e-tec 75hp best heights?

[salar600]

I fit a new E-Tec on my boat and based on this tread recommendations

http://forums.iboats.com/showthread.php?t=369057

I?m trying to fix it at the best heights and I?m confused with results?

I ran the boat with the engine at the 2e hole. Ventilation plate was about level with the bottom of the transom. On the water, it looks like having some water going over the plate.

So I lifted the engine to 3e hole and get back on water. Now, I can see some room between water and the ventilation plate. Boat speed hasn?t change and the engine seems to be more sensitive to trim angle. Many times I heared a Bro? sound like big engine can do. Is this what you call ventilating? Is it safe to have the engine ventilating here and there?

What should I do now?

Thanks for your help.

Mart

 

[salar600]

Re: e-tec 75hp best heights?

Maybe I should tell you :

-It's a 16feet vessel
-did the test with my kid (total weigth 250pds)
-90% of the time we do water ski.

Thanks, Mart

 

[steelespike]

Re: e-tec 75hp best heights?

The right height Is that which does not ventilate too much.
The growl isn't venting; true venting the prop will lose grip and may not bite again until you reduce throttle.Some will tollerate slight venting in order to have the most height.If you have trouble getting the best trim then you may have to lower the motor.You may want to test a few turns as well.Are the holes not staggered to allow a half hole adjustment.Some props will resist venting better than others.Solas amita 4 blade is one you allready know about.There are many others.Others can best tell you which ones and why they work.If you give us the usual details we can tell better if your on the right track.

 

[salar600]

Re: e-tec 75hp best heights?

Thanks,

one more question before to go back on water.

In selecting the best prop do you prefer to have the WOT rpm at the top of range? For this motor max is 4500 to 5500 rpm, 75hp @ 5000rpm.

So what's the best target WOT rpm @ 5000? 5250? 5500?

Mart

 

[steelespike]

Re: e-tec 75hp best heights?

Something close to 5,500 is good.

 

[salar600]

Re: e-tec 75hp best heights?

Things are progressing testing is fun but I still have questions !

I run a BRP 13 3/4 x 15 - 3 blades prop and can reach 5600 rpm when I fine tune the trim.

Should I got to a larger prop same pitch or switch to a 17? In this case which diametre? same or smaller?

Thanks for your help guys I appreciat.

Mart

 

[trendsetter240]

Re: e-tec 75hp best heights?

Things are progressing testing is fun but I still have questions !

I run a BRP 13 3/4 x 15 - 3 blades prop and can reach 5600 rpm when I fine tune the trim.

Should I got to a larger prop same pitch or switch to a 17? In this case which diametre? same or smaller?

Thanks for your help guys I appreciat.

Mart

Your RPMs are right about where you want them now. This also leaves you some room for when you have a heavier load on the boat.

I had that same 15p BRP prop on my 95 70hp rude; it's a very good all around prop.

If you have the cash I'd try out a 4 blade solas HR Titan Stainless prop in 15p. I run one now and it holds on very well with my motor mounted high. I run my motor on hole #3 anti-vent plate about 1.5 inches above the bottom of the hull.

I did a detailed review on the HR Titan in an earlier thread; check it out. http://forums.iboats.com/showthread.php?t=393920