpm! That's a lot of torque and pressure on the ujoint. I am a bit more conservative and never go over 1/4. To much money is involved by pushing the envolope and my depth alarm is set at 10 feet.

LG

Black_Diamond

U-joints have interesting dynamics as you increase the angle of operation. They need some angle to make the bearings roll, but more angle increases the stress on the parts and you do not get smooth power rotation out of it. In a perfect world, they like ~3-7 degrees of angular offset. Watch how many lifted trucks drop driveshafts (few correct the angles).

bat32

I know if I want to lift my drive over half way I have to further depress the switch to get it up past that point.  The dealer told me never to operate past an idle above half other wise you will do damage.  That being said, I know if my trim is not set correctly on plane I get a vibration through the boat.  The sweet spot seems to be between an 1/8 to a 1/4 up on plane for me.  I'm also like Dream I have to trim all the way up sometimes to get out of the channel but this is at low speeds. 

TikiHut2

Bat, Your dealer took his warning straight from the manual and it's good advice, as everyone else has shared.