Engine Mounting on Transom

[boscoe99]

From the Yamaha Performance Bulletins
( Outboard Performance, Performance Bulletins | Yamaha Outboards )

Pic below is for my boat, FROM Yamaha.

Engine is supposed to be SET at the second hole (mounting HEIGHT, # 2)
(mine isn't, BUT should be), but in black and white, the "bracket
hooks" are likely there for initially hanging the engine

Not really. A PB is not saying/telling/suggesting at what height the engine is to be mounted. It is only saying that on that particular boat and motor configuration that is the height to which it was set.

Most boat makers/dealers mount motors at a height that is least likely to cause a problem for them. They don't want comebacks. Nil consideration is given to performance optimization.

Same thing with propellers. A PB is not saying what brand/model/pitch propeller that should be used. It is only showing what was used for that particular PB. Most PB's use propellers that have too much pitch for real world use. They result in the motor being over propped.

[TownsendsFJR1300]

Not really. A PB is not saying/telling/suggesting at what height the engine is to be mounted. It is only saying that on that particular boat and motor configuration that is the height to which it was set.

Most boat makers/dealers mount motors at a height that is least likely to cause a problem for them. They don't want comebacks. Nil consideration is given to performance optimization.

Same thing with propellers. A PB is not saying what brand/model/pitch propeller that should be used. It is only showing what was used for that particular PB. Most PB's use propellers that have too much pitch for real world use. They result in the motor being over propped.

You missed the point.

Point being the engine CAN be moved up and down
on the transom W/O issue (per Yamaha/Angler)


I can tell you my engine is set the lowest AND is set too deep.

The "brain surgeons" at Angler, when they drilled my 4 holes, the holes
are drilled the "farthest apart". To where you cannot adjust the engine
higher or lower.

Can I re-drill the lower part of the hull, NO...

The bolts/nuts are right next to the well(underneath and not visible-but feeling under there, up against the bottom of the well.

Short of hacking up the "well", ain't happening.

[99yam40]

sounds like you need a jack plate or bracket to solve your motor mounting problem

[boscoe99]

You missed the point.

I did......

[boscoe99]

You don't have to learn me about how engines are hung on airplanes I have much experience with the bolts and attach fittings you speak of...that is my job.

Thanks again.

That is why I used the example that I did. Figuring that you, better than most, would understand that stuff is supported by hardware, not necessarily by structure.

[boscoe99]

Thank for the answer with the documentation from the manufacturer. The Yamaha rigging guide, which I will now refer to and read what they have to say.

For me, Evinrude splains it the best.

[TownsendsFJR1300]

sounds like you need a jack plate or bracket to solve your motor mounting problem

It should be higher, but at WOT, it runs a 46 MPH, white knuckle..

Actually that's (speed) what Yamaha / Angler reports as the performance. I rarely run faster than 30 MPH, 4,000 RPM's (for extended length of time). So for me, it's not worth it...

And what's really odd, is at the rear, bottom "V" of the hull, it's FLAT, maybe 4-5" wide, (going forward about 1.5') before it gets a V shape again...

Might get better mileage, but I can run the entire day (with stops), on 5 gallons, so MPG's are not an issue...

Between the top end (don't need or want any more speed), less likely hood (on hard turns) of cavatating, (as the engine is deeper into the water), I'm not messing with it...

[pstephens46]

That is why I used the example that I did. Figuring that you, better than most, would understand that stuff is supported by hardware, not necessarily by structure.

I enjoy flying with nervous folks. My wife for example. The engines and wings start to pitch up and down in turbulence. "Look at that honey! Wonder how many times that can go up and down before it falls off?" Flaps are good also on landing. They tend to vibrate.

[99yam40]

it is amazing to watch those large wings flap like a bird

[Captn Dave]

That is why I used the example that I did. Figuring that you, better than most, would understand that stuff is supported by hardware, not necessarily by structure.

And in examples such as this, hardware is supported by structure.

[panasonic]

Well I looked in the rigging guide and nothing about having to shim a gap, so something learned today.

Everthing made to flex on airplanes, that what keeps it from breaking off.

"During the test, the wings on the 787 were flexed upward “approximately 25 feet” which equates to 150 percent of the most extreme forces the airplane is ever expected to encounter"

[99yam40]

never sit and watch the wings when going thru turbulance

[panasonic]

That is why I used the example that I did. Figuring that you, better than most, would understand that stuff is supported by hardware, not necessarily by structure.

We had a airplane with that pylon/engine slung under wing design. The engine was hung with (6) 1/2" bolts. Now these bolts where installed vertically (in tension) so all the weight hanging off the nuts.

[pstephens46]

We had a airplane with that pylon/engine slung under wing design. The engine was hung with (6) 1/2" bolts. Now these bolts where installed vertically (in tension) so all the weight hanging off the nuts.

Seems to work well. Except a few 70's vintage DC-10s

[panasonic]

Seems to work well. Except a few 70's vintage DC-10s

MECHANICS were the cause of those engines falling off.Using forklift to remove and hang engines, forklifts are not engine hoists...

The design was sound.