Prop trim and gauge problem
 

I have just had the bellows replaced on my 2006 SX18 with a Mercruiser Alpha one 3.00lt engine. I have had so many problems with the company doing the service I don't know where to start. However, I have now discovered that the trim is not working properly. I noticed it sounded different but also found the gauge wasn't showing the correct levels. The engineer said he could adjust it which he did. I then found that I couldn't raise the trim above half from the throttle but I could by using the stern control. I know I could raise it higher previously because I had to be careful not to raise it too high whilst being operated. The next time I took it out the gauge was going much higher than the trim was actually moving. Someone has suggested that the gauge may be dirty but I think that there is something more wrong with it and it's supposed to have just been serviced. Can anyone help?:(

Re: Prop trim and gauge problem
 

These are a bit tricky. The "trim sending unit" allows the "trim switch" to only operate the trim to a safe level that won't cause damage. Since you were able to over trim and cuase cavitation, I suspect it wasn't adjusted correctly before it was ever worked on. The "trailer switch" should raise the trim all the way. The gauge should show the entire trim level, meaning, if adjusted properly, the "trim switch" will only operate to about half way up the gauge.
These can come out of adjustment, and contacts can become corroded at the sending unit. Sounds like yours is fully operational, but fine tuning the limit of the sending unit is in question. Hope this helps.

Re: Prop trim and gauge problem
 

Thanks for your help. It sounds like it was never installed properly before delivery but now they have changed the bellows and reinstalled it, it;s correctly stopping it half way from the drivers control. My problem is now to find out why the gauge needle goes much higher than the actual trim is adjusted to. Is it easy to get to where the sensor is without lifting out the water?

Re: Prop trim and gauge problem
 

No, you really need it pulled from the water. The sending unit and limit switch are on each side of the gimbal housing. They are just below the water level, and look like round plastic covers with 4 screws and 2 adjustment screws.

Sounds like it may still be out of adjustment if reading high (which could also limit you from trimming to a preferred level). I'll have to find where I've seen how to measure and adjust it and post it here. It's not hard to do, but I fear introducing water/corrosion anytime I keep opening the cover.

Re: Prop trim and gauge problem
 

Have a look at the "MercStuff.com?" site for a detailed explanation (with pics!) on how to adjust the trim unit.

Re: Prop trim and gauge problem
 

That's where it was!! Thanks Mikey... I was looking all over the place.

Re: Prop trim and gauge problem
 

Thank you very much for your help.
The engineer decided to install a new switch (having lifted it out the water and failed to adjust it). He actually cut off the old switch and installed the new one using water proof joints in the wires otherwise it would have been a very expensive job to remove everything and fit the full wiring. Even now the gauge is still not showing fully down, it's infuriating. I'm sick of getting ripped off by mechanics. e.g. This was an authorised mercruiser mechanic who argued that there wasn't an anode inside the propeller shaft! I had to show him my manual to prove it and made him take the propeller off to find out.
I really appreciate all your help. Cheers

Re: Prop trim and gauge problem
 

Thought I would tag along on this post instead of creating another one... My trim gauge hasn't worked so I was following the steps on mercstuff.com. The first step tells you to loosen the port side (trim limit switch) and then turn it till you get roughly 6 1/2" out on the lift ram. I have tried turning the port side switch fully counterclockwise and fully clockwise and get no change. My rams are at 10" on either setting. So I am assuming that switch is bad. I did pull the contact out and it was pretty clean with no water and light grease. What do you think? And if that is bad, I guess I should go ahead and change the starboard side as well huh?

P.S. Just had a thought...I was using my trim switch on the swim platform and without the key in the ignition. Would that cause this?

Re: Prop trim and gauge problem
 

Most of us just live with a non-functioning trim gauge because to fix it right requires you to remove the outdrive (the wires pass thru the outdrive bellows) and replace the switch & possibly the control box on the inside of the transom. Its one of those things that if you have a reason to remove the outdrive then its a good time to fix this problem.

Re: Prop trim and gauge problem
 

Thanks for the reply. Guess I will just wait till I have to pull the outdrive then.