Can i trim too high at WOT?

bwachob

Cadet
Joined
May 3, 2012
Messages
17
Hello all. Fairly new to boating. Bought a '97 Ranger, 17', with Mariner 125 last summer. I am always afraid at WOT that I might trim too high and pull the water intake out of the water. Is this possible?
Thanks.
 

Part-time

Chief Petty Officer
Joined
Jul 5, 2011
Messages
536
Re: Can i trim too high at WOT?

The prop would most likely ventilate and loose it's grip before you ran out of water to your intake.
 

EddiePetty

Lieutenant Junior Grade
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Aug 25, 2008
Messages
1,008
Re: Can i trim too high at WOT?

If you trimmed that high your engine would exceed red line and your speed would reduce....porpoising would likely be severe.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
Re: Can i trim too high at WOT?

Water intakes are setup (on Mercs anyway) to pick up water at high trim angles. Where you get into trouble is with a jack plate whereby you raise the engine to the point where you start to expose the inlet holes. What the guys do then (per Walleyehed) is to just plug the upper couple of holes and continue doing what they were doing.

As the other guys said, before you do that, with a normal transom mount, the prop will start coming out of the water causing an increase in rpms and loss in mph. I had a 17' ranger with a 115 Merc and I'd trim out to get my max mph while watching both gauges. When what I said started to happen I would just tuck her in a tad till things went back to normal.

Besides, you have an OT alarm that will sound if your block internal temp gets to about 195F.

HTH,
Mark
 

bwachob

Cadet
Joined
May 3, 2012
Messages
17
Re: Can i trim too high at WOT?

Thanks so much for answers. I would like to post more but find most all of my questions are already answered here. Keep up the great work.
 

Home Cookin'

Fleet Admiral
Joined
May 26, 2009
Messages
9,715
Re: Can i trim too high at WOT?

part of learning your boat is to practice finding these edges. At different speeds, try trimming your motor up slowly. At high speed you will cavitate and the engine will race when you hit top but you will still be drawing water. Also if you are trimmed up high, you will cavitate on a hard turn--just slow down to solve it. You won't hurt the motor with a momentary slip.

At low speeds (shallow water running) you can pull the motor way up and still get cooling water; your prop will be chopping air and you compromise your steering. Again, lower back down in slow increments to find a sweet spot. It's unlikely you'd lift high enough to pull th eintake out of the water but a momentary won't hurt. Outboards are tough. Someday you will accidentally start it when it's raised out of the water--no biggie; just don't make a habit of it.
 

aerobat

Master Chief Petty Officer
Joined
Jun 1, 2011
Messages
835
Re: Can i trim too high at WOT?

your prop will blow out before the intakes come out so you will have a sure sign something is seriously wrong when you overtrim.

my last boat ( evinrude outboard ) blew the prop out when trimmed over edge- my current inboard shows you more peacefully when its too much on trimming -starting oscillating and bowjumping even on calm waters.
 

greenbush future

Lieutenant Commander
Joined
Aug 28, 2009
Messages
1,814
Re: Can i trim too high at WOT?

once you learn your rig, and how it operates, it will be so easy to trim, you will be able to see the rpm's change and performance increase/decrease. It's so rewarding and cost effective to operate at peak performance, instead of plowing or skipping. Gas is costly and so is repairing a busted out-drive or leg.
 

agallant80

Commander
Joined
Oct 25, 2010
Messages
2,328
Re: Can i trim too high at WOT?

She will let you know when she is not happy. Like most people said when you trim too high you lose power and your rpms shoot up. You will learn this quickly. Most boats if you have a trim gauge will be happy at about 1/8-1/4 at most trim. If I start getting close to the 1/4 mark I will lose power and I just click it back down.
 

bwachob

Cadet
Joined
May 3, 2012
Messages
17
Re: Can i trim too high at WOT?

Trim gauge hasn't worked since I got the boat. Not sure if its the gauge or the sending unit. Needle is showing full trim up.
 

dan02gt

Chief Petty Officer
Joined
Aug 30, 2012
Messages
463
Re: Can i trim too high at WOT?

You can't over trim that engine under power. It will not let you! It will let you trim higher to go into shallow water mode at low RPMs but that's it. You have two ranges tilt and trim. When your running under power your in the trim range. The upper range is the tilt range and it is there to trim it all the way up when the motor is off or at idle. If you start with the motor off and all the way down and trim it up you should be able to tell when it goes from tilt to trim mode by the sound of the pump and speed at which it moves the motor.
 

bwachob

Cadet
Joined
May 3, 2012
Messages
17
Re: Can i trim too high at WOT?

That makes since, a buddy of mine said that under power the motor would not let you trim up too much.
Thanks
 
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