Engine/Prop height (pictures)

[danamul1977]

Wondering if my motor is set to low. 1990 v-200 merc, on 18' ranger 375v, with 5 1/2" jackplate. RPM's are about 5200-5300, just me with engine trimed up, with a laser ii 25p prop. center of prop shaft is at 10 1/2" vs. bottom of boat at 17". I think you can see all the measurements. I can move it up 3/4" to top notch, wondering if anyone thinks thats a good idea, or just go down to maybe a 22-23 pitch prop, or try different props. Ty for any help.

 

[ondarvr]

The only way to know is to try it.

 

[danamul1977]

The only way to know is to try it.

K probably, was hoping for some magic answer

 

[V153]

If this isn't a joke you need to raise that motor a couple few inches! With a jack plate and 5 1/2 inches of setback your propshaft oughta be much closer to the 'keel' of the boat.

Right now it's hopelessly buried. You can come way up. Just keep an eye on water pressure.

 

[ondarvr]

K probably, was hoping for some magic answer

​Every boat and motor combo is different, then throw in prop styles, how you load the boat, water conditions, etc. and the variables make it so there are no magic answers for motor height and props, just trial and error.

 

[danamul1977]

No Title

If this isn't a joke you need to raise that motor a couple few inches! With a jack plate and 5 1/2 inches of setback your propshaft oughta be much closer to the 'keel' of the boat. Right now it's hopelessly buried. You can come way up. Just keep an eye on water pressure.

Thats what I thought. Well I don't know who did this but they welded the jackplate at its lowest setting. So I can move the motor up 3/4" on the holes but I dont know what to do about this jackplate. You can see the welds. I thought I could go up a few inches, no wonder im running at so low rpm's. (pictures)

 

[ondarvr]

It looks likes it's adjusted to the lowest setting, but can be raised from there, the welds I see shouldn't be stopping you from moving it.

 

[danamul1977]

No Title

It looks likes it's adjusted to the lowest setting, but can be raised from there, the welds I see shouldn't be stopping you from moving it.

The welds on the bottom of these nuts and on the threads are the ones that concern me. not sure what to do. The nuts above the welds would have to move down I would think.

 

[ondarvr]

With the bolts holding the bracket vertically in place loose, you put a wrench on the very top nut and turn it, this will move the motor up or down, right now it's all the way down.

 

[Fed]

I think it's all the way up at the moment and it looks too high to me so there you go that's the internet for you.
Maybe your low engine rpm is caused by something else?

 

[danamul1977]

No Title

With the bolts holding the bracket vertically in place loose, you put a wrench on the very top nut and turn it, this will move the motor up or down, right now it's all the way down.

I think I get it. After I loosen the 4 middle/outer bolts I turn it counter clockwise to raise it, the top/middle nut will just spin in place and not move. Confusing me. You can see where the rust has been taken off of that bolt when it was lifted in the past.

 

[ondarvr]

I'm interested to see what happens, you'll at least be able to dial it in a bit better.

 

[Fed]

I think I get it. After I loosen the 4 middle/outer bolts I turn it counter clockwise to raise it, the top/middle nut will just spin in place and not move.

Nope, loosening the internal side nuts then turning the top nut counter clockwise will lower it.

 

[Sea Rider]

Why is there a jack plate to start with ? check this post, try to duplicate the upper water deflector setting on your combo, report your findings..

http://forums.iboats.com/forum/gene...0431353-help-with-prop-selection-with-numbers

Let's Make Boating More Fun,

Happy Boating

 

[V153]

It is currently all the way down. Actually lower than the holes on the transom.(!) To raise the motor turn the middle (welded) nut clockwise. Then snug the top bolt down to lock it in place. Yes you'll need to loosen and then re-tighten the 4 horizontal bolts. The aft half of the jackplate should be much higher.

 

[V153]

Prop shaft needs to be much closer to the bottom of the boat. Like so: