Home Made Speedster Silencer

[To2d]

Here is an easy and clean way to lower the engine noise in a 2 stroke Boat!

This is on my 99 Seadoo speedster SK but would work on many other Seadoo boats
Always measure first! You might need to change the size of some of the parts below.

"Ingrediants"
1. 2 1/2 inch PVC LB
2. 3 inch PVC TA "i know 1 and 2 are two different sizes ** "
3. PVC cement
4. 3 inch lock nut
5. Peel and seal "get the U-Seal from home depot. its thicker then the one at Lowes"
6. White spray paint
** The reason for the two sizes is to make the opening match the air exhaust hole in the boat and fit the space in the hull

Install

1. Attach the 3in TA (2) over the in let of the 2 1/2 LB (1) with the Cement (3) and let set.
2. Open the 2 1/2 PVC LB (1) and line both the lid and the inside body with the peel and seal (5)

3. The LB (1) should be lined along with both holes

4. Paint the LB (1) to match the boat "this is just to make it look factory in the engine bay"

5. Remove the air exhaust port cover from the boat
6. Move around wire harness and insert your new silencer into place up through the hole and start lock nut (4)

7. Turn your new Silencer clockwise until it hits the hull of the boat
8. Carefully tighten the lock nut (4) until it is firmly in place. "i used a punch and rubber mallet and made little taps" and re-install air exhaust port cover


Enjoy the look

And more importantly enjoy LESS NOISE!!!
This is a before and after Db test taken out of water with both engine running. Sound meter set to max hold/slow for the best results. These numbers are the highs at 2,500 RPM


6db difference is a big deal! But seeing it out of water. WOW

Hope this helps

 

[snikwad003]

Nice work man. Looking forward to a water report

 

[whitewheels]

This is nice stuff. Good write up

 

[To2d]

Water Report: Out on the water today for the first time since I installed the homemade silencer. It worked! At idle it was much quieter in the boat and even at speed I could hear the music clear. I was sitting at The launch waiting with it idling and you could barely tell I had two 2 strokes behind me. Wife loved it!!!

 

[justinsrad98]

Where did you buy that lb box? The only one I can find are 2 inches box. I did 3 hardware stores today.

 

[To2d]

Platt electric supply or any electrical distribution house should have it.

 

[justinsrad98]

I was able to find the box at an electrical store. I decided to make some separator inside.

I'm not good at wrapping !

 

[To2d]

I was able to find the box at an electrical store. I decided to make some separator inside.

I'm not good at wrapping !

Looks good! What size LB is that?

Let me know when you do a water test and how it worked. (Do you have a sound meter?)

 

[justinsrad98]

I don't have a sound meter. Same box as yours. I will do a water test this week end.

 

[Ankeneyou]

You can download an app on your phone to get some idea. I'm sure it's not real accurate bit will give some way to gauge the change.

 

[justinsrad98]

You can download an app on your phone to get some idea. I'm sure it's not real accurate bit will give some way to gauge the change.

Downloaded

 

[justinsrad98]

It was a little bit quieter than usual but not by much

 

[To2d]

Is that 84.6 on the water?

 

[justinsrad98]

Yes but there was a lot of wind

 

[trdehmer]

Just so I'm clear, this is installed in the vacant hole opposite the side of the blower vent hose exit? On my 1998 Sportster this would be on the left/passengers side above battery.

Could a person do something similar for the blower vent - maybe an insulated hose for that too?

In the attached photo 5, 6, 8, 17, 28 make up the vents in my Sportster - the one on the left/passengers side above the battery would be the intake, and the one on the right/drivers side would be where the blower hose/fan is hooked into.

Justin, did you feel it worked well for you as well?

 

[To2d]

Yes... you install this in the vacant hole. I did this on a speedster with the engines farther back from the driver and passengers BUT I did the sound tests from right next to the vacant vent. That is were most of the “in water” idle noise comes from.

Here is a test for your boat. While idling stuff a couple towels to block both the vent and free hole for a quick moment. “Quick so your engine can get back to breathing.” Make sure the engine bay cover is closed and engine storage shelf is in just like it would be on the water.

Listen to both sides near the holes and from the drivers seat.

That test will show you if a damper would help you or be a waste.

 

[trdehmer]

When you say block the vent and free hole, are you saying the vent is the blower?

 

[Chester]

While I do understand it's nice to reduce the noise, is it worth it to impede a safety feature? That cover above the hole is easily ripped off with your hand so you can spray your fire extinguisher through the hole into the engine compartment. In case of an engine fire.

Chester

 

[To2d]

When you say block the vent and free hole, are you saying the vent is the blower?

Yes but just for a min to see to the volume change.

 

[To2d]

While I do understand it's nice to reduce the noise, is it worth it to impede a safety feature? That cover above the hole is easily ripped off with your hand so you can spray your fire extinguisher through the hole into the engine compartment. In case of an engine fire.

Chester

Interesting...I never thought of those covers as a “safety feature”.

Couldn’t I open the back and spray if I had a fire. (Knock on wood).

I would have to open it anyways to get to that cover above the hole

 

[trdehmer]

To2d, did you make/use the "silencer" for your blower hose as well? Or did you just make the blower hose have a 'U' in it somewhere and wrap some insulation around it?

 

[Chester]

Interesting...I never thought of those covers as a “safety feature”.

Couldn’t I open the back and spray if I had a fire. (Knock on wood).

I would have to open it anyways to get to that cover above the hole

Yes you could but if you do, you introduce a lot of fresh air (oxygen) that may cause a huge flare up.

Chester

 

[mikidymac]

You could always install the actual correct part.....

 

[To2d]

There you go Chester. Add this small fire hole and your good. Only 2.7 inch hole and works for what your talking about. Better then the rip and spray.

My wife takes the boat out a lot and I don’t think she could rip that vent cover off if she wanted to. Not a great safely feature if everyone can’t use it.

Thanks Mikidymac

 

[trdehmer]

Just need to keep in mind the open vent hole on one side is there for a reason, to feed the engines air...