New member and new Suzuki owner DF40A

[mrpister]

Sorry for the delay. I have installed the 60 silencer holder. Prop testing begins in the next few days.......weather permitting.

[bythesaint]

For around $5 I bought the non-restricted version of the air intake "seal" and installed it in my motor yesterday, supposedly converting it from a 25 HP to 30 HP motor. So in theory, I'm comparing performance with a 25 HP motor to performance with a 30 HP motor.

Hi, does the df30 intake seal parts number is 13832-94L00 ?
thanks

[2014DF25ARS]

Hi, does the df30 intake seal parts number is 13832-94L00 ?
thanks

Yes, I ordered from Browns Point: Silencer Seal (13832-94L00) to install on my DF25A.

[mrpister]

My results. Boat is a Lund 1600 Fury. Two people on board. Tested over a few days, various conditions. all low winds and waves.

Averages:

14" stainless

34 MPH and hits rev limiter at 6200

15" aluminum

34 MPH and also hits the limiter, but rarely.

16" aluminum

36 MPH and max RPM was 5900

Cruises at 34 MPH around 5700 RPM.


Turns were better with the stainless of course. I have to trim down the aluminum props on sharper corners so they don't vent.

The 60 holder definitely provides more torque and gets on plane much faster. As noted, it sounds more impressive as well.

I will stick with it. A simple mod to gain considerable HP and torque. I am glad I looked at all the part schematics to discover the air restriction in otherwise nearly identical motors.

[pafnuc]

mrpister Thank you. 16", 36 MPH, max RPM @5900 sounds like sweet spot. I'll check this setup with my 4,5 meter RIB. Cheers and good luck.

[pafnuc]

By the way. Maybe silly question: Where is MAP sensor located in DF40A? Can't find this piece in schemes...

[bbzuki]

This thread is focused on the 40-50-60 series motors, but I will report results from a test I did this past weekend with the DF25A motor I have on my 13-ft aluminum runabout. My boat weighs about 250 lbs empty without the motor. The DF25A and DF30A share a common 3-cylinder platform.

For around $5 I bought the non-restricted version of the air intake "seal" and installed it in my motor yesterday, supposedly converting it from a 25 HP to 30 HP motor. So in theory, I'm comparing performance with a 25 HP motor to performance with a 30 HP motor.

I currently have a 12-pitch, lightly cupped, stainless "Turbo Hot Shot" prop on my motor.

With a co-pilot in the boat (crew = 2 = probably 350 lbs load), we went upstream and downstream about 1/2 mile in the river near my home town. There was a moderate wind blowing downstream, so when we ran upstream we were running against more wind... I don't know the windspeed; it was enough to rough up the water, but not close to whitecaps. First we ran the "stock" motor, then pulled the boat out of the water and swapped from "Restrictor" to "Seal" in the parking lot - took about 15 mins - then re-launched the boat and tested the "30 HP" modification.

In the 25 HP engine configuration:

Upstream WOT we saw 5650 RPM and 26 MPH
Downstream WOT we saw 5750 RPM and 29 MPH

In the 30 HP (?) engine configuration:

Upstream WOT we saw 5750 RPM and 27 MPH
Downstream WOT we saw 5850-5900 RPM and 30 MPH.

When I'm alone in my boat, I hit 5000 RPM on plane from a stop in about 2.5-3 sec. With a second person onboard, it probably takes about 4 sec to reach 5000 RPM on plane. To be honest, I can't say that I felt a significant difference in "hole shot" after installing the 30 HP gasket.

Bottom line: I found about 100-150 RPM and approx 1 MPH difference between the 25 HP vs a 30 HP (I think) motor.

I included photos of the "Restrictor" that sits in the airway of the 25 HP motor, and the "Seal" that sits in the same location in the 30 HP motor, and one of my 3 spark plugs after about 30 mins running around with the "30 HP" motor mod.

New guy here.. hello everyone.
Have you found any more "tweeks " to that df25a?

[pafnuc]

My results with 60 HP silencer holder (4,5 meter RIB): 16" aluminium prop, just me on board: 62 km/h, max RPM 5900. Before with 40 HP holder: 14" alu prop, 52/km/h, max RPM 5800. 30 hours after mod. No overheating, spark plugs looks just the same before and after modification. Hole shot is awesome. After mod running only on hi-octane/premium gasoline (98 octanes).

[mrpister]

Nice results pafnuc. Similar to mine. Enjoy the new power!

[oldphart]

Thanks a lot for the info. I just replaced the silencer holder in my DF40 to the DF60 version. I was able to get to the bolt by wrestling the air filter a bit, and using a 10mm socket on an extender.

Beforehand, the engine would max out at about 5400 rpm and 24 kts, now I get almost 6000 rpm and 27+ kts at WOT. Pretty much perfect. Much more noticeable is the acceleration. What a difference, just ***! The boat jumps up on a plane with a big ROAR, and also holds the speed/plane on marginal speeds much better. Seems to have much better torque.

Great stuff!

[Cell_4815]

I know this thread is a few years old but I wanted to ask if anyone has had any problems with their DF40 from changing the silencer, thanks

[Moonlighter]

No, no issues for ours.

[Realsass]

Rather than switching your 40 silencer for a 60, did anyone just remove the brass plate inside the holder?
would this not also work or achieve the same results?
removing that plate with the holes in it would essentially be removing all restrictions in the silencer. What I am missing here ?
any feedback would be greatly appreciated.
thanks guys!

[Realsass]

Is anyone still following this thread anymore

[Moonlighter]

Yes you could do that.