Idle issue df175 (2400hrs)

[Mikeroo]

We run two 175 (2007) Suzuki engines, great product with approx. 2400 hrs, I am way overdue with replacement of my High and Low pressure Fuel filters (trust me this is not typical) for the most part I am a fanatic!

So we ran the boat last Saturday and my port side engine quit idling while we were catching Rock Cod. Tried to start , no go , pulled the level to total neutral gave it some gas and she fired up right away , decreased RPM to slip her in gear and she quit ,the minute RPM dropped below 1000.

After she fired up she ran great with no signs of any problems, just couldn't get the RPM to the point I could slip her in gear !
I am a new member, first thread, and welcome response and feedback.

[Harper]

Check out and clean up the IAC. And the bypass air passage that the IAC feeds through. Don't go messing with any idle speed thottle settings until you've thoroughly checked the IAC and if you do make any throttle settings for idle make sure you closely follow the procedure as outlined in the service manual. If you don't have a service manual, get one before you attempt any work.
Outside of oil changes and routine filters, etc, have you maintained these motors yourself or had them serviced at a shop?

[Mikeroo]

Thanks fpr the come back and pointers apart from balancer chain replacements by Dealer at 2000 Hours (which they didn't need) factory recommended 1,600 hrs. Touch wood they have performed beautifully with routine replacement of oils, water pump impellors, spark plugs etc. Is there something we should have done, neglected to do??. Trust me I am a believer in prevention is better than cure

[Harper]

I don't think there's anything you've neglected to do. You didn't mention check/adjust valve clearances. Every 200 hours.
The IAC can crud up sometimes, may be getting a little sticky. Might be corrosion or something on the connector, though I think anything like that would trigger a fault. Also the idle air passage might have something partially blocking it. Those are just the first things I'd look at.
That it runs good at open throttle and under load, is the reason I'm suggesting the IAC. At idle, the throttle plate is very nearly closed, and the idle speed is controlled by the ECM via the IAC.
You've gotten some good service out of those motors, You must be doing something right.

[Mikeroo]

Totally appreciate your advise ,we will check it out, believe me and provide you with feedback, as for the valve clearances , not on my recommended maintenance checks from Suzuki, plus it sounds like it is way over my head!

[Mikeroo]

We will be removing the component and proceed with checking and cleaning , any direction on this process?? Harper you come across like someone who work and or have had experience with these motors, One item I need to mention I never had a warning light or indication come on in the tach gauges.
Again thanks for the support
Mike

[Moonlighter]

See my posts on the thread linked below re anti-syphon valve on fuel tank. Could be the issue. At idle revs a bad/sticking valve doesnt let enough fuel thru so engine stalls. But the engine overcomes the valves resistance at higher revs and runs fine.

http://www.suzukioutboardforum.com/s...alls-idle.html

IAC problems will usually result in high erratic revving when engine is started. Wont hurt to clean it out but not sure this will be the issue.

Elimintaing the anti syphon valve is easy and inexpensive, with no downside even if it is not the problem. They do fail quite regularly though from what ive heard.

We just unscrewed it from the tank, punched the ball, spring and seat out from inside it at the workbench, reinstalled the now empty barb fitting to the tank and reconnected hoses. Done.

[Harper]

Here's the procedure from my manual for checking the IAC.
Also follow Moonlighter's suggestion. That's also a possibility.
And you really should check your valve clearance. It's supposed to be checked every 200 hours or 12 months. Some people have found zero clearance on the first 200 hours inspection. If left that way, it will result in a burned valve, especially on an exhaust valve. Mine were all too tight on the intake valves, but the exhaust valves were fine. I believe that the largest variance from correct clearance is going to show up on the first 200 hour. After that, the change in clearances should be minimal.
Again.....you've got 2400 hours....you're doing good.

[Mikeroo]

Just want to again say thanks to Harper and Moonlighter for quality feedback and support , we found a faulty I A C , component, (expensive little pups ) does help to shop the Net

[tudunka]

Hi All,

I just picked up on this and I seem to be having the similar issues. I have a 2006 DF 175 that will not idle, I have to throttle up, and it is NOT throwing any codes.

i pulled the IAC out (that was a bitch to do, sits just under the starter gear plate that sits on top of crankcase), but I don’t understand how do you clean it. I saw a YouTube video that showed some guy unscrewing it and taking it down to parts. Is that what you have to do?

Also, if I put a new one in or put the cleaned up one back in, leaning more to just replacing, is there some electronic key On/Off sequence you have to do so the computer electronics sync up?

thank you for any and all assistance!!!!

Andy