Suzuki DT25 ('88) WOT? Need for new prop

[gsk2005uk]

Hi there,

As I am going through fixing/restoring my boat I thought it would be a good time to get a new prop as the old one has had its days!

I was entertaining the idea of changing the prop's pitch etc but I have no idea what my engine's WOT(wide open throttle)max rpm range is. How do I go about finding it?

By the way I got a Suzuki DT25 ('88) (Model No:02503-xxx...)

 

[Silvertip]

Re: Suzuki DT25 ('88) WOT? Need for new prop

Do you have a tach? Did you check the ID plate on the motor? It is usually listed on it. It is probably in the 5000 - 5500 RPM range. But that does you no good anyway unless you have a tach so you know what the engine is actually turning at WOT.

 

[gsk2005uk]

Re: Suzuki DT25 ('88) WOT? Need for new prop

Do you have a tach? Did you check the ID plate on the motor? It is usually listed on it. It is probably in the 5000 - 5500 RPM range. But that does you no good anyway unless you have a tach so you know what the engine is actually turning at WOT.

The ID plate just tells me the type and model number of the motor. Unless there is a way (unknown to me) to derive the engine details from the model number. I have no spec sheet/manual, which is quite annoying

You are suggesting to use a tach to find it experimentally? I guess it a good excuse for me to make a panel with dials for the boat!

Thanks for the info

 

[steelespike]

Re: Suzuki DT25 ('88) WOT? Need for new prop

You may be able to get your prop repaired so it is in good shape for testing.
You could get a tiny tach easy to hook up can be used on any motor of similar design to yours without regard to poles.reasonable price check the internet for tinytach site.Get the max rpm and speed.While your testing fine tune the motor setup especially the verticle height.Start with the anti vent plate(just above the prop) about even with the bottom of the boat.Raise the motor to just before venting becomes a problem.Be sure clamp
has a good grip and it pumps water.Also fine tune the trim.Once your all set
the final max rpm and speed will help us decide a prop choice.A cupped or stainless prop could give even more height and speed.Speed gain could be a couple of mph before the prop change depending on where your at now.
Don't make any prop changes without max rpm and speed info.

 

[Silvertip]

Re: Suzuki DT25 ('88) WOT? Need for new prop

The reason we need WOT rpm is if the engine does not reach the upper end of the WOT rpm band, the engine is considered over propped (too much pitch). If it over revs it has too little pitch. Of course the engine needs to be properly tuned and must not be worn out or otherwise down on power because all the prop swaps available can't fix that problem.

 

[gsk2005uk]

Re: Suzuki DT25 ('88) WOT? Need for new prop

You may be able to get your prop repaired so it is in good shape for testing.

Well my prop touched down on rocks and the tip of one of the fins has a bit missing! The missing bit, if I remember correctly is about 1 x 1/4 inch. The other two fins are a bit rough at the edges but still in one piece. I haven't "felt" any significant downgrade in performance but it drives me nuts seeing it like this.

Do you think this (aluminum) prop can be repaired and what would it cost me?

As for the tach, I think I should attempt to make a dial panel. I have been meaning to make one for quite a while now along with some sort of a switch board for lights, engine etc Not sure if its worth doing so many repairs/upgrades on an old boat but I feel that its an opportunity to learn a lot!

Cheers for the advice, will keep you updated on the WOT as soon as I install the tach.

 

[BF]

Re: Suzuki DT25 ('88) WOT? Need for new prop

yes your prop could be fixed to be (and look) as good as new. Price will depend where you are and where you take it. I'm guessin' my "prop guy" would charge $40 to repair yours... Seems if "it's not too bad" it's $40... if it's worse, it'll be more like $50 or $60

out of balance props are tough on lower units... if you want to repitch, get this one fixed up anyway.