1985 Suzuki DT115 Max RPM Question

[evinrude20]

Hey there, I have a 1985 Suzuki DT115. I typically run it around 2500-3000 RPM. When I go WO, it maxes at 3500RPM. Is this normal? I have heard that they should be running around 5000rpm. Any suggestions? Thanks alot,

Dan

 

[deejaycee_2000]

Re: 1985 Suzuki DT115 Max RPM Question

What prop are you running?

 

[evinrude20]

Re: 1985 Suzuki DT115 Max RPM Question

Not 100% sure, but I think its a 13" 22-24 pitch? It's the one that came with it, it seems to be a bigger pitch.

 

[evinrude20]

Re: 1985 Suzuki DT115 Max RPM Question

I was also wondering if it would be possible that it isnt running on all cylinders. I had that happen before where it maxed out at around 2300rpm, brought it in to the shop and it wasnt firing on all fours. And a side note, When I start it up, at low idle, it "pops" every now and then until, it gets warmed up. not a loud bang, but i had it running out of the weater today and I could notice it more. It's like a quick blast out of the prop. Once its warmed up, or rpms are incrreased, it goes away. Sorry for the long post, but I'm troubled!@!!
Thanks again,

Dan

 

[bowhuntrrl]

Re: 1985 Suzuki DT115 Max RPM Question

Not 100% sure, but I think its a 13" 22-24 pitch? It's the one that came with it, it seems to be a bigger pitch.

What size boat?? That prop size/pitch sounds way off unless it's on a 14' boat.

 

[evinrude20]

Re: 1985 Suzuki DT115 Max RPM Question

I may be off on the 13", going from memory, it is a big prop, would 18" sound more correct? IT's an old 19.5' wooden boat. I had it running last year and it maxed around 4200-4500 rpm.

 

[James R]

Re: 1985 Suzuki DT115 Max RPM Question

To check for your prop size go to brownspoint.com and go to parts an click on props. Normal peak revs for this motor is around 5500.

 

[bowhuntrrl]

Re: 1985 Suzuki DT115 Max RPM Question

First thing that you need to do is find out what pitch that you have and we can go from there. I have a DT-85 on a fiberglass 16' center console. My original prop was a 13 1/4x19 Pitch Suzuki prop.. The boat would not pull max rpm, in fact it wouldn't even plane unless I walked around and stood in front of the console. I'm currently running a 13 1/2 x 15 pitch and she pulls 5500 rpm and 34 mph. That DT-115 is just a bit more powerful than my DT-85 and your boat is very heavy. I would suspect that the same prop as mine will work much better for you. I think a 19 or 22 pitch prop is totally wrong for your boat.

 

[DadTo2Marines]

Re: 1985 Suzuki DT115 Max RPM Question

The popping noise is a clue to your overall problem. I'll wager a donut that you can get all kinds of RPMS through the fast idle. It sounds like you need the carbs rebuilt. Rebuild the carbs and if you still have the problem test the fuel pump(s)

 

[evinrude20]

Re: 1985 Suzuki DT115 Max RPM Question

Is there anyway of knowing which carbeurator is the bad one? It was in the shop a few years ago (3 or 4) and got all cleaned up. I ran some carb cleaner through it 2 days ago. And yes it does get full rpm at idle. AS far as the prop, it is a 13 X 19". I'll have to look into getting a smaller pitch.