# Suzuki df30a wont idle or run above 3k RPM



## t1ightl1ines (Mar 5, 2016)

My 2016 Suzuki df30a wont idle and wont run above 3k rpm at around 2500-3k the boat sounds perfectly smooth (7 mph speed). I drained the fuel water separator and it was full of a clear white sand like sediment, I replaced the separator filter and inline fuel filter. I also notice the motor gets extremely hot but pees a solid fast stream of water.

I also pulled the spark plugs and noticed a lot of black carbon build up and they were just changed in January. My fuel consumption was also really bad when I traveled home 8 miles at 2500 rpms.

I tried emptying the tank and putting fresh new gas with some seafoam with no luck.

Should I try cleaning the fuel injector next or what do you guys recommend?


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## lemaymiami (Feb 9, 2007)

Get to a Suzuki tech and find out what's actually going on... This is from a guy who has to have a motor working properly at all times... Seriously, sounds like your motor is in "SAFE" mode (or whatever the Suzuki equivalent is...) since something is seriously wrong... and needs repair...


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## Saltylizard (7 mo ago)

It sounds like you’re going into limp mode. This article might help, he found that a faulty battery switch was giving his ECU wrong data; leading to limp mode. 

With your fuel issues this might not be the case but it’s certainly worth looking into. There is a very small fuel filter buried inside the vst which might be clogged. Some people have said that with this filter clogged the high pressure fuel pump can starve for fuel and put the motor into limp mode. The white sludge you had in the filters is most likely from water in the fuel, I’ve seen parts of Suzuki’s fuel system completely clogged/disintegrated from corrosion. 

If you suspect the motor is running hot, check the thermostat. Pull it from the engine and sure it’s actually opening by dropping it in boiling water. If it’s peeing fine, your impeller is likely okay.

All this being said, I’m not a mechanic. Best of luck fixing your issue.


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## t1ightl1ines (Mar 5, 2016)

I also had a 2-4 CMP sensor code and it was not the sensor that failed. My suzuki Mechanic said the problem ended up being something with the bolt on the cam shaft being loose which im sure is from my stainless prop and all the chatter it makes at low RPMS. Just a heads up to anyone with prop chatter on a stainless prop. It will end up loosening internal parts! This was after 6 years of use but still not worth the extra 1mph.


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## scissorhands (Apr 8, 2012)

did you try a different tank? fuel lines? fuel bulb?


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## t1ightl1ines (Mar 5, 2016)

Yea it felt like a fuel issue but it was the issue I stated above. The CMP code was not allowing the ignition system to give spark.


scissorhands said:


> did you try a different tank? fuel lines? fuel bulb?


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## Mondo Gumbo (11 mo ago)

I have a 2018 Suzuki, and had a similar experience a few months ago. Pulled the spark plugs, and they were covered with carbon as well. Changed them out, and all is well. Don’t know why, motor has less than 100 hours on it. It fixed my “limp mode” condition, worth a shot on yours? Plugs were not oil covered, just carbon. Hope this may help.


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## eberin (Jul 11, 2018)

t1ightl1ines said:


> My 2016 Suzuki df30a wont idle and wont run above 3k rpm at around 2500-3k the boat sounds perfectly smooth (7 mph speed). I drained the fuel water separator and it was full of a clear white sand like sediment, I replaced the separator filter and inline fuel filter. I also notice the motor gets extremely hot but pees a solid fast stream of water.
> 
> I also pulled the spark plugs and noticed a lot of black carbon build up and they were just changed in January. My fuel consumption was also really bad when I traveled home 8 miles at 2500 rpms.
> 
> ...


i recently purchased a new DF30A and I did buy the service manual for reference on items

the owner manual states say when you start the motor it should pee immediately which means to me the tell tale water we see doesn’t go through the thermostat

and the below schematic agrees


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## Willitaylor (11 mo ago)

Check out my post on Aug.10 regarding Suzuki 
outboard running poorly. Might help


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## t1ightl1ines (Mar 5, 2016)

Turned out the stainless prop I was running had a good amount of prop chatter and loosened the cam bolt and threw off the timing which had put the motor in Limp mode. Issue was fixed and I’m back to the factory prop


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## Mike Haydon (Dec 19, 2019)

That is crazy! Now that I heard this I will always check bolts during maintenance!👍


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## Willitaylor (11 mo ago)

I’m feeling pretty dumb right now but what is
prop chatter? Thanks for going easy on me


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## Smackdaddy53 (Dec 31, 2012)

Willitaylor said:


> I’m feeling pretty dumb right now but what is
> prop chatter? Thanks for going easy on me


Vibration at low RPM that most outboards have. I think it’s more of a three cylinder issue than a prop issue.


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## Willitaylor (11 mo ago)

Smackdaddy53 said:


> Vibration at low RPM that most outboards have. I think it’s more of a three cylinder issue than a prop issue.


That’s interesting. I’ve always wondered why the motor sounds like a bucket bolts while idling. I have put in gear while flushing but zero vibrations. Since my pants are down… why would that cause the camshaft to fall out of time? I thought a four cycle would be quieter and vibrate less than a two cycle. Jesus, if bolts on the cam are coming loose should I be checking torque on connecting rod bolts? Rocker arms? Lower gear case? Hell, will the damn thing fall off the back of my boat heading home at night. Is a kicker motor possible on a LT25 Gheenoe? I have questions. BTW Smackdaddy we are pretty close aren’t we. I’m in Fort Myers. Thanks for the info


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## Smackdaddy53 (Dec 31, 2012)

Willitaylor said:


> That’s interesting. I’ve always wondered why the motor sounds like a bucket bolts while idling. I have put in gear while flushing but zero vibrations. Since my pants are down… why would that cause the camshaft to fall out of time? I thought a four cycle would be quieter and vibrate less than a two cycle. Jesus, if bolts on the cam are coming loose should I be checking torque on connecting rod bolts? Rocker arms? Lower gear case? Hell, will the damn thing fall off the back of my boat heading home at night. Is a kicker motor possible on a LT25 Gheenoe? I have questions. BTW Smackdaddy we are pretty close aren’t we. I’m in Fort Myers. Thanks for the info


I think whoever told you the prop caused the powerhead to fail is full of malarkey. 
I’m in Texas, not exactly close but I’ve driven there before.


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## Willitaylor (11 mo ago)

Check out the #10 post regarding “chatter”


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## JC Designs (Apr 5, 2020)

No one even heard of “prop chatter” until 4strokes took over the market. It’s always happened with stainless wheels, we just didn’t hear it before. As @Smackdaddy53, vibration/ harmonics is the likely culprit.


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## Willitaylor (11 mo ago)

Having been a mechanic or technician all my life this has got my interest. Did a little research and found out this. It all makes sense to me 
1) Using a SS prop is definitely heavier and increases the flywheel effect, rotating mass. 
2) At idle speeds the prop overruns the drive shaft and causes the clutch dogs to bounce off each other. Hence the bucket of bolts noise. 
3) Does not seem to affect two cycle engines. 
Possibly because of the actual power pulses
being each rotation. Four strokes fire every other rotation. 
Anyway that’s what I found out about the problem. Really interesting and if anyone has 
more info I would love to hear about it.


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## Rene L. Vila III (Apr 9, 2019)

I’m unsure if the smaller Suzukis have a white wire that comes off ecu and goes directly to battery. It’s to give clear power to ecu. If that terminal at battery is corroded that motor will do all sorts of crazy things.


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