How far can I safely trim out drive at WOT?

[chaparral442]

I have a 19ft bowrider, with 4.3 Merc sterndrive. How far can I safely trim out the outdrive at 3/4 or WOT ?

I have heard that if you trim to far out or up that it can damage the coupler or other components

 

[QC]

Re: How far can I safely trim out drive at WOT?

It is the U-joints you have to worry about most, but you can trim out all of the way to the top of your "trim" limit at any power setting. I run fully trimmed out at 3/4 to WOT a lot. I have done so with a Bravo and an Alpha with no problems whatsoever. That's how you get the best top speed and the best efficiency for higher throttle settings . . .

According to Merc you should not exceed 1200 RPM above the trim limit. That is what most people are referring to. Many here say "never" run above trim limit. I am sure it may shorten life some, but I'd rather have 17 hours less U-joint life than get out a paddle or replace a prop . . .

 

[chaparral442]

Re: How far can I safely trim out drive at WOT?

It is the U-joints you have to worry about most, but you can trim out all of the way to the top of your "trim" limit at any power setting. I run fully trimmed out at 3/4 to WOT a lot. I have done so with a Bravo and an Alpha with no problems whatsoever. That's how you get the best top speed and the best efficiency for higher throttle settings . . .

explain trim limit- how can I tell when I am at that point?

 

[QC]

Re: How far can I safely trim out drive at WOT?

Does your control have two switches? One that is in the grip and another that says "Trailer" on it? Or does your up trim have two click levels? In either case the drive should stop going up with the grip mounted trim switch with a separate "Trailer" switch or the first "click" on the other type. To raise it higher you need to go to the "Trailer" button or the second "click". If this makes sense the top of the "Trim" limit is the highest the drive will go up without using the second level or "Trailer" button. Sorry for all of the repetitive stuff, but I want to be clear.

 

[chaparral442]

Re: How far can I safely trim out drive at WOT?

Does your control have two switches? One that is in the grip and another that says "Trailer" on it? Or does your up trim have two click levels? In either case the drive should stop going up with the grip mounted trim switch with a seperate "Trailer" switch or the first "click" on the other type. To raise it higher you need to go to the "Trailer" button or the second "click". If this makes sense the top of the "Trim" limit is the highest the drive will go up withoput using the second level or "Trailer" button. Sorry for all of the repetetive stuff, but I want to be clear.

It is a 2006 Mercruiser sterndrive- single button - it does not indicate where trailer setting is- a simple guage with a large horizontal mark, two marks above and two below

 

[INJUN]

Re: How far can I safely trim out drive at WOT?

It should have 2 different sounds. When raising the outdrive, the first sound will be lower and the outdrive will be rising slow. Then it gets to a point when the sound changes to a higher sound and the outdrive picks up speed as if it changed gears. The point at which the sound changed is where you inter the "trailer" mode.

 

[Maclin]

Re: How far can I safely trim out drive at WOT?

I think your boat would start porpoising before it could get to a trim up level that would damage anything internally. You will know when you are too far up while cruising.

 

[QC]

Re: How far can I safely trim out drive at WOT?

First, Injun, that is incorrect with a Merc. OBs yes, I/Os no.

Second, Maclin, if he has a heavy bow and/or a low X-dimension, It may not porpoise or lose bite before it is too high.

And Third, Chapdude, go back to your control and tell us what model number it is and double check the up switch. I'll bet it has two "levels". You should be able to click the button lightly and then push harder and get a second click . . . All of them have trim limit unless the handle is bad, non-Merc and incorrect, or it is a Merc one and it has failed . . . Do not depend on the gauge until you know where the trim limit is as the gauge can be adjusted just like the trim limit, so it is possible that halfway is perfect on your gauge and 1/3 is the top of trim on mine . . . Usually about a third of the way though on the boats that I have driven. Including Volvos.

 

[a70eliminator]

Re: How far can I safely trim out drive at WOT?

My OMC i/o has the trim button on the throttle lever, there is no trim limit switch or trailer nothing but in and out, I'll trim out more and more if I go a little too far the prop blows out and RPM's spike then I'll trim back in as little and off I go, don't know if I'm doing it right but with a non working trim guage and no trim limit what do you do?

 

[Gary H NC]

Re: How far can I safely trim out drive at WOT?

My OMC i/o has the trim button on the throttle lever, there is no trim limit switch or trailer nothing but in and out, I'll trim out more and more if I go a little too far the prop blows out and RPM's spike then I'll trim back in as little and off I go, don't know if I'm doing it right but with a non working trim guage and no trim limit what do you do?

Thats the way my old OMC Cobra was.The trim gauge did work when it wanted but i learned just to listen to the sound of the drive.I got used to it...

 

[Mkos1980]

Re: How far can I safely trim out drive at WOT?

I believe the arms should be set to 20 3/4in from pin to pin (Center of the pin)