I just bought a 240 Sundancer with Bravo III I/O. The throttle control has a power trim switch on the side. My trim guage appears not to be working so that I can't tell the status of the outdrive. The boat has a swim platform so that I can't see the outrive from the stern. The mechanic at the marina said it could be expensive to fix. Is this the same control that tilts the outdrive all the way up for palcing it on a trailer? Can I inadvertently tilt the unit so that the props come out of the water while I am cruising? Do you use this trim to adjust the bow angle while planning? Shouldn't I be tilting it up if approaching shallow water?
You have a trim limit switch that should prevent the lower unit from continuing on to tilt mode if the engine is running and you do not have a separate tilt switch. TEST it on on land first with the muffs to verify, or better yet...repair it. Remember to keep RPMs under 1500 for the muffs, but also to protect the universal joint. A good way to frag a I/O universal is high RPMs with a high driveline angle (trimmed out). As always, more experienced boat pros, correct me if I'm wrong.
ok, I'll chime in here.
You have one switch for your tilt and trim. To make sure we have our terms straight, tilt is what you use to raise the lower unit in and out of the water. Very rarely will you use the motor above the trim position. Trim means small movement in the angle of the lower unit AFTER the lower unit is in the water and running. You should be able to hear the unit lowering or raising the lower unit, and it will make a different pitch depending on "tilting" or "trimming".
On a personal note, I have found trim gauges to be of limited use. While underway, the boat will respond to trim very nicely. If the boat is porpoising, trim the motor down or lower. This will lower the bow. In turns and hole shot, trim down for more control and less bow rise. You would trim up to get your bow up while running in relatively flat water, to allow the bow of the boat out of the water for faster speed and more efficiency. I would use a trim gauge for none of these activities.
You need to experiment a little, and it will come clear to you.
That all being said, fix the gauge. I hate to see things on a boat that don't work properly. It reflects bad on the boat and on the skipper....