# Suzuki df20 runs rough 5 minutes (after red light turns on), dies



## JPan

Was able to "get by" all day, just couldn't go anywhere fast and had to start again every 5 minutes. Don't think its overheating, as the telltale is shooting plenty of water. Tried two different tanks, both with fresh gas and well vented. Seems to only happen in forward gear:
1. Starts fine (electric start)
2. Put in forward gear
3. Runs fine for a few seconds (even seems to accelerate normally if I open up the throttle)
4. Red light suddenly turns on at the same time that it starts running super rough
5. Runs rough for about 5 minutes, not letting me go very fast, but still pushing the boat a bit
6. Turns off
7. Rinse and repeat...

Oh, and although it's been sitting for a few months, it was checked out by a Suzuki mechanic and changed the oil before it sat. Gas had stabilizer. Any ideas would be greatly appreciated. It's a 2015 model


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## Finsleft258

How long did it sit? Have you checked the oil level? The red light will come on for oil pressure.


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## Fishtex

JPan said:


> Was able to "get by" all day, just couldn't go anywhere fast and had to start again every 5 minutes. Don't think its overheating, as the telltale is shooting plenty of water. Tried two different tanks, both with fresh gas and well vented. Seems to only happen in forward gear:
> 1. Starts fine (electric start)
> 2. Put in forward gear
> 3. Runs fine for a few seconds (even seems to accelerate normally if I open up the throttle)
> 4. Red light suddenly turns on at the same time that it starts running super rough
> 5. Runs rough for about 5 minutes, not letting me go very fast, but still pushing the boat a bit
> 6. Turns off
> 7. Rinse and repeat...
> 
> Oh, and although it's been sitting for a few months, it was checked out by a Suzuki mechanic and changed the oil before it sat. Gas had stabilizer. Any ideas would be greatly appreciated. It's a 2015 model


I have same motor and a similar experience and it turned out to be the fuel line bulb. I put a much higher quality line and bulb on It fired right up and ran normal. 
My theory is the bulb was losing pressure and thus causing issues with the EFI, etc. the OEM line and bulb is not of great quality and had deteriorated over the last 3 years, but not enough to visually be obvious. It felt like it was holding pressure but it was losing it after you pumped it up a bit. 
I had my boat at the shop and my tech was just getting ready to start diagnostics when I brought up the fuel bulb. He said let’s put a good line/bulb on it and you go run it before we start throwing money at it. Don’t buy some cheap line/bulb from Amazon or Academy. 

Not sure this is your issue but I would check that line/bulb before going any deeper. Good Luck.


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## Chris Beutel

Check you pick up tube in the tank as well. Mine came loose and once the fuel got below a certian level the engine could not pull it anymore and it would stall out.


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## ActionCraft

Check your plugs my DF 20A did the same thing.


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## Petelynch

JPan said:


> Was able to "get by" all day, just couldn't go anywhere fast and had to start again every 5 minutes. Don't think its overheating, as the telltale is shooting plenty of water. Tried two different tanks, both with fresh gas and well vented. Seems to only happen in forward gear:
> 1. Starts fine (electric start)
> 2. Put in forward gear
> 3. Runs fine for a few seconds (even seems to accelerate normally if I open up the throttle)
> 4. Red light suddenly turns on at the same time that it starts running super rough
> 5. Runs rough for about 5 minutes, not letting me go very fast, but still pushing the boat a bit
> 6. Turns off
> 7. Rinse and repeat...
> 
> Oh, and although it's been sitting for a few months, it was checked out by a Suzuki mechanic and changed the oil before it sat. Gas had stabilizer. Any ideas would be greatly appreciated. It's a 2015 model


Your engine is overheating.
Only reason red light comes on us overheat or low oil period.


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## JPan

Indeed, it was overheating. I purchased the SDS cables and diagnostic software it it showed temperature gradient alarms corresponding to the red lights. The telltale is absolutely not the complete story. It may be spitting out a lot of water, but the cylinder block may not be getting enough (or any) water at the same time. I'm closer to solving this, but not yet. Replacing thermostat and planning to do a serious "flush" to clear out the cooling channels, as I noticed a lot of gunk, mostly salt, in the cylinder block when I removed the thermostat.


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## JC Designs

Probably time to change the internal anodes as well!


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## con kso

Interested in how this has turned out for you. 

I have a 2019 DF20A and after almost a year of ownership and 20hours on it, it now will throw a red light code (I believe it was 4 blinking red followed by 2 blinking red, aka 4-2) after I run it at about 3/4 throttle (18 mph approx) and then throttle down - the engine will go into "Limp" mode until I let it sit for awhile. RPMs are retarded down to around 2-3k. 

Tell tale is spitting fine, new impeller, and checked my internal anode passage to see if water was pumping through up there (indicating functioning thermostat) all looked good - and less corroded then inside of your engine! 

Please report back how this all worked out for you. 

My outboard is in the shop now - who knows when I'll get it back. Sucks.


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## JPan

Many of the symptoms sound the same, but I wasn't getting a blinking red light. I would suggest investing in the diagnostic cable and software (SDS) which gives you a ton of information. I think I paid around $65. The only caveat is that with these smaller engines, SDS only works when the engine is running or via a special cable that powers the ECM (should the engine not be in running condition). Gives a ton of information. It's how I found out I had been getting a temperature gradient alarm.


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## con kso

Thanks for the quick response - *do you have a link to the correct cable?* I'd definitely pick one up for $65. My motor runs fine at idle - so I'd definitely be able to power it up for the data. 

Super weird - for almost a whole year the thing runs flawlessly and then within the last three weeks it starts acting up - but only after being run for 20 - 30 minutes and then usually when throttling down from high rpms. 

Please keep me posted on the progress of your trouble shooting and I will post what I learn from my outboard here too.


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## JPan

I just looked on Amazon and they're currently out of stock. Maybe you can find it somewhere else, but it's 
moto-solution Diagnostic USB Cable Kit for Suzuki SDS 8.30 

I also posted my problem on the suzukioutboarforum.com and got a lot of useful information there. I suggest you check it out


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## con kso

Thanks! Yes I think I saw your thread - you bought the cable and it didn't say it was a cross over for df20a but it ended up working - ok I'll go check it out. 

Your motor still not functioning correctly now though, right?


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## JPan

Not yet. I've flushed it with Salt Away and also with vinegar, replaced the thermostat and the anode, and I'll be replacing the impeller soon. One of the members responding to my other thread is convinced that I need to clear out some probably clogged channels in the engine block, but I'm scared to do that (outside my comfort zone). I'll see if the problem is still there after I replace the impeller. If so, I'll probably throw in the towel and get a mechanic.


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## con kso

Yeah - I saw that comment on the other site. 

I still have time on my warranty so I wouldn't attempt that - but I do have a friend who's an outboard mechanic and he came by the other day to run it, show me where the internal anode and thermostat is located. We ran the motor and flushed it both through the upper port and using muffs - he told me about a 15hp Suzuki (think it was a '15) that he helped get running and he told me about accessing those cooling passages. He said it's not that difficult and he said he was amazed at how clogged the passages were for this particular motor - it was used on a sailboat tender so it basically never got flushed but he said that there were constrictions in the passages caused by overlap of gaskets. He thought it was a bad design. They did manage to get the passages cleared and the motor ran fine. 

I also have a friend who has our same exact motor DF20a who uses it on his aluminum fishing boat. He probably fires it up five times a week fishing where he lives in Baja. He's got close to 3500 hours on his with only one problem when a small wire frayed to one of the fuel injectors - other than that the motor's been perfect. In fact, it was because of his experience that I bought my Suzuki. 

I've got mine at a Suzuki dealer right now - I'll let you know how it goes.


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## con kso

Just got a call from dealer/shop - they ran the diagnostics on my motor and it was showing a Cam Position Sensor problem - mechanic said, "we've been authorized to remove, replace and retest" the sensor so we will see (fingers crossed warranty work and claim and most of all payment goes smooth). I asked if there were any other codes thrown and he said only cam position sensor. No overheat. The part is supposed to come next week and then they'll let me know - I will report back.


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## Seymour fish

JPan said:


> Indeed, it was overheating. I purchased the SDS cables and diagnostic software it it showed temperature gradient alarms corresponding to the red lights. The telltale is absolutely not the complete story. It may be spitting out a lot of water, but the cylinder block may not be getting enough (or any) water at the same time. I'm closer to solving this, but not yet. Replacing thermostat and planning to do a serious "flush" to clear out the cooling channels, as I noticed a lot of gunk, mostly salt, in the cylinder block when I removed the thermostat.
> View attachment 133200


Might have to acid flush the water jackets in the head


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## con kso

con kso said:


> Just got a call from dealer/shop - they ran the diagnostics on my motor and it was showing a Cam Position Sensor problem - mechanic said, "we've been authorized to remove, replace and retest" the sensor so we will see (fingers crossed warranty work and claim and most of all payment goes smooth). I asked if there were any other codes thrown and he said only cam position sensor. No overheat. The part is supposed to come next week and then they'll let me know - I will report back.


Ok - so I promised to report back: Got a call from the shop and was told that my motor was ready for pickup. Jammed over and the friendly shop owner said, "it's all ready, we've run it and it's not throwing any more codes... have a nice day!". Everything covered under warranty. I took the motor home, reinstalled it onto my skiff and took it out yesterday on a long run. The thing ran perfectly. I'm going to look into picking up a diagnostic cable - I can see how useful it will be in the future.


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## The optimist

con kso said:


> Just got a call from dealer/shop - they ran the diagnostics on my motor and it was showing a Cam Position Sensor problem - mechanic said, "we've been authorized to remove, replace and retest" the sensor so we will see (fingers crossed warranty work and claim and most of all payment goes smooth). I asked if there were any other codes thrown and he said only cam position sensor. No overheat. The part is supposed to come next week and then they'll let me know - I will report back.


Was the problem cps that made the engine get hot?


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## Kal

I have a 2014 and had the same problem a few days ago. It was similar to the time I got gas with water in it, but the red light was on. The steady red light is for overheating, RPM, or oil pressure. 95% of the time I use the motor in salt water. I always flush with a hose for 5 minutes and it in a tank for 10. I removed the thermostat, and it tested good. There was plenty of water coming through the bypass at the thermostat, but no water coming from behind it. I pulled the head and found the water jacket around the cylinders completely clogged, but the water jacket around the head was fairly clean. I asked Suzuki about what could cause this, and how to prevent it. There answer was to take it to a dealership, which I don't have the time or money to do. I got it all back together with a new head gasket and it runs good. I guess I will have to pull the thermostat and flush with the hose occasionally. It has been a great motor other than this issue. If the timing gets off line the hole in the lock washer under the flywheel with the mark and the punch mark with the 1 or 2 on the cam pulley with the mark. Hope this helps.


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