Suzuki DF70-Low RPM-Prop Question

[Brainburn]

Hello All,

As per JB's advice I have re-posted my question here.



Information:
-2006 DF70
-approx 50hrs
-has 20 hr service (absolutely anal about break in period)

Fuel tank vents are opened.

The problem:

I picked the boat up, MacGregor 26M, and started the break in period but never exceeded 5200 rpm-ever. 5200 was the max rpm I could get out of the engine at the time and I figured it was due to break in period and didnt want to push it.
Since then my fuel efficiency has gone to crap and I cant get anything over 4800 RPm with a good tail wind and both my wife and kid paddling 8)

I have adjusted the throttle linkage (almost to the end of the threaded portion) and the only result was to increase the idle to the point it would SLAM into reverse. I have since backed it down to it's original length.

My next step is to check the fuel system specifically the filters to check my flow.

I checked the specs and it has an operating range of 5200-5800 rpm. I am no where near it now.

Any and all help would be appreciated.

Thanks all,
Mike

***
His response

"I suspect that you are over propped. That will lug the engine and make it burn too much fuel.

Repost your description above in the Prop Forum for advice on how to optimize your DF-70 performance with a better prop pitch. Tell them what I told you here."

 

[walleyehed]

Re: Suzuki DF70-Low RPM-Prop Question

I ran into this same issue with a DF115....we were at 5200 (Max rated 6000) and I made the mistake of going from a 17P to a 13P...I was thinking of the general rule of 200RPM per inch....that don't work on a 4-stroke that's in the low range to begin with...I installed the 13P and it hit the rev-limiter of I believe 6200...I bought a second prop in 15P and it put the R's RIGHT at 6000 with a normal load.
Now, if that is a dealer set-up, I believe it's supposed to go back to the dealer at 25hrs for service check, at that point I would explain the RPM issues...I went through HE double L working with the dealer on the DF115 because I told them (300miles away) that this prop would not work at our altitude...they said I was nuts, and said if the prop installed did not get atleast 5800 with normal weight, they'd replace the prop...well, they backed out because they wanted the boat back to see what the trouble was and the owner said no, I'll take it to another zuki dealer alot closer. I changed the prop and when we got the correct RPM, the owner went to the closer dealer and agreed totally that the dealer that set it up had no clue what they were doing and offered to call them. He got them convinced that 3200ft more elevation DOES make a difference...they paid me for the prop.
sorry for the long story...what I'm getting at is your dealer needs to get it set up correctly, and now dropping 400RPM from initial break-in scares me...I think it best for you to contact your dealer...I'm sure there is a service time at 25hrs when new.

 

[Brainburn]

Re: Suzuki DF70-Low RPM-Prop Question

I will call them tomorrow as they are closed on Mondays.
I have already had it serviced at 20hrs with an authorized dealer nearer to me. It isnt that the original dealer is too far away it is just I have have to tow my 26 footer through Seattle traffic to do it. ugh:%

The information makes perfect sense. Thank you.

 

[achappell.mbs]

Re: Suzuki DF70-Low RPM-Prop Question

I ran into similar troubles. I had my mechanic send my injectors to Flagship Marine to be cleaned. Fuel flow was doubled, rpm's increased, runs great.