Mercruiser 4.3L trim tab

[Newowner2011]

I have a 91 StarCraft with a 4.3L Mercruiser and a Alpha One outdrive. I took a picture of what I believe is the trim tab which is turned slightly and not straight. See picture. What switch controls that ?On my throttle stick there is button on front for trim, up and down, and on the back side is the tilt, up and down. When I press the down for the trim I hear the engine moving down, when I press the up I think I'm hearing a noise but can't tell if it's a click or what. I hope someone can help.

 

[Bt Doctur]

Re: Mercruiser 4.3L trim tab

the switch you referr to is a ALLEN HEAD BOLT .allen key inserted thru the hole in the top of the cavitation plate.
I cant hear it so you tell me.clicks usually mean a bad solenoid or a corroded connection to the pump itself.

 

[Levinz11]

Re: Mercruiser 4.3L trim tab

That trim tab has no switch. It is offset like that to counteract the torque produced by the spinning prop and hopefully keep the boat going in a straight line.

The trim switch on your remote control raises and lowers the outdrive.

 

[achris]

Re: Mercruiser 4.3L trim tab

The trim tab has 2 purposes. Firstly it's an anode, to protect the aluminium while it's in the water.

Secondly The small fin on it is set to balance the steering bias created by a single spinning propeller. A couple of things about that. The trim tabs' effect varies with the position of the drive (trimming UP and DOWN), and as the trim tab corrodes (as it is designed to do, so don't go painting it. Yes, I have seen it done :facepalm its effect will also decrease (slightly)...

If all you're hearing when you try to raise the drive is a click, as already pointed out, bad solenoid, bad connection. You need to get in with a test light and do some diagnostics... (something a lot of people seem to be allergic to...

)

Chris......

 

[Newowner2011]

Re: Mercruiser 4.3L trim tab

Thanks a lot

 

[Galaxie_Ed]

Re: Mercruiser 4.3L trim tab

Personal experience with my 92 Galaxie California 4.3L Alpha Gen II. My trim tab broke off after getting a tow rope wrapped around the prop. I went to replace with a similar OEM part (material/shape), boat performed horribly. Took extra long to plane out, steering was EXTRA squirrley... Turns out, these kinds of trim tabs are for boats w/o power steering. My fix? Filed the broken tab down to smooth aluminum, replaced and now I can plane out at about 15mph under 3000rpm with just me and the wife onboard... Crazy huh?

 

[achris]

Re: Mercruiser 4.3L trim tab

Personal experience with my 92 Galaxie California 4.3L Alpha Gen II. My trim tab broke off after getting a tow rope wrapped around the prop. I went to replace with a similar OEM part (material/shape), boat performed horribly. Took extra long to plane out, steering was EXTRA squirrley... Turns out, these kinds of trim tabs are for boats w/o power steering. My fix? Filed the broken tab down to smooth aluminum, replaced and now I can plane out at about 15mph under 3000rpm with just me and the wife onboard... Crazy huh?

You have the new style power steering actuator, and yes, you need the anodic plate, not a trim tab... The OP has the old style actuator, and needs the trim tab WITH the fin....

Chris....

 

[Galaxie_Ed]

Re: Mercruiser 4.3L trim tab

You have the new style power steering actuator, and yes, you need the anodic plate, not a trim tab... The OP has the old style actuator, and needs the trim tab WITH the fin....

Chris....

Thx Chris, didn't mean to hijack... just thought I'd chime in...