Suzuki DT100 Specs - Help the NuBe

[walkingfish]

Hi Guys,

I live in New Zealand, so the time difference might be a bit out.

It's summer here, and i just bought a ski boat, with a DT 100 on the back.

I suspect the the guy I bought it off was a bit "eccentric" and hs made what could loosely be called "modifications" that i would like to undo!

The main 2 are as follows,

1} Holes have been drilled through the leg, just above the cavitation plate, and into the exhaust cavity, of course as soon as your planing, all the exhaust is vented above the water line, very noisely!

2} I think the rev counter setting ( its a Suzuki branded one ) has been changed to make it look more impressive, as i can pin the rev counter at 8000 rpm with ease.


So, other than making noise, is there any reason to vent exhaust above water ( eg less back pressure )??

What setting 4 / 6 / 8 should my rev counter be on, and what is the maximum revs i should be pulling.??

Many thanks in advance.
Brad

 

[bossee]

Re: Suzuki DT100 Specs - Help the NuBe

Hi,

5750 RPM at full throttle.

Where exactly are the drilled holes?
Check the images below and try to tell us where the holes are.
Maybe some parts lists picture can help You some also:
http://store.brownspoint.com/dt100.asp

Tachometer should be set to 6P (12 poles).
http://www.downloadingfiles.co.uk/t...structionmanuals/99320 rev 10 Tachometer,.pdf

/Bo

 

[walkingfish]

Re: Suzuki DT100 Specs - Help the NuBe

WoW, thanks Bossee for the speedy response!

I will make gthe change to the pole setting on the rev counter, that should stop it looking like its pulling 8000 rpm!

As for the extra exhaust holes, there are 4 x 1/2 inch holes on each side of the lower leg / gearbox. They are drilled in a line, parallel to the cavitation plate, and they are as high up the gearbox as you can get. The "1" in the top picture is kind of pointing to the area that they are in. It's between the 2nd and 3rd bolts (fron the bow) that hold the unit on to the midsection.

It's nice and quiet while idling, but real loud (sounds MEAN) when planning, i would like to fill them in if they are only there for the sound!

Any thoughts on how to fill the holes, how hot do they get, why would someone do this to a motor, or is it like the kids with there oversize exhausts on their cars? lol

Cheers,
Brad

 

[bossee]

Re: Suzuki DT100 Specs - Help the NuBe

Hi,

As I understand what you described it is 4 holes like this on each side of gearcase.
Is this correct? If yes, I would probably let some with knowledge weld the holes and then grind it smooth on outside. Some primer and then Suzuki paint and finally some layers of clear lacquer.

/Bo

 

[walkingfish]

Re: Suzuki DT100 Specs - Help the NuBe

Hi Bossee,

I'm glad you couuld decipher my explanation, that is exactly where the holes are.

Apart from being noisy, could they also lead to cavitation?

Thanks
Brad

 

[bossee]

Re: Suzuki DT100 Specs - Help the NuBe

Hi,

Since the holes are above waterline when on plane with the boat it has no bearing on ventilation (cavitation).
Ventilation mean for example the propeller will slip but if you have the outboard properly mounted vertically (not to high) there should be no ventilation problem with the prop.

Most part of exhaust should go out via propeller hub under the water so just weld the holes and it should be quiter.
There are no holes there from the beginning on this DT100 so restore to orginal condition should be just fine. That is what I should do.

/Bo