Help me make my Glen L Stiletto Wooden boat FASTER!! (Advice needed)

[blacktruck]

Also... Trim plates back on and back to being smooth again.

Did this stop the porpoising at top speed? Porpoising will do the most damage to your transom. I would do the static height plate first before getting a new lower, it's a cost effective way of raising the motor. Once you get the motor where you want it, get the right prop. See if you can borrow a couple while you're testing.

Probably tempting to trim it out but it really shouldn't need much positive trim once the motor is at the right height. And raising the motor will reduce drag, helping reduce porpoising as well. Good luck.

[80's old school]

Did this stop the porpoising at top speed? Porpoising will do the most damage to your transom. I would do the static height plate first before getting a new lower, it's a cost effective way of raising the motor. Once you get the motor where you want it, get the right prop. See if you can borrow a couple while you're testing.

Probably tempting to trim it out but it really shouldn't need much positive trim once the motor is at the right height. And raising the motor will reduce drag, helping reduce porpoising as well. Good luck.

When you really trim her out it picks up more speed but at the cost of porposing. With the trim plates on and moderately trimmed, she will run 52-53 MPH all day long without porposing. To get those last few MPH equals too much porposing.

[80's old school]

So while I have been working on touch up paint on the back of the boat and trying to figure out how to raise the motor.... I think I may have uncovered another problem.

About 3 years ago I put the boat in the water to have a nice weekend of boating, and I could not get anywhere without constantly priming the bulb.

Long story short... The VRO pump crapped out.

I had a bunch of folks coming for a day of boating and could not source a new fuel pump. I went to the local VW shop and bought a cheap electric fuel pump and problems was solved.

That at was until now. Now that I am trying to go faster, this past week I noticed the engine would not rev past 5600 RPM. At one time it was only up to about 5400 to 5500 RPM.

I did a fuel flow test yesterday, and I was only flowing 1 quart per minute free flowing into a gas jug. That equates to 15 GPH flow but it would have probably been less at higher psi.

I was was pushing the fuel through a non functioning VRO pump and then through the assembly that has the primer system.

I replumbed the system where the primer still gets fuel, but it Tees off to both banks of carbs. I also added a new electric fuel pump and now I am getting over 2 quarts per minute now. This should be enough for a 115 HP.... I think...

If if I was starving for fuel before, this should help.

I know nay sayers will say run the VRO... No thanks, I prefer premixing and NOT having to pump the primer ball every time I start for the first start of the day. Ever since I started premixing, the motor seems happier and smokes less..... Smokes WAY less....

[80's old school]

So I have been busy. She should be ready to take to the lake next week to see how she performs.

1. Raised trim plates. They are now 1/8" to 1/4" above bottom of boat. They were flush before.
2. Strengthened transom by adding bracing and additional bolting.
3. Reduced almost 100 pounds of weight. Removed excess junk and heavy audio system that was not being used. Also swapped to 11 pound battery. I used these light batteries on my race cars and they work great.
4. Installed Bobs Machine jack plate. Now the center of the Propshaft is 3.5 inches below the bottom of boat. Remember before it was 8.75 inches below.

Hopefully I will pick up some speed.

Enjoy the pictures.

[89LASER]

Watch your water pressure and temp gauge. The boat looks awsome.

[80's old school]

Watch your water pressure and temp gauge. The boat looks awsome.

Thanks for the advice. I will.

I I verified that my water pressure gage and water temp are working correctly.

Hopefully a true 60 MPH is in reach now.

[80's old school]

Well I took her to the lake and took her for a run. I spent most of the day piddling with height adjustments and trim tab adjustments.


First impressions were I had the engine too high. Water pressure still great, but a little too much cavitation on take off. Too much porposing as well. I had the trim tabs up too much and they were not properly contacting the water enough when needed.

Come to find out my pin that sets the amount the motor will come all the way down was set too high. That was fine if I would just give it full throttle and get up to top speed. When I lowered the pin, it stopped the mid speed porposing.

I found out if you lower the trim tabs too much it KILLS top speed.

Overall I had a great day and saw some speed improvements. I had to go to a Lake that had a slightly higher elevation than I ran before and the temperature outside was hotter. But the boat would run right at 60 MPH.

I finally was getting RPM out of the engine. Before I could only run 5600-5800 RPM. Now it will run 6000-6200 RPM...
Holeshot is good and midrange is awesome for 115 HP... The boat felt more alive overall.

Now for some observations and a reality check.... I think I can tweak out a little more with motor height changes and trim tab adjustment.... Then I will probably optimize prop. I run a Stiletto 19 pitch and it has hit a few rocks in its past. I don't think that is really affecting performance much, but I want to get the prop optimized.

Here is my reality check... One of the previous posts on this blog someone stated that I was probably in the "sweet spot" and if I could get 60 MPH out of this rig, I was doing good. Reality is... I think that person is right!!

When you trim high enough to get the boat less wet, it puts her back on the trim tabs and the little 115 just don't have enough ponies to keep her there and she comes back down. When the boat is coming up, you can really feel the speed increase, but when it plows back down, you lose the speed.

I really now feel like the ONLY way to make this boat any faster is with more horsepower...plain and simple..
I am thinking that I should be proud that it runs 60 and is a beautiful boat....


I will report back soon the next time I take her to the lake.. I also am planning a trip back to my hometown in Texas to run the rivers in brackish water with zero foot elevation. I think then she will run strong into the 60's not being at higher elevation and also in cooler temps (when I plan on taking her back.. not todays temps!!).

[olboatman]

The next move that I would make is to see what PowerTech Props has for surfacing props for your motor. They are great people and have an exchange program to get it right that you can't beat. That will let you tweak the hight and keep h20 pressure. JMO Gary

[80's old school]

Thanks for the advice. I will check into Power Tech.

Thanks!

Now i I can't wait to go back to the lake and ENJOY!!!

[80's old school]

Just a little update!!!

I have done some more work to my boat and I am finally hitting the speeds I wanted.

The he latest mods I have done was to get the heads milled by Monty Racing and put oversized main jets.

I also bought a new Stilletto 21 pitch prop to try instead of my previous 19 pitch.

While I still need to work on some "drivability" issues, I am definitely hitting some impressive speeds.
With the 19 pitch prop and stock engine, I could do a smooth 50-52 mph and trim up to a very bouncy porpoising 58 ish MPH.

Now I can easily run 55-58 MPH absolutely smooth and then when the water has "just the right ripples" I can trim to where it bounces and then just keep trimming.... Then it finally gets up and hauls ass! I am now spinning the motor 6200 RPM and it will hold an easy 65 MPH!!!

I still need to do some work on the transition between idle and accelerating. It is too lean in the intermediate range. I have ordered two different sets of smaller intermediate air bleeds. This will richen the mixture. Right now it either bogs or dies trying to come on plane. Modifying the timing arm to where it brings the timing advance on faster really helped with the bog. I kept the total advance alone. With the 19 pitch prop, the transition is not such a big deal.

Another thing i dont like is I have the infamous 60 degree Evinrude "rattle" decelerating with high compression heads. Funny thing is it only rattles with the 19 pitch prop... It does not rattle on deceleration with the 21 pitch prop... That is puzzling.

Also so the bigger pitch prop does not idling low in gear. The lower unit seems to make a "clacking" noise if the RPM is too low. If I speed up the RPM just a little, it is smooth.

So guys, any idea how to help the decel knock or the low RPM rattle in the gearcase?

I am hoping richening up the main and intermediate will help with the decel knock. It is really unnerving.

Anyhow, I am done trying to make it faster. 65 is fast enough and very respectful for a 115 Evinrude.

Any suggestions on why I have to trim the motor excessively to get the speeds up? I still can move the engine up about 1-1/2" more. Maybe this would help me from having to trim so much.


Now i I just want to do some fine tweaking to make it is friendly as it was before I started messing with it!!

Thanks to everyone who gave me advice to make my Glen L fly and scream!!

[brocluno]

First, let me say great boat and beautiful version.

Second, getting 60+ out of a 115 is doing your homework. You are in the MAM Club (Mile-A-Minute) and that's a big step, well done

[80's old school]

First, let me say great boat and beautiful version.

Second, getting 60+ out of a 115 is doing your homework. You are in the MAM Club (Mile-A-Minute) and that's a big step, well done

Thank you! I know it's been a while, since I posted, but it has been a long winter and many other car projects have taken over.

Now it is warming up and I am ready to hit the lake again.

I bought some jets to fiddle around with to help with the off-idle transition issues I was having last year, as well as richen up the mixture a little more to help with the off (high speed run) slight rattle I am having with high compression heads.

After the last post I did last year, I took the boat out again one more time before winter hit and it went 65 again several times. It took slight ripples on the water and then keep trimming out and ride out a little porposing. Once you got it past a 55 mph ish porpoise, it immediately raised the RPM of the engine and the speed increased.

I am through with speed mods. The boat does what I want. Now just fine tune and enjoy!!

[Mr. Demeanor]

You need to get that motor up with a low waster pickup and put on a chopper and see what happens. Prop will make a huge difference in your setup. My little boat is literally undriveable with a cleaver and on rails at 101mph with an ET. The cleaver porpoises so bad the whole boat gets airborn. Almost no hop with an ET.

With a bone stock Yamaha 130 my boat 65mph with a prop like yours and the motor buried. 85mph with a transom mount water pickup and an ET style prop. These little motors just dont have the grunt to push a greacase through water.

[Wayne Cammidge]

In my Dad's racing hey days of the late 50's and early 60's they would run 55 with a 50 Merc standard out the box.
I was going to say 65 should be very easy to reach, which you have now done.
As said above, better props and set up are going to get you into the 70's, no doubt.
Remember some of those boats from the 60's, could run serious speeds, with old 115 motors of the day, and props that were a joke compared to what we now can get.
Your 115 is way stronger than what they ever had available.
Need to try a prop around 24"P raised until you run out of water pressure
The newer style small hub merc props have interchangeable drive hub assemblies so that you can get them to fit on your engine.
You should be able to find a 24 Lazer II that you can get a kit to convert and then borrow from a mate to try out.

[80's old school]

In my Dad's racing hey days of the late 50's and early 60's they would run 55 with a 50 Merc standard out the box.
I was going to say 65 should be very easy to reach, which you have now done.
As said above, better props and set up are going to get you into the 70's, no doubt.
Remember some of those boats from the 60's, could run serious speeds, with old 115 motors of the day, and props that were a joke compared to what we now can get.
Your 115 is way stronger than what they ever had available.
Need to try a prop around 24"P raised until you run out of water pressure
The newer style small hub merc props have interchangeable drive hub assemblies so that you can get them to fit on your engine.
You should be able to find a 24 Lazer II that you can get a kit to convert and then borrow from a mate to try out.

You our guys are getting me excited to want to go out and play with it (modify) some more... Shame on you..😀😀😀

I have raised the motor on the jack plate but still have room to go up. I still have plenty of water pressure at the height I am at now. I have not had to do any mods to the water pick up yet.

I will I'll be hitting the lake soon. I will report back!