tkrivitz

We just bought a new (used) boat from a private party. It's a 1992 Cobia San Marino with a 4.3 V6 mercruiser I/O motor. This is our first boat. The first day we took it out everything was fine...but when we left, the bilge pump was still running after the boat was on the trailer. At the time I didn't know that they automatically turn on and off as needed so I disconnected the negative terminal on the battery. I connected the battery back up the next day and it was fine. So we took it out yesterday and my uncle drove it from the boat launch to his pier(about a mile). It took him an hour. He said the trim wouldn't work. After about 5-10 minutes I checked the engine compartment....didn't notice that there were two negative wires--I only reconnected one. So I connected it and the trim worked. Now today we took the boat out and everything worked fine-until we got out to the middle of the lake. I adjusted the trim and noticed that it would only intermittently work. Then, the trim gauge was jumping up and down like crazy and the trim stopped working all together. The gauge would still move around but not a sound when I hit the trim button. There are no blown fuses or anything. The rocker switch for the trim is on the throttle control. I'm wondering if anyone can tell me what probably happened. Is it possible that we damaged something by pushing the trim buttons while the negative was disconnected from the battery??? or is it possible that the switch is damaged? I know there are a lot of possibilities when it comes to electrical problems but I'm hoping someone who maybe had this same problem may know. I didn't have tools with me to take the throttle arm apart and check the switch.
But anyways, What I'm really hoping is that I didn't damage something on the boat---because the trim was stuck all the way down and we had to drive through some really shallow stuff and the prop was in the muck for at least 100 yards---had no choice. So if anyone can please help me out---it'd be much appreciated.
thank you
Tom

Payton

Sounds like a remaining ground wire issue.

MOBILEMERCMAN

The gauge works independent of the trim motor. The gauge is undependable at best. You can hurt it if you didn't hook up both neg leads. Check the solenoids most often they are the problem. You need a volt meter or test light to check the switch and the solenoid functions.

tkrivitz

Do you think we fried the solenoid by activating the switch without the ground being connected? Is it also possible that we fried the switch or something simpler?

ubet28

You might want to back flush the system due to dragging the prop in the mud. If you start to overheat now back flush and check impeller. ONLY IF YOU HAVE OVERHEATING ISUES.

fund razor

Electrical. But doubt it's the switch.
Do you know how to test the trim solenoid, and have you checked it? If not, let us know.
Jim is right.... it's usually the solenoid. Have you checked any and all connectors? (ie: mass connector?) Did you check the two conductor wire that passes through the transom for cracks or frays?

tkrivitz

Ok...An electrician from across the bay at my uncle's house helped me troubleshoot. We checked the switch and the switch is fine all the way up to the relay. Now when we jump the power to one of the bolts on the relay-the relay clicks, but when we press the switch nothing happens. So we jumped the power to the pump and got the trim all the way up-so thank God the pump works and we think it is just the relay. But now I have to take the whole pump out just to get to the relay and remove it and do a few more tests to make sure its the relay. I'm kinda worried about leaking hydraulic fluid everywhere...any ideas? ---also the hydraulic fluid is kind of a a milky yellow color--is that normal? Well-I'm two hours late for work so I better go....but thanks for all the help with everything-. I'll be back on in 7 hours to check again. thanks again
tom

tkrivitz

when we had the trim problem--i didn't even think about checking the other gauges other than that they worked---I think I could've overheated. I ran the motor for a few minutes and it ran a little rough-I think it might be clogged---the boat is still in the water but now that i got the trim up-tomorrow I will put it on the trailor and It will be easier to work on it from there. So how do I back flush the system?
thanks
tom

tkrivitz

You say I CAN hurt if the neg wasn't connected-right? Do you think that is what caused this relay problem?-just hoping I didn't do more damage than I know of.
Well I know the prop is screwed...saw it today-there are some big chunks missing. It's aluminum. Are there any disadvantages to a stainless--other than the price?
Sorry for all the questions-we are new to the boating life
thanks tom

MOBILEMERCMAN

I'm sorry typo You can not hurt the trim motor by not having the ground connected. The power to the switch comes from the dash and that ground works the motor. It will just click but not run. You should not have to pull the motor or open oil lines to change solenoid. The thing you are calling a relay is probably a solenoid. Two big terminals two small. If you need to change one change them both.

The disadvantages of SS are first the money, second more expensive to repair, and if you not going 50 mph there may not be much of a performance advantage. Get used to the boat and attend to its needs first. If you have a tendency to find bottom the SS transmits more stress to your lower unit.