Fuel milage

[seasick]

I had 300's put on my 305 Express, same issue, had to Nurse it to get it up on plane, spoke with Prop Gods (Ken) he recommended setting the motors with Toe Out- I experimented and with the tip of the lower units 3/4" wider than the back, there was a HUGE difference. He said the 2nd step was to have the props dressed for Cup and Progression, I still may do that but the toe OUT was my biggest help!

That sounds like a lot of toe out but the measurement is not an exact science. The angle is more useful but that is hard to measure. With the angle and the motor spacing, you can estimate fairly accurately where the two wakes will cross and typically that will be about 20 to 40 feet aft of the props. Did you measure the toe before you changed it?
My question is what exact reference points did you use to calculate the toe out? The standard for the rear measurement is the centers of the tip of the prop shafts. The forward measure is a bit cloudier. Some say to measure at the leading edge of the gear case, some measure at the tip of the forward gearcase bulge. Some measure at the center rear edge of the mid section. Some even measure at the tie rod.
I also ask if you set the motor trim to 0 degrees ( perpendicular to the keel) or some other angle.
Finally, can you see where your wakes merge?

 

[usmm1234]

That sounds like a lot of toe out but the measurement is not an exact science. The angle is more useful but that is hard to measure. With the angle and the motor spacing, you can estimate fairly accurately where the two wakes will cross and typically that will be about 20 to 40 feet aft of the props. Did you measure the toe before you changed it?
My question is what exact reference points did you use to calculate the toe out? The standard for the rear measurement is the centers of the tip of the prop shafts. The forward measure is a bit cloudier. Some say to measure at the leading edge of the gear case, some measure at the tip of the forward gearcase bulge. Some measure at the center rear edge of the mid section. Some even measure at the tie rod.
I also ask if you set the motor trim to 0 degrees ( perpendicular to the keel) or some other angle.
Finally, can you see where your wakes merge?

Very good info. When I ran a Johnson dealership in the 80’s. Everything was 26” centers for duals and toe out 1/2”. That’s ancient history now. I have been calling on Grady Engineering for 30 years. When I was shopping for an older 330 to repower , they told me NOT to move the engines no mater what anyone told me. I took that as the wide spacing of the motors to be important.
I’ll be happy to call my buddy’s up there when they come back from shutdownand ask them about toe adjustments. The PowerTech people are also a great source.

 

[usmm1234]

Very good info. When I ran a Johnson dealership in the 80’s. Everything was 26” centers for duals and toe out 1/2”. That’s ancient history now. I have been calling on Grady Engineering for 30 years. When I was shopping for an older 330 to repower , they told me NOT to move the engines no mater what anyone told me. I took that as the wide spacing of the motors to be important.
I’ll be happy to call my buddy’s up there when they come back from shutdownand ask them about toe adjustments. The PowerTech people are also a great source.

We always used the tiller arm hole and prop shaft for measuring.

 

[seasick]

We always used the tiller arm hole and prop shaft for measuring.

That's the easiest way to measure but it cam be misleading. Since the tie rod (tiller) bracket is farther forward, the toe out measurement for the same angle will be larger than if the measurement had been made at the rear edge of the exhaust housing (mid section) or the leading edge of the lower unit gear case. hat is why I am confused about how folks measure it.
Now if one could place two lasers, one on each prop shaft, perfectly centered and aligned, and both perfectly aligned toe out would make the two beams cross at some point aft. If the beams were shot at a 'target' like a white board, you would at some distance see two dots. By moving that target board forward or aft, at some point the dots would both hit the same spot. That distance would be where the wakes meet. One addition plus of this method is that if the motors ate trimmed to exactly the same angle, the two laser dots would also be aligned vertically.
My point is that the only parameter that really matters is the angle of the motors relative to straight. Depending on where you measure the difference in distance (tiller bracket, read edge etc., that measurement will be different in each case but the angle hasn't changed (assuming that the measurement points do not line up as measured from the 'center' of the motor.

The more I think about it, the more I like the idea of a laser that can be attached to the prop shaft and either perfectly centered or capable of being calibrated. Maybe I should patent this idea

 

[Fishtales]

excellent info above... thanks

 

[Heartly Fishing]

That sounds like a lot of toe out but the measurement is not an exact science. The angle is more useful but that is hard to measure. With the angle and the motor spacing, you can estimate fairly accurately where the two wakes will cross and typically that will be about 20 to 40 feet aft of the props. Did you measure the toe before you changed it?
My question is what exact reference points did you use to calculate the toe out? The standard for the rear measurement is the centers of the tip of the prop shafts. The forward measure is a bit cloudier. Some say to measure at the leading edge of the gear case, some measure at the tip of the forward gearcase bulge. Some measure at the center rear edge of the mid section. Some even measure at the tie rod.
I also ask if you set the motor trim to 0 degrees ( perpendicular to the keel) or some other angle.
Finally, can you see where your wakes merge?

No idea, but what I did do is first measure the motors as they were mounted (toe -in 1/2") performance out of the hole sucked, then I adjusted the toe and tested, My max with the threaded rod adjustment was 1/2" Toe Out, much improvement, so I added some threaded rod to allow me to go a bit more, 3/4" was the winner, that's from Cone Center to Prop shaft nut center.

I have no Idea of wakes crossing, etc, but my performance is better out of the hole, it did NOT affect top end (42) or the best cruise fuel economy (1.5- 1.6 MPG). I would not be opposed to tinkering with props also, but the toe-out adjustment worked and did not cost me anything.

 

[seasick]

Good info but one more question: Toe out or toe in
When you are standing behind and facing the transom, your toes on your feet represent toe in vs toe out. It's easier to think of it as it would be if you were driving a car
So if the measurement between the two prop nut centers was LESS than the measurement between the two forward edges of the gear case, then you have Toe-Out, not toe in. In other words, the center lines of the motors will cross aft of the boat.
Some twins do get set up with toe in and some get set with zero toe.Yamaha seems to spec toe out.(prop shafts angled towards each other)
I will be experimenting with on my boat with the Mercs in the spring and will post what I find.

 

[Heartly Fishing]

Seasick
Good info but one more question: Toe out or toe in
When you are standing behind and facing the transom, your toes on your feet represent toe in vs toe out. It's easier to think of it as it would be if you were driving a car
So if the measurement between the two prop nut centers was LESS than the measurement between the two forward edges of the gear case, then you have Toe-Out,

Yes- Correct

 

[usmm1234]

Toe in is to have the front of the motors aimed towards one another slightly.