E-Tec 115 Prop issues on 18' aluminum fishing boat

[lostinnd]

First off I just bought my boat and the E-Tec was a big selling point and now if I can just get the prop dialed in I will be set. Here are the details on the setup..

2008 E-Tec 115 Saltwater edition
Serial # 05230824
Model # E115BPXSCR
Has a Stingray hydrofoil on it
25" shaft length (has the V6 gearbox even though my motor is a V4, its a saltwater ed thing I think)

2008 Smokercraft ProMag 182
18'2" hull
dry weight of 1425lbs but it has two live wells and three batteries and tons of fishing stuff so it gets a lot heavier I am assuming

The motor is in the very top mounting hole and the prop is a 14.8" 17 Pitch 3 blade aluminum one.

I believe the previous owner used it for skiing since it has the hydrofoil and a ski pole so I am thinking the prop needs to be changed for fishing use (better cruising, higher top end speed).

It has a great hole shot when trimmed all the way down and is on plane almost instantly but it tops out around 35-37 mph gps depending on how many people are in it. Also the RPM at WOT is around 6000 to 6200+ when I vary the trim. I am thinking the boat should be faster than that and I know the rpm's are way too high. I don't really care about the hole shot but I would like more cruising speed and to lower the rpms to around the operating range of 5500-5600. Also any suggestions on whether I should go stainless or 4-bladed would be great. Where would I look to buy a prop and do they have to be E-Tec specific? I have owned a couple smaller boats but never messed with props at all. I am thinking I need to pick up something with a higher pitch?

Thank you very much!

 

[steelespike]

Re: E-Tec 115 Prop issues on 18' aluminum fishing boat

Hmmmmm?V6 gearcase is 1.86 gear ratio. assuming it retains the V6 gears.
It appears the stock 115 with 2.00 gears typically runs a 17" prop on 17-18 ft aluminum
outboards with speeds 37-42 rpm about 5600 to 6000.etec site says 5800 is the max rpm.
it seems that if your running 1.86 gears
with a 17" wouldn't be over revving I would get rid of the foil till we determine an ideal setup
and then decide on a foil.Does the 182 have a 25" transom?
I wonder if they are cheating the 25" motor up to fit a 20" transom?
Did some research it is for an extra long shaft.

 

[lostinnd]

Re: E-Tec 115 Prop issues on 18' aluminum fishing boat

Yes it looks like it has a 25" transom. At least the motors they recommend for it have a long shaft. I am thinking maybe the motor is mounted too high? It does feel like the prop is slipping at WOT and when turning it definitely does. Would the foil really cause that many problems? I put one on an old boat and the only thing that changed was the plane speed.

If I put my numbers in a prop slip calculator it shows 37.5% slip? I am thinking something is definitely wrong with the setup and like you said maybe the prop isn't the issue and a different prop might just be a bandaid or cause even worse issues.

Thank you very much for your help so far, I am hours and hours away from a decent mechanic so I am pretty much on my own.

 

[lostinnd]

Re: E-Tec 115 Prop issues on 18' aluminum fishing boat

Well it appears as though even though it supposedly has the V6 gear case the gears are infact 2.25. This still shows a ton of slip though. Should I start out by removing the foil and possibly raising the motor up?? I was confused and thought that since it was in the top hole it was highest out of the water when in fact it is the lowest.

Thanks again!

 

[steelespike]

Re: E-Tec 115 Prop issues on 18' aluminum fishing boat

The foil could cause lower speed if it in the water at speed lower speed would usually result in higher slip indication.
If it makes the boat lay down too much that could add slip because the can't make the speed it should.
Also the large gear case probably adds a little drag probably couldn't measure it but some.
Don't worry about the holes left behind it won't bother anything.
Is the anti vent plate(just above the prop) about even with the bottom of the transom?
When making any changes do one at a time and test.Otherwise there's no way to tell what helps or hurts the results.Standard gears are 2.00 Is the 2.25 exclusive to the 115 V6 gear case?
The foil might be reducing the venting but we need to know what it does.
Its normal to have to reduce trim and throttle when turning.
also its not unusual to run at less than maximum trim and make best speed.
is the prop By Evinrude/BRP?
Further thoughts Using 6000 rpm 2.25 ratio ,17"prop, 37mph I get about 13% slip
using 6200 I get about 16% Not sure where your getting 37%?
If you think about it 37 isn't that far from what 115s are doing with a 2.00 ratio.
38-42 It does appear that a 19" prop could get you about 5600 rpm and about 40 guessing 10%
slip.

 

[lostinnd]

Re: E-Tec 115 Prop issues on 18' aluminum fishing boat

Thanks again, I am going to check all of that stuff over the next day once I get off work. I will probably start by finding the right mounting height and getting the anti ventilation plate just out of the water at wot then try removing the foil. Yes it appears as thought the Etec 115 with the long shaft and V6 gear case has 2.25 gearing. The foil is a really big one so if it is mounted too low it is probably dragging really bad and slowing me down. I will have to check on the prop manufacturer and thanks for all the tips, I really appreciate it!

 

[lostinnd]

Re: E-Tec 115 Prop issues on 18' aluminum fishing boat

Update finally!

I raised the motor up to the third hole from the top and removed the hydrofoil. My rpms have lowered slightly to about 6000-6200 WOT. Hole shot is about the same but it takes longer to come on plane. There is a noticeable difference in handling, it seems much more responsive but I had the prop blow out a couple times while turning sharply but this was in large waves so that plays a part too. Also speed may have decreased but it is around 35 mph.

Since I have a 17P aluminum prop I am thinking a 19P stainless would be perfect to drop me down in RPMs and gain speed, does this sound correct?


Thank you!

 

[steelespike]

Re: E-Tec 115 Prop issues on 18' aluminum fishing boat

Usually suggested to make one change at a time and test.
Doing both makes it difficult too evaluate either one.
It does appear you need more pitch and a ss prop should at least help with the slip
and may resist venting while adding speed.
Going from one material to another does introduce some unpredictable results.

 

[1FASTLASER]

Re: E-Tec 115 Prop issues on 18' aluminum fishing boat

I never heard of a V4 ETEC having a V6 gearcase. What I do know for a fact is the V4 ETECS around here on bass boats respond very well with the Renegade 4 blade stainless.

 

[lostinnd]

Re: E-Tec 115 Prop issues on 18' aluminum fishing boat

After more time on the water it looks like I need to go up in pitch quite a bit. With two people, livewell full, fishing gear, etc, I can still push 6400 RPMs out of the Etec at WOT. I think my rpms have gone up expectedly after raising the motor to the third hole and removing the hydrofoil. At 6400 I am getting 35.5-36 mph. I run it at around 5500 while cruising at 30ish mph and it seems to run best here.

I am thinking that since I have a 17P brp aluminum prop that a 19 or 20P Viper would get my rpms down and speed up. I may end up going to a 4-blade to help out in the rough water but for now I want to get a 3 blade SS prop and get my rpms dialed in.

Had some issues with bad gas I think causing my Etec to die while idling and not wanting to start so its been a while since I have had it on the lake wide open.

Am I on the right track here?

Thanks again!

 

[steelespike]

Re: E-Tec 115 Prop issues on 18' aluminum fishing boat

I don't have any info on the Viper but your numbers do bear out a prop change similar to your thoughts.
Unfortunately going to a SS introduces some variables like it may get the hull up better tempering the rpm reduction of the pitch change.Stick with a 3 blade for now no need to introduce another variable.

 

[Dhadley]

Re: E-Tec 115 Prop issues on 18' aluminum fishing boat

Your motor should be a DPXSCR which has the V6 STYLE (size) gearcase but has it's own wierd gear ratio (2.25:1). That motor should be a 25" motor which goes on an X-long transom. Long shaft motors & transoms are 20" (about).