Trimming motor

L

Larry Patrick

New member
Yamaha 150 with permatrim. My inexpierence will show with this question. Im always hesitant when at drivers seat when trimmimg up engine then back down to get on plane,worried about pee stream stopping ,so I only trim up a couple seconds. Am I correct that you will hear change in trimming sound ,when to leave off trim button? Guess im asking how far up should you trim motor without possible stopping stream? Guessing you could trim up till you hear that spot that it changes? I believe im always getting bow down enough feels level. Just wondering if trimming up farther has any advantages? Also I never touch trim tabs when is it good to add these to the mix? When I did the 40 mile trip up the lake in some rough conditions ,there was times that waves I think were quartering into bow not sure if wind was changing but boat felt like it was leaning to port I think that's what im recalling ,guess that would have been time to play with trim tabs? At times we were head on into waves ,other quartering and also hitting from side somewhat. Never had the wind behind us,so we were fighting wind the entire trip. Guess the more conditions you expierence the better your boat handling skills become.
 
Definitely "play" with the trim tabs. Most outboards go from one cylinder trim in the trailer mode to 2 cylinders in the boating/power in the water mode.

You can actually run most motors up to a small amount of the "trailering" mode, at an idle or low speed, and still have the water intake in the water. I often do this to go over a sandbar.

You can watch the gauge, and listen to the sound. These are the clues. No worry with normal in the water trim. You will be kicking up water from the prop by the time you are near an issue with the pickup.

If one trims up too much, you start to loose efficiency--and can even make a boat porpoise…but this is rare. When you trim to the point that line of sight is a problem--you have gone way too far!

Wind behind, leave the trim tabs up. Going into the wind, you can play with the trim tabs all you want. You will learn what is the most efficient running attitude is. I ask Marie to let me know when she is going to one side or the other, so I can make trim tab adjustments as I need to before necessary, or as necessary.

Yes, more sea time, and you will develop reflexes, like riding a bicycle or skiing….or sailing..
 
Larry Patrick":3vrowkfx said:
SNIP When I did the 40 mile trip up the lake in some rough conditions ,there was times that waves I think were quartering into bow not sure if wind was changing but boat felt like it was leaning to port I think that's what im recalling ,guess that would have been time to play with trim tabs? SNIP
Click to expand...

In windy conditions when quartering into oncoming seas, it is normal for the
boat to lean into the oncoming wind.

To correct this with trim tabs, lower the tab on the side of the lean. Ex: if the boat
leans to port, lower the port trim tab until the lean is corrected.

Aye.
 
Agree with all above...don't worry about water pickup.
2 seconds total trim up from a dead stop to best cruising plane is likely far too little for a F150. On the other hand, the only downside is that you're wasting gas and slowing cruise speed by having more hull in the water than needed. (Avoid that if running downsea with large following waves as there is a footnote for every general rule.) There is no substitute for time behind the wheel in your own boat. Calm waters are best for learning the subtle changes control inputs may have. Check your trim gauge at dock or on trailer at full tucked in (negative) trim, should be 1 bar, and at the start of trailering position (sound changes, flashing bar at 5+). The trim sender is a primitive rheostat device between the rams (1 black, 1 pink wire) and activation tab can be adjusted if off. With practice you can tell by the angle of the cowling (looking back) and sound and RPM. At cruise and best trim your splashing will likely appear to be from about 2/3 back from the bow, the antiventilation plate will be awash but not above or under water, and your RPM at 3500 +/- about 500 RPM.
Engine trim is mainly for fore/aft control of how much hull is in the water.
Trim tabs adjust side to side loads and waves (boat will lean into wind and waves otherwise).
One method to determine best trim:
With experienced crew in smooth water, open rear door and with trim full down accelerate from dead stop to 3200 RPM or so and hold there. Then trim up in 1-2 second increments while crew writes down RPM, TRIM, GPS SPEED with each 1-2 second (200 RPM) change. RPM and speed will increase without further throttle. Give each change 10 seconds to take full effect and make some gentle wheel right to left inputs. As you get towards optimum, the higher resistance to turning to the right (in my boat) will decrease, even with power steering.
Eventually you will trim too high and the engines/props will make more/different noise (hard to describe it, but it will be obvious they are less happy) and RPM may increase (props in frothy rather than solid water) but MPH will start to fall off. You can hear it much better with the door open in smooth water. This ventilation (not cavitation) will not harm the engine for this experiment and your engine has a rev limiter @ 6200 RPM.
Trim back down and throttle up to WOT and trim for max speed and note max RPM, which should be as specified for your F150, (5000-6000 RPM for my 2010's) preferably in the higher 50% band (5500-6000).
Again, there is no substitute for hours on your own boat.
Best of luck on the learning curve, have fun, and realize they make both boat and engine fairly idiot-proof at reasonable speeds and conditions.
Choose the latter two for the first 100 hours.
Cheers!
John
 
Thanks for all the expierenced responses a lot of good info. It did feel like boat was leaning with quartering waves,was interesting because new everything was balanced weight wise not to long before that when heading into waves ,after wind change and quartering noticed difference. Will start practicing with trim tabs next outing.
 
Yup. Your prop will cavitate and you will lost power long before you overheat your engine. Far more likely you will overrev your engine than overheat

If you run at cruise speeds and have your motor trimmed all the way down your boat is going to be harder to control. When you are pushing water with your bow the boat can grab a chine and make an unscheduled turn. Especially if you have weight (anchor chain) in the bow.

You want the boat trimmed for conditions, generally running with the bow trimmed down when running into waves, and up when running with the waves. Bow up for running swells, with or against. It's especially important for comfort when running in chop, but the reverse chine and bowsteer can make things scary.
 
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