New 2010 Suzuki DF90A + 26X = BIG Success!

[darrenj]

I did not even ask if the dealer would install it. I told them it was for a pontoon type boat (it made sense that I asked for the 13 pitch prop) and that I would install it myself.

It really behaves like a power boat when in wake board mode. The difference between the completely empty boat and the loaded boat is unbelievable. Can't wait to try wake boarding behind it. I will keep your advice about powering up in mind.

We upgraded from the original 1998 Nissan 50 HP two stroke. It was really loud even idling and got 3 MPG at 6 MPH boat speed. Above 6 MPH was really not possible as we could burn through 6 gallons of gas in 30 minutes and get about 14 MPH. The noise was deafening.

Our main goals in order of importance were:
1) Reduce noise in the cockpit when at cruising speed ( 6 to 7 mph for us).
2) Increase range by improving fuel economy at all speeds. The ability to cruise faster when time was a factor.
3) The wife and kids wanted to increase the fun factor. Tubing, wakeboarding, waterskiing.

The Suzuki is whisper quite at idle and very quite at 2200 RPM and less. We can now enjoy talking and music while under way.
From what I have read the fuel economy should not be much worse than a 50 or 60 at hull speed. Once I get the engine interface upgraded from version 2.7 I will post fuel economy info.

[sirlandsalot]

Don t men to hijack this thread, But can anybody recommend a prop for a Suzuki 70? I am touring now with my family, lots of weight and I get 15 mph at 4100 rpm WOT...?

Is this normal?

Thanks

[darrenj]

If the boat was originally purchased from BWY then it likely has a 14 * 13 prop (14 inch by 13 pitch).
I have the 90 HP version of your motor and the prop is borderline to much prop for me and I have a 26X which from what I have read can handle more prop than a 26M.

If it is a suzuki prop then you should be able to see the prop info stamped on the prop.

If the prop is more than 14 * 13 then that is likely your problem.
If you have the 14 * 13 then I would expect you to get more than 4100 RPM at WOT so I would look for other problems. Things like the controls not opening the throttle all the way or motor mounted incorrectly etc.

[darrenj]

Do you know what your top speed and rpm is with the boat lightly loaded?

[sirlandsalot]

I always seem to be loaded......big family and a prego wife, lot's of girls so lot's of stuff. Maybe I should try emptying it and motoring?

It was a BWY boat so I will check the prop in the am when it is light out. I have noticed a bit of slop in my throttle control as we'll so maybe you are right and I should look at linkage.



Thanks you guys very much!

David

[darrenj]

BWY has some info on the engines they have compared:
http://www.bwyachts.com/engines.html

Much of it is justification for their choice to go with Suzuki so there is what some might consider bashing of other motor choices.

Sounds like max speed on a boat with the df70A is 24.6 MPH. Assuming that is for a completely stock boat.
Punching some numbers into the prop slip calculator makes me think that a stock boat will have a max RPM of around 5200 @ 24.6 MPH.

Using my numbers as a baseline (I lost almost 9 MPH and 1000 RPM) for a heavily loaded boat makes me think that you could just be over propped.

Here is my known info:
Wake board configuration (pretty much stock but without mast): 31.4 MPH at 6300 RPM
Loaded for bear, no ballast( mast up): 23 MPH at 5300 RPM
I feel that I am over propped as if I was actually pulling a wakeboarder and had another person spotting on the boat I would not be able to get to 6300 RPM.

Here is your info (stock numbers are based on BWY and guesses)
Stock per BWY (probably with mast up): 24.6 MPH at 5200 RPM
Loaded for bear, no ballast: 15 MPH at 4100 RPM

If I were you I would test with your boat as light as possible to confirm the stock numbers above are correct.
If they are then you are over propped and getting a new prop would most likely help a ton.

There are some people running 14 * 11 props but even that might more prop than you need. Unfortunately getting the right prop seems to be more art than science.

Maybe some other people running the DF70A will share some info about their experiences with it.

The other thing you could do is call BWY and talk to Todd. If anyone might be able to provide you with a recommendation based on experience it would be him.

[Tomfoolery]

Since the feedback mechanism is actual performance in whatever real-world conditions are prevalent, I can't come to any other conclusions than the boat is over-propped for it's intended use, which includes all the 'stuff' (people included), bottom condition, fuel load, wind/water conditions, etc. If the engine isn't getting up to speed, after confirming that the throttle is actually pegged (at the engine), and that the tachometer is actually correct, then the only thing to do is go with a shallower pitch prop.

There's nothing wrong with having more than one prop, by the way, for use under different conditions. Aluminium props are relatively cheap, and having a spare, even if not the ideal pitch, is always prudent, with the tools to change it.

I use a 4-blade Solas for pulling a wakeboard, and the Honda-supplied 3-blade prop (actually made by Solas, too) for everything else. Takes a minute or two to change. If doing it in the water, hang an old umbrella under the OB when doing the work, as it's real easy to drop a part or tool in the drink.

[beene]

Hey Tom....

You gonna surprise us with a shinny new Suzi 90 when we see you in a few days....

[Tomfoolery]

'Fraid not. Same ol' same ol'.

[fdnynapes]

Thanks for the work you did.
I bought a used 26M with this engine. It only goes 18 K, I will be buying this prop.
Btw I recently had idle problems, the mechanic replaced an IAC valve. It gets clogged with carbon.
$800 and change. You can remove this valve yourself and clean it.

Rich N

[vkmaynard]

For anyone interested Blue Ridge Propeller Repair (Jason Spence-Owner 276-340-1597 or 276-629-2274 email: proprepairs@yahoo.com) purchased two of the Solas 3413-138-15 (13.75 x 15) Amita 4 blade props to re-pitch for the 2010+ DF90A. One is for our spare prop. I asked to have a little more pitch removed for Mast up loaded condition. We are sending in our original also to get re-tuned after touching the sand bottom.

This the shop that got our boat to 31 Mph.

He will probably sell the other if asked.

Victor

[vkmaynard]

Still running strong.

No structural issues.

Victor

[darrenj]

Same here, running strong and no structural issues. 800 hours on the engine.