Suzuki DF115 idle adjustment?

[Paul Beaurain]

Hi

Suzuki DF115 4 stroke

The idle speed has progressively dropped to 500 rpm. the recommended is 650ish. Can I do this and if so how?

The engine was serviced in Feb, and has done 20Hrs since. It now stalls on occassions when engaging gear. the owners book doesnt cover this.

thanks in advance for some assistance

Paul

[gavin]

Have a look with the hood off, at where the throttle position sensor sits, rock the control stick foreward and back, you will see where the TPS throtle position sensor moves, where the sensor is mounted, you may, by slightly moving it in its mountings, advance or retard the revs, slack off the sensor mounting screws to give it the minute movement needed, and when you are happy with the idle, tighten the screws up without sensor moving off its new position.

[Neil R]

The engine has something called Intake Air Control which supposedly stablisises idling speed. You need to take this out of the loop first before setting the 'underlying' idle speed using the bypass air screw (which is hidden under a plastic cap - get back to me if you need a piccie).

Engine warmed up and throttle closed. Using the bypass screw raise revs to >1000 for >10 secs. This will set the IAC system to a fixed value, and set off the caution buzzer - 0.5 sec tone every 3 seconds, for 5 mins. Set the idle speed during this time to 625 plus minu 25 rpm using the bypass bleed screw. Cancel this IAC mode by opening the throttle else use the warm up lever. Check idle stabilises at desired value. (If it doesn't then the manual suggests the IAC is at fault).

Not tried this myself - Service manual (covering DF90/115/140) bought recently from Brownspoint Marine! - looks a comprehensive book.

[Paul Beaurain]

Neil

Thank you for posting the detail from the manual.
I will have an opportunity, this week, to look at the engine again.

I think long term I should buy the full service manual - can you recall how much it was?

THanks
Paul

[Neil R]

My bank statement says £55.99. This being the total including the shipping from the USA, the latter obviously making up a reasonable percentage. That was about 1 month ago. To be honest I didn't do much shopping around.

Now all I need is the plethora of special tools and the diagnostic download thingy ...