New member and new Suzuki owner DF40A

[pafnuc]

mrpister could you post photo with df 40 and df50 silence holders? What mark is on 40 and 50? N1 or N2? I want to compare size of holes on them. Thanks.

[allycat]

I have a 2003 DF40 and have been waiting for MrPrister to update his findings. Well, I got a little impatient and decided to open up my restrictor holes to approximate the 50 restrictor. I pulled the silencer and surprise, no restrictor in place. I'm guessing the prior owner of the boat had already pulled it. I have no way of comparing the before and after performance, but have been running the boat for the past 5 years with no issues whatsoever. Plugs look good and the motor performs well. He did upgrade to a larger stainless prop, RPM tops out at 6000+-. If I get motivated, I may put the original prop back on for comparison purposes. Will post results here when/if I do.

Just check the throttle opening of the earlier model as I am told the first restriction is the cam that operates the butterfly which needs to be changed to allow the throttle to open all the way, the next mod is the ecu. These are the mods I was told about for my DF 40 A before the mechanic realized that mine was the later model!!

[allycat]

Sorry for the delay. I received the SDS tool, but have not had a chance to hook it up. Work has me very busy.

Rest assured, as soon as I have more information, I will post any news.

mrpister, have you made any headway on your testing yet?

[2014DF25ARS]

Yesterday afternoon I removed the air cleaner box from my DF25A engine. (I was following the Service Manual instructions to access the water cooling thermostat, but eventually decided I didn't need to remove everything stated in the manual.)

When I removed the air cleaner box, I had a good view of what I believe is the "air restrictor plate" that's being discussed in this thread. Member mmanuel posted a photo earlier in this thread of the air intake on his DF30A engine. My DF25A is based on the same platform as the DF30A. I'm posting a photo here of the "Restrictor Plate" I find on my DF25A motor, and a diagram from the Service Manual showing a parts breakdown.

Edit: Oops; after posting the parts breakdown, I see that the website apparently shrunk my image till it's unreadable. In the reference block at the bottom of the diagram, the part (8), which I circled in red on the diagram and show in the photo below, is described as:

Seal (DF30A)
Restrictor (DF25A)

[Pot Hole]

mrpister, have you made any headway on your testing yet?

Bump. I'm interested as well.

[mrpister]

mrpister, have you made any headway on your testing yet?

Sorry folks. Work and family issues have come first. I hope to hook up the SDS tool this weekend to check the temp logs. I won't be able to try the 60 hp silencer holder until next spring. But I will report the temp readings recorded running the 50 silencer holder as soon as I pull them.

Thanks for your patience.

[mrpister]

Finally had a chance to hook up the SDS. No overheat readings were recorded. No alarms at all except over rev. Plug is pretty white but a Suzuki tech says it is ok. So next spring I will try the 60 hp silencer holder.

And I will post a photo of all the silencer holders side by side in a few days.

[Moonlighter]

Thanks for the update!

Having investigated further with knowledgeable sources, I have decided to fit the silencer holder from the 50 to our 40A. May even go the whole way and use the 60.

No-one has reported adverse issues - of course warranty would likely be compromised if any related fault happened so take that into account before you decide what to do.

Cheers!

[mrpister]

Thanks for the update!

Having investigated further with knowledgeable sources, I have decided to fit the silencer holder from the 50 to our 40A. May even go the whole way and use the 60.

No-one has reported adverse issues - of course warranty would likely be compromised if any related fault happened so take that into account before you decide what to do.

Cheers!

My pleasure! I look forward to your feedback on the 50hp holder.

I could immediately tell the difference when I installed it.

And I am anxious to try the 60 holder but there is no opportunity for me to do so until the spring here in Canada. The water here will be very hard soon (frozen)

As I promised, a picture with all silencer holders side by side is forthcoming.

[Moonlighter]

Thanks! Look forward to seeing the pics!

Did you get my PM?

It appears the part # for the silencer holder on the 40 and 50 are the same, when I do the parts lookup on this forum's link.... which doesn't seem right.

Do you know if that is correct? Can you advise the part # for the 50 silencer holder that you got?

Thanks!

[mrpister]

40 hp ---------- 13820-88L00

50 hp ---------- 13820-88L10

60 hp ---------- 13813-88L00

[mrpister]

Photo of all three holders side by side attached.

Hole sizes (approx.):

40 = 8mm

50 = 11mm

60 = 57mm

I am not good at math, but it would be interesting to know the percentage airflow gain with the 50 and 60 holders.

[pafnuc]

Thanks for the photo mrpister.

[pafnuc]

I am not good at math too, so mistake is possible.
My calculations:
8 mm hole = surface of approx. 50 square millimeters x 4 holes = 200 sq. mm.
11 mm hole = surface of approx. 95 square millimeters x 4 holes = 380 sq. mm
DF60 one (big) hole = 2550 sq. mm.

[mrpister]

Thanks pafnuc.

When I see that the 60 holder will provide more than 10x the airflow of the 40, that worries me that the ECU on the 40 won't be able to cope.

I guess there is only one way to find out. But I have to wait until spring here in beautiful Canada.

I should also point out, there are three small holes in the rubber section of the 40 and 50 holders which you can see if you look closely at the picture.