Mods to beef up 25hp motor?

[ndthwacker]

I have a 92 suzuki dt25, its a tripe. from what i have been reading this motor is pretty much a toned down 30. Anyone know some of the simple things i could do to give it a few more. I really dont want to start porting or shaving heads, a few more hps is not worth that to me. i was more wondring about carb work, would a dt30 or 40 carbs or just jets and needles fit a 25? Also would a cmc power trim give me a few more mph on my top end? and any idea and what pitch prop would help out top end? thanks for the help

 

[99yam40]

Re: Mods to beef up 25hp motor?

You can look up part #s for your motor and a 30 of the same year to see what all parts are different

 

[JB]

Re: Mods to beef up 25hp motor?

If what you want is more speed you will get more improvement by fine tuning prop selection, weight and balance of the boat, and rigging of the outboard than you can get by turning your outboard into a bomb with a short fuse.

First, is trim and height of the outboard. Power trim and ability to adjust height will add at least 10% to your WOT speed Once you learn how to optimize both under weigh. No engine mod can approach that sort of boost. A tilt and jack plate isn't cheap.

Next is the perfect prop for that rig; one that will allow the top of the operating range. SS props have less drag. Two blades give the least drag, 4 blades give the best "traction" on take off, 3 blades are the best all-round. Real fine tuning fanatics have different props for different loads.

Good luck, and let us know what you do.

 

[ndthwacker]

Re: Mods to beef up 25hp motor?

i read that you can change out the throttle linkage and removed the throttle linkage stop on the middle carb (basically to turn it into a 30hp) i googled for the modification and on one post i guy did this. any opinions on if that would be a good idea or help at all?

 

[HankZuki]

Re: Mods to beef up 25hp motor?

I have heard that the linkage to the carbs specifically the stop on the middle carb does help, even more so than putting the bigger jets from the 30. I have a 93 and its not a quick fix like on the 92 and earlier. I did have a reply to the same question. I posted it on another site similiar to this one and got a pretty good suggestive reply from someone that went through it down in Florida.
I'll try and find that thread and pass it on to you. I'm about to start tweeking my 93 and just reworking the carbs right now. I do intend to get the rev limiter taken out and lightening the boat. Will put it on a wet bike eventually. Porting it, trimming only .75inch off the short pipe ( no more no less ) was suggested tried and trued. A 14' slightly cupped SS prop was putting their experiment tunel hull up to 75 mph. think they were running alcohol as well. Oh he also suggested taking out the oil pump and mixing the oil in the gas tank that was more or less to shed weight.
On the porting issue; he was saying that that little motor sounded like a 1.5 litre sitting there when idling. A friend of mine suggested I port it below the cavitation plate so that its not so loud while idling around in public places. When you open it up it will scream pretty loud.

L8R
HANK