2003 Suzuki DF15 Hard Starting When Cold

[michaelnel]

Hi

I just bought a clean used Klamath 14 footer with a 2003 Suzuki DF15 4 stroke outboard. It is *very* hard to start when the engine is cold (cold around here being 90F air temp lately). The starting procedure I have used (I have no manual) for this pull-start engine is:

1) Pump bulb until firm
2) Full choke
3) Make sure dead man clip is in place
4) Closed throttle
5) Pull, pull, pull, pull, etc.

Sometimes it will start after 10 or more pulls, but this morning in 60F temps I pulled it about 30 times without so much as a cough. Tried full choke, 1/2 choke, no choke, no throttle, a little throttle... nothing.

The little red light does flash when pulling the cord, I assume that means ignition is working?

I tried replacing the two spark plugs, but the stock ones looked good, tan insulators and sharp electrode edges, slightly larger than spec gap. I pulled the cowl off and it does look like the manual choke valve is opening and closing properly. This 2003 has the Mikuni carb with manual choke, no enrichener that I can find.

When we succeed in getting the engine started cold, it idles smoothly, and runs great. Transition off idle is smooth, and it is smooth all the way up to cruise, and presents no more problems until the next cold start. Starts on first pull when it is warmed up.

I put some SeaFoam in the tank hoping for improvement, did not get any.

I will try some fresh gas. I don't know how long that gas has been in the tank, but I was under the impression from the owner less than a month.

Any other ideas?

 

[michaelnel]

As an experiment, I sprayed some of that ether starting spray into the intake. Started right up cold, but the idle was really really low. I let it warm up (running it on the flusher attachment) until the water coming out of the tell-tale was warm, shut it off and it restarted easily, but the idle was still real low. Hooked up a tach and it was idling around 600 RPMs. I increased it to about 900 RPMs. It is still warmed up, so it still starts easily. Will have to wait until it is cold again to retest.

OH, and I checked the choke valve. With the engine idling smoothly at 900 RPMs, pulled the choke knob all the way out and RPMs dropped quite a bit and it was kind of stumbling, so based on a primitive test I would say the choke valve *is* richening the mixture. Not sure if it is doing it enough, but it is doing it some.

 

[michaelnel]

Found spec for idle speed, it is supposed to be 960-1050 RPMs in gear. So I set it to about 1000 in gear. We'll see what the next cold start brings.

 

[michaelnel]

Let it sit for about an hour, and it will not start, choke or not.

 

[michaelnel]

Pulled the pilot jet. It appears to be completely clogged. I cannot see light through it, and compressed air did not clear it. I don't have any carb cleaner, but I did try some map sensor cleaner and that did not clear it. Now I have it in my ultrasonic cleaner running heated with a mild acidic solution to see if that will clear it. I know the hole will be tiny, but there should be a hole that you can see light through, and I cannot.

 

[michaelnel]

So... that jet is unlike any I have encountered before. The screw top is exposed to the air. It has three holes in the side and a tiny one in the bottom so I assume fuel enters the jet through the three holes and exits through the tiny one. After cleaning it a couple times with ultrasound and carb cleaner and a tiny copper wire I am confident those passages are clean. Reinstalled it, same thing. Starts with starter fluid when cold (which is about 90F air temp right now) but will not start cold without the starter fluid.

 

[99yam40]

My guess is is that it needs a slight throttle setting to give some air and then the choke needs to close to force fuel rich.

make sure choke plates are closing completly.
I do not think the pilots jet would be where fuel is drawn from during cold start, but I could be wrong.

it would be wise to clean the whole carb and set to spec

 

[michaelnel]

My guess is is that it needs a slight throttle setting to give some air and then the choke needs to close to force fuel rich.

This has remote steering and shift / throttle. I cannot affect the RPMs without it kicking into gear, unless I pull the engine cowl off and manually adjust the idle speed. I will try that as an experiment though. It's not practical on the water.

make sure choke plates are closing completly.

It seems to be. I will disconnect the linkage to see what the limits of movement are and make sure I am getting that much travel.

I do not think the pilots jet would be where fuel is drawn from during cold start, but I could be wrong.

I agree. Pilot circuit handles the transition from idle to the needle. I just checked and cleaned the pilot jet because it is sitting right out there easy to access. I doubted cleaning it would help, but it would not hurt either.

it would be wise to clean the whole carb and set to spec

Previous owner (who appears to be a good mechanic) said he already did clean it and it made no difference. I did find this morning that the fuel filter looks to be the original one and was very dark and dirty looking. I got a replacement filter at an auto supply. Installed it but have not had a chance to try starting cold with it in there. I also ordered a fuel pump rebuild kit, it probably needs it although disconnecting the output line and pulling the starter does show fuel being pumped.

 

[99yam40]

all remotes I have seen have a way to advance the throttle without putting in gear.
do some searching and you will find it.

Yamaha has one that you push a button on the controls to disconnect the shift so throttle can be advanced by itself.
I have not dealt with Suzuki s much so not much help

 

[michaelnel]

The Suzuki NA12S control does have a fast idle lever, but it does not seem to work. Perhaps I don't know how to work it. When it is in the raised position the shifter is locked, but running the lever from one extreme to the other has no effect on the throttle. When the lever is down, if you depress the red button on the shifter/throttle handle you can advance that lever, but it has no effect on the throttle until after it clunks into either forward or reverse.

I have searched for hours for info on the NA12S. I cannot find a manual for it, and the previous owner just said the fast idle was not hooked up. I found exploded parts diagrams but I can't figure out how it is supposed to work from those, so I guess I will just have to dismount it and start taking it apart.

Support for Suzuki stuff on the internet is not very good. I won't buy another boat with a Suzuki motor. You can get help easily for Evinrude, Johnson, and Mercury... not so much Suzuki.

 

[99yam40]

fast idle lever should work,
need to take apart and see what is wrong

 

[michaelnel]

Yep, that is my next step, thanks.

 

[michaelnel]

I replaced the fuel lines inside the cowl with some good Gates line and new clamps and a new filter. I think the ethanol had done a job on those old lines. I feel better about having new stuff in there anyway. The fuel filter looked like it had been in there since it was new... dark, with a lot of black stuff in it (probably debris from the ethanol eating the fuel lines. The new one is crystal clear and I can see the gas in it well.

I took the NA 12S remote control off and removed the side panel. It seems well greased, although I found a small wasp nest in there! Old one, with no wasps, but the papery chambered structure was in there. Very strange. I cleaned that out, and I don't think that had anything to do with anything. Studied the mechanism and thought I figured out how it works, but did not see anything wrong. I put it back together, and lo and behold, it works now. Not quite right... it lays flat at 9:00 position and travels up to about 11:00 position at its stop. It only works the throttle from about 10:00 to 11:00, but at least it works. There may be some adjustment in there for that, I did see some adjusters with locknuts but did not mess with them.

And now it starts with the choke when cold! Thanks guys for the help!