2005 DF 50 hard to start, rough idle, stalls

[tjl76evinrude]

ive had this 2005 suzuki df-50 for a few years now and from the time i got it, it has never seemed to idle smoothly and when starting it it will crank for maybe 5+ seconds before it hits, then it might fire up and stall, i crank it again and stays running. also when you rev it off idle it has a miss than can stall the motor occasionally. im about out of ideas and dont want to keep throwing parts at it. it runs great all the way up to full throttle.

few facts about it, the previous owner always ran crap ethanol pump gas in it. he had it since new and when i bought it, it only had about 94 hours on it. sadly ive only put about 10 hours on it over the last few years.

high pressure fuel pump seized up. i replaced it along with cleaning the scale and ethanol corrosion in the vapor separation tank. it has new ngk spark plugs.
from the time i got it it has only had non-ethanol 90 in it. it has a water separator on it.

i have good flow coming out of the high pressure fuel filter. i pulled the fuel injectors, they look perfectly clean.

when i got to start it, it cranks up to 5 seconds then will fire up and stall, then fires up and will stay running. while idling it is pretty unsmooth, you can see the motor shaking and you can hear it missing occasionally. if you rev it off an idle it will hesitate/miss then pick up or stall. once above an idle its perfect,

there is no error codes that i have found.

anyone got any tips or things to check?

 

[tjl76evinrude]

Little update.
Did some more experimenting today. To rule out voltage, i bypassed my battery switch and put another good battery with the starter battery in parallel. No change.
While idling rough like usual, i disconnected the coils one at a time and it quickly died. Restart and try again. It died the same with each coil. Did the same test with the injectors, pull the plug one at a time. Same thing, died quick. Seems odd to me it would not run on 2 cylinders. The equipment i work on mainly uses v twin motors 18-20 horsepower, they run very good on 1 cyl. Either way, this told me it wasnt 1 coil or 1 injector. I was getting flow out of the high pressure fuel pump through the fuel filter so i didnt change it previously. I had bought a new high pressure filter just in case. So today i figured WTF and went to change the high pressure filter. Pulled it out, the clean fuel poured out into a bottle then i lightly tapped it and a bunch of what looked like tobacco chewers spit came out. Tapped a few more times and more funky dip spit and blackish fuel come out. I try to blow through it and can barely get any flow through. This couldnt have been helping me out. new filter in and it seems to be slightly happier but still rough and hesitates. So im pretty sure it was so funky that some of the finer funkiness made it to the injectors, all of them. Its been doing this since i got it so this whole time its been pushing garbage against this filter and right into the injectors. So i think i will be pulling them and sending them out for a thourough test and cleaning.

So once again it seems like good old ethanol damage again.

 

[tjl76evinrude]

Anything? anybody?

since posting earlier i have had the injectors tested and cleaned, that didnt fix it. i then found my fuel pressure to be a little high so i replaced the 200$ fuel pressure regulator. no change.

i have replaced the fuel separator, the high pressure AND low pressure fuel pumps, the fuel regulator, had the injectors cleaned and basically rebuilt and cleaned the entire fuel system. pretty sure it has nothing to do with fuel. i have never received any codes from any sensors until tonight when i forgot to hook the IAC valve up. i'll be working back at it tomorrow testing sensors.

 

[tjl76evinrude]

I plugged in my laptop with suzuki diagnostics. Nothing crazy going on. Need to do more testing. Suspecting a sensor that isnt showing up as bad and throwing an error but maybe just not reading right.

 

[99yam40]

pretty sure it has nothing to do with fuel.

Make sure, do not just think.

Tank and lines are probably full of what you found in filter

Test eveything you can to make sure they are in spec, then work on things you cannot test.

Did the flow rates and spray pattern have a problem when they tested injectors before they cleaned them?

 

[tjl76evinrude]

i have been through the whole fuel system so im sure its clear. that scuzzy filter and the regulator were the last of it. i got the motor back on my laptop and did all the testing i could think of. i then ohmed out the sensors and everything checks out. now im wondering if it isnt a problem with temperature. the motor has been running rich. i have already pulled my thermostat and it checked out, opened wide about 130-140. im going to try to do the water pressure relief valve next along with with salt away flush. im going to start a different thread with some pictures of the fuel gunk buildup in my intake. i also have the famous corroded plug in the engine holder. it looks good from the outside but its froze solid in place. also i checked my anodes, i think they were original. pretty ate up.