df 60 wont run longer than 30 seconds

[PaulinFL]

I have a df 60 1999 4 stroke on a 24ft pontoon. the motor has been running great. I recently change impeller,oil and checked compression. Compression was good. I took the boat out monday and it ran fine but when loading it did stall but cranked back up. I flushed the motor with muffs, while doing this the motor was running rough and stalled like it was not getting enough gas. If I idled it up it would run fine. The motor sat for 36 hours and I started it up again and had smoke coming out of exhaust( did not run it more than 30 seconds because of the smoke). I checked oil and smelled gas in my oil. I drained the oil and it had an odor of gas but not a lot and the oil level was not high on the dipstick. The oil looked thin but not milky. I removed the low pressure fuel pump and pumped the bulb but no leaks. I even pumped the rod going in to the LP fuel pump and no leaks. I refilled oil and cranked. now it wont stay cranked more than 10-15 seconds. After it does run a little the smoke will go away but it does smell like oil. I checked plugs and the bottom plug is wet. I installed 4 new plugs and same issue. i also checked my bulb and fuel water separator and all is well there. I have read about the float and pin inside the VST but never any issues with smoke and from what I have read when it is this issue the motor runs fine it just makes oil. Oh and I did take a screwdriver to each injector and I here a ticking noise on each. Im not sure if that means anything but I read it somewhere and tried it.
any suggestions would be helpful.

[aquamort]

Maybe try another compression check? Especially number 4. I think the DF90 is set up like the 140 if so there could be a problem in the VST - regulator or needle and seat? this fills the VST up with fuel and floods the engine. Check the vacuum hose coming off the VST that goes to the tappet cover to see if its wet after running.
Good luck

[PaulinFL]

Thanks Ill try that. If the VSt is getting flooded that would mean there is no or low levelsof fuel getting the the injector tube. Is there anyway to test that before tearing it all apart. Or maybe it would be best to tear into it and check it all out. I feel like its fuel related since the problem has went from running ok to cranking fine and then stalling after 30 seconds. im new to 4 strokes and never worked on one before. But I really like the motor when its running good.

[aquamort]

Thanks Ill try that. If the VSt is getting flooded that would mean there is no or low levelsof fuel getting the the injector tube. Is there anyway to test that before tearing it all apart. Or maybe it would be best to tear into it and check it all out. I feel like its fuel related since the problem has went from running ok to cranking fine and then stalling after 30 seconds. im new to 4 strokes and never worked on one before. But I really like the motor when its running good.

If the VST is flooding its not going to change how much fuel is going into the injector rail, it would be the same amount as if the level was correct. I think no4 spark plug being wet is the a good clue. Id be doing a quick compression check as i said. Id do that before pulling manifolds etc off. Also after cranking etc for a bit check that vacuum hose to see if its wet.

[PaulinFL]

OK i done a compression check and (1-4) 112,110,115 & 125

Im not exactly sure about the hose coming from the VST. here is what ive found.
Hose on top left comes from LP fuel pump
top right rear goes to filter then to rail gas trickles
top right front goes to plastic tank at front of motor. wet but no gas. is this the vaccum line?
right side mid way up from bottom goes to apiece on bottom of rail. gas pours out.
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Bottom left goes to junction then front side of oil case. Water in line. just enough to know its water
bottom right goes to junction then to front of motor water in line just enough to know its water.

I did not run it before taking the hoses off.

[aquamort]

Not sure if this photo is going to work but the hose im talking about is an evaporative hose that comes out of the VST and goes into the top right of tappet cover when looking from behind. Definately shouldnt have fuel pouring out of it.

[PaulinFL]

[IMG]View My Video[/IMG]
its running better for some reason in this video than what it has been. i think I need to invest in a service manual.
I'll see if I can identify what hose goes to the tappet cover

Ive also noticed since ive changed the oil I no longer smell gas in the oil. Maybe because I have not run it that much. And the smoke is only a very little when I first crank it for the first time.

[aquamort]

Sounds like those valves could do with some adjusting? Have you checked the IAC valve? Its in the intake manifold. A spray with some carby cleaner or use some solvent and a toothbrush maybe to clean it up.

How does it run with the revs lifted with the fast idle lever?

I would of thought the 60's would have an evaporative hose out the top of the VST as well? Its just vacuum hose size. When my float was stuffed fuel would actually squirt out of this hose when running!

[PaulinFL]

well i think i have it figured out...maybe. i went to the local suzuki dealer and bought a service manual and while I was there the guy really felt strongly that it was still the LP fuel pump so I bought a diaphragm kit and replaced it. Even though I checked it first I found that there was some gas on the back side of the piston when I took it out this time. I didnt see a crack in the diaphragm but I think it was leaking some where. Started it up and basically the same thing just ran longer. While checking things out I found a loose wire on the front of the air intake throttle body. IN checking this out I started having problems with it cranking. Sillinoid clicking. Anyway come to find out the voltage was low going to the motor. terminal on the battery was corroded. after cleaning its running alot better. Maybe a combination of low voltage and the LP pump leaking a bit was the problem. Im taking it to the water in the morning and we'll see. the wire on the front I think is the air temp sensor. I still need to check out your advise about adjusting the valves. I didn't even notice it until you said something. Im not sure thats something i need to dive in to just yet. I appreciate you taking the time to help me so far.

[PaulinFL]

What is the IAC valve? how would it be listed in the manual?

It runs good with the revs up now, before it would just die.

There is a evaporative hose that goes from the VSt to the top of the plastic air intake. I checked it before during and after running and never had a sign of fuel. I even took it off at the VST and nothing.

[aquamort]

Good one. Ive actually heard before that the zukes dont run well with poor voltage so hopefully your on to something there!

IAC valve (think its Idle Air Control) its just a solenoid near the throttle body. It controls your idle. Not that hard to clean out.

The valves sound loose so wont really cause any running problems as opposed to if they were tight.

[PaulinFL]

well that was not the fix. When I first crank it it runs for 10-15 seconds and shuts off then cranks back up. After a few cycles of this its like it warms up and then idles fine. Out on the water the throttle just bogs downs(could this be caused the IAC valve). The first 25% of throttle does better than the rest. I was not on the water long maybe 5 minutes but it got progressively worse and when I went to load and gave it throttle it would shut off. Almost like its flooding. Could it be an injector or could it still be the vst flooding out. IM going to look at the fuel filter between the HP pump and the fuel rail also.

[PaulinFL]

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Is the IAC valve the connection on the bottom of the throttle body where the wire is

[aquamort]

Trying to work out your photo? But i think what your pointing to is closed throttle switch?

IAC will only affect the running at idle anyway mate so lets get back to basics. It only started running bad after you changed the water pump impeller? I cant really think of anything you could disturb while doing this job to cause this problem?

Do you have a fuel pressure gauge? We know your compression is good. Need to check fuel and spark though from what your saying it does sound like some sort of fuel/fuel control problem?

Also check the MAP sensor isnt blocked. They can block up with carbon. Are there any codes being thrown out at all? A general check of all connections to sensors etc would be a good idea too.

[PaulinFL]

I changed the impeller out a couple of months ago. I have taken it out several times since then with no issues.

I found the IAC and its on the intake manifold.
The photo turned sideways for some reason?? sorry

I dont have a fuel pressure gauge but I can look at getting one. where would be the best place to check it? Top of fuel rail?

No codes that I know of.

Ill check spark and the MAP sensor. You would think a service manual would show you where these sensors are located. I guess since you talked about carbon build up it may be around the exhaust manifold. I found a diagram of the sensor so maybe I can find it.