2006 DF70 unable to hit max rpm's, is this a issue?

[1poway]

Hi Forum Members,
My 2006 DF70 with 250 hrs is supposed to hit 5800 rpm's. 18' Center Console 1500 lbs, and motor will only allow 5200 rpm. This is the lower limit of the allowed rpm operating range. I do not wish to damage the motor by lugging it.

Do I have a problem? I would prefer not spending money on a new prop if I'm good to go.

Thank you for any wisdom!

[barrell]

Yes, Suzukis love being at the top of the rpms range. Are you sure thats not 6200? First you need to get engine height correct and then play with props. Do you know the temperature it runs at when wide open? What prop is on it now?

[1poway]

Yes, Suzukis love being at the top of the rpms range. Are you sure thats not 6200? First you need to get engine height correct and then play with props. Do you know the temperature it runs at when wide open? What prop is on it now?

Thanks Barrell,
I'm not with the outboard currently, But:
A) I'm 99.9% sure normal operating range is 5200-5800 rpm on this 2006 DF70.
B) Brand new Suzuki Thermostat installed.
C) No independent temp gauge other than the thermostat, that I'm aware of.
D) Outboard height is good referencing the wisdom in this forum.

[Moonlighter]

At 5200rpm you are lugging, and the engine will also not be giving you its best performance or economy. I would venture that your acceleration out of the hole would be sluggish as well.

If you get the height and prop set up correctly, you will find that the engine/boat performs so much better! You will really notice the difference!

See the "sticky" thread in the top section of this forum that talks about how to set engine hieght and select props. Set the engine height up first, then change prop pitch if necessary.

[1poway]

Thank you Moonlighter

[redlowrey]

Hi Forum Members,
My 2006 DF70 with 250 hrs is supposed to hit 5800 rpm's. 18' Center Console 1500 lbs, and motor will only allow 5200 rpm. This is the lower limit of the allowed rpm operating range. I do not wish to damage the motor by lugging it.

Do I have a problem? I would prefer not spending money on a new prop if I'm good to go.

Thank you for any wisdom!

'''' That is a fair bit of boat for a tiny motor, my boat is twenty feet and around two hundred kg more with a df 140 on the back.

[Moonlighter]

'''' That is a fair bit of boat for a tiny motor, my boat is twenty feet and around two hundred kg more with a df 140 on the back.

I agree Red! I didnt read closely enough - a 70 on an 18 ft centre console, even a lightweight one, is going to be working REALLY hard. Possible exception being a panga style hull??

My 18ft (5.5m) Surtees plate alloy boat runs max hp which is 115, min hp recommended is 90. A 70 would be sloooooow.....and struggling.

I suppose that in any case, it will still need to be propped lower by a couple of inches to get revs up towards the top end of the recommended range to perform as good as it can, in the circumstances - would you agree?

[redlowrey]

For sure, I never run mine over 4200rpm, every now and then I will give it a squirt to six then drop back down to 4200, it seems to be a sweet spot with mine, I get around 2.3 klm to the litre at those revs and a round trip for me is around 75klm, I am running a 3x14x21in prop.

[1poway]

Here's my boat she weighs 1100lbs, without fuel and people. 50-90 hp recommended.

Seaway

And thank you, for the wisdom!!