How to Tell if Your Outboard is Mounted Too Low

During the sea trial of this Remanufactured 175HP Evinrude Tim, owner of Outboard Exchange in Waterford, CT, realizes the outboard is mounted too low. He explains how to tell and how it affects the overall performance of your boat.

[@zacksrandomprojects9698]

Always film horizontal

[@armytruck08]

It’s funny I have had a Yamaha 30 2 stroke for about 20 years , then I decided to upgrade to a Yamaha FH four stroke brand new 2022 . Both outboard motors lined up bang on my 20” transom to the keel lining up straight off the keel . I just picked up a brand new 14 ft. Same exact hull as the last boat however, I went with a mercury 25 new four stroke and it sits 2” below the keel . Measures the shaft length and its 22” shaft 🤔. I went looked at other new ones and are the same22”. Yamaha ones are 20” . Why is that ? . Now I need to raise the motor above the transom to avoid that spray and drag I’m getting. Or maybe go back with a Yamaha FH25 FS

[@machew2009]

You could hear it in the engine that it was working less once you raised it up

[@benjaminallen2370]

Much better, I agree. Mine was 1 hole too high from factory (parker-yamaha powermatched) as there was ventilation and porpoising. All solved lowering 1 hole.

[@Suprafly954]

Why didn't he just explain this with the motor off?

[@Oexchange]

This was a motor that we Remanufactured and installed using the same holes the previous motor was installed on. On the sea trial we realized the motor was mounted too low and had to be changed. This is why sea trials are so important.

[@johnny_jgs2435]

Hi man what to do ihave new Boat new motor boat fiberglass 4m new Yamaha 15 but motor it's about 5cm up then the bottom off the Boat

[@Oexchange]

Can you send us a picture of the back of the boat? You can send it to our email info@outboardexchange . com

[@johnny_jgs2435]

I sent you email thanks

[@A5JDZK]

Your camera angle is off. Otherwise good vid.

[@stanleybest8833]

That motor is way too big

[@Oexchange]

The boat is rated for that horsepower. Thanks for watching!

[@chiphill4856]

He won't need those tabs with the new motor height. They were installed trying to compensate for the motor being too low.

[@harrisondirks9540]

Just took my new-to-me boat out for the first time, and noticed it leans starboard right as I get on plane. I've read that this can be solved by just powering through and them trimming up, but this goes against every common sense bone in my body. "Oh your boats listing when under power? Just go faster!" Maybe it'll work, or maybe not. I'm going to try shifting it up and hopefully this helps. Thanks for the video!

[@Oexchange]

Hey Harrison, check out our other video on adjusting your steering tab. That may help with your leaning issue kzbin.info/www/bejne/kJiQZWxmh6ZgmZY

[@Mahalo_83]

Is the helm on the starboard side?

[@Steve-yh1pj]

If it's a deep v hull, it's quite common with one person on board for the boat to lean to the side the driver is on. If it's just steering starboard could be torque steer and you might consider hydraulic steering. Regarding engine height check first that the top of the cavitation plate is level with the right part of the keel first before adjusting there are lots of videos around for that.

[@harrisondirks9540]

@@Mahalo_83 Yes, single console on the starboard side.

[@CohlFam]

How do you notice the motor is too low after you install it. You can measure and line it up from the get-go. Major oversight.🤦‍♂️

[@Rumplestiltskin777]

I can hear the difference

[@visualkeirockstar]

Does raising the motor changes rpm? I have a 115 Mercury pro xs with a 19p stainless steel prop only getting around 4800 rpm at wot.

[@Oexchange]

Yes, it usually goes up if the height is incorrect.

[@realrecognizereal3758]

Maybe you need 2 drop on your prop pitch if you want to raise you rpm on wot. So maybe check 17 pitch prop.

[@visualkeirockstar]

@@realrecognizereal3758 It still won't get there with a stainless steel. I have to run a 17 pitch prop aluminum. The average speed I get is only 38mph. Most of the video I see with this motor with same size boat 18' get 44-48mph.

[@realrecognizereal3758]

@@visualkeirockstar might be weight but only way for you to reach the correct rpm on wide open throttle is 2 correct your pitch or diameter drop your pitch an inch you will gain 200rpm every inch reduced. Drop your diameter size. Every inch you subtract from the diameter will raise your rpm by 500 rpm

[@pfpublius]

I'm facing similar issues. New to me skiff style double hull. Has a 90hp 2 stroke Yamaha. She squats bad and had exceptionally terrible hole shot. I've been told that my motor is too low & my prop is bad. The ventilation plate is exactly inline with the bottom of the hull. My motor sounds sluggish like your first trial run did too. I'm thinking both things may be the problem for me, but I'm not sure which order to address them in to get the best result. Any advice?

[@Oexchange]

Can you tell us the pitch of the prop and the make of the boat or pictures? If you want to call or email us we can help solve the issues with you. Pictures of the boat would be great!

[@AB-bg1or]

I have a 16’ Wahoo (Whaler copy) that is mounted as high as it can go. The only solution I see is drilling new holes for the lower mounting bolts. The lower unit is about 2 inches too low. Thoughts?

[@Oexchange]

If you'd like you can send us some photos to our email and we can help you there. [e-mail]

[@Steve-yh1pj]

Is it possible that the engine is too long for the size transom you have?

[@ckkendrick7861]

Will 2inches make that much of a difference?

[@fishingismydrug1]

Did you figure it out? What about a jackplate?

[@fishingismydrug1]

@@ckkendrick7861 YES ! It can make a world of difference.

[@makingcookingfixing]

Could you maybe help me, on a Boston Whaler Dauntless, I have a 150 Optimax, but on the right of it a helper motor 8hp, Since the boat has a V hull, the right side is higher (or transom is shorter) what would the correct height be for the outboard engine? Should the cavitation plate be on the waterline? Thanks.

[@airtightindustries]

I would say it doesn't matter because you're not going to plane was 8hp. But I'd like an expert multi main engines to give to give a setup guide on twins, triples, quads etc

[@makingcookingfixing]

@@airtightindustries Exactly, the helper engine I got is a short shaft, luckily on an adjustable height bracket, but still, all the way down, the cavitation plate is on the waterline. I haven't tried running it in the water yet.

[@trentc6069]

I've got a 2007 dauntless 180 and I feel like my 150 optimax is way too low. It's at the lowest mounting hole...

[@makingcookingfixing]

@@trentc6069 I have the same feeling of mine. I am only doing 30mph with the 150 optimax, what’s your max speed? I have a ss mirage prop, I was thinking to put back the original prop

[@charlesstiles8904]

Cavitation plate needs to line up with the bottom of the hull. That's the starting point. After the boat is loaded with gear and people then you adjust it up according to the water line. Cavitation plate should just be submerged.

[@t.j.goldwater]

Depends of the boat of course . You can’t have the propeller spinning behind the transom .

[@dsciarrino3663]

The best money can

[@danmanthe9335]

I've got a 60 year old 10 horse. I don't think it really matters

[@TEKKKNO]

I've similar problem with short shaft motor set little bit low ,it makes sides splash in middle throttle

[@froggerman44]

And how do I tell if it’s too high?

[@gypana]

It would be cavitating more often especially if you trim out or turning.

[@Hajsansvejsan]

The propeller does not get wet

[@gypana]

@@Hajsansvejsan Oh a joke, i get it now

[@tcap7917]

With the boat on plane and properly trimmed the anti-ventilation plate should be skimming the surface of the water, not above it.