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Hot Start Problem occasional short miss idle

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eyefish

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"Motor is: '05 DF-90. 140

"Motor is: '05 DF-90. 140 hrs. Pampered engine. Lives on trailer in climate controlled garage when not in use. Cold start is perfect. Hot start...can be tricky. You can crank forever, & won't start. If you stop cranking, & start cranking again, it will start. (ocasionally you have to try a couple of times)
When this happens....you can smell hydrocarbons immediately after it starts.
This doesn't happen all the time, but at least 50% of the time on Hot Starts.
Also.....lately has an occasional misfire at idle (hot or cold; in neutral, but especially in reverse at idle) Misfire only lasts for one or 2 revolutions of engine.....very brief.
I just replaced the sp plugs & fuel filter a few days ago, but not had a chance to retry.
Spark plugs & fuel filter that came out looked perfect....I don't expect the problem is resolved.
No check engine lite.
(I DO have the Suzuki Software & Hardware to hook it up to a laptop, but haven't done so yet....I am an ASE Certified Volvo AUTOMOTIVE Dealership Master Technician since '74 (semi-retired now) but have no working experience with Suzuki OBs....big difference in the cramped world of OBs compared to under the hood of a car)
Any experienced help/advice would be greatly appreciated.
I was advised that the problem may lie in a maladjusted Throttle Switch @ idle, but I seem to believe that isn't the problem...although....I haven't checked yet.
Thanks."
 
"Just-In-Time,

I want to ad


"Just-In-Time,

I want to add.....I had to remove the anti-siphon valve from the gas tank the 1st day I splashed the new boat & motor in '05.
It wouldn't stay running (under load) without continously pumping the primer bulb.
So the boat is without an anti-siphon valve since.
I wanted to add that in case you may think it could have some bearing on the hot-start prtoblem.
Thanks,"
 
"JUST-IN-TIME,

Today was th


"JUST-IN-TIME,

Today was the 1st time I got to run the boat since I installed the spark plugs & fuel filter a few days ago. (I have NOT tried running the Suzuki diagnostic hardware/software yet on the laptop)
Spark plugs & fuel filter that came out looked perfect....I didn't expect the problem to be resolved.
To my total amazement....the stumble (occasional miss in one of the cylinders for about 1,2 or 3 revolutions) is completely gone.
I tried it all day today.
It never happened once.
It seems to be solved.
(As I said....I am an ASE Certified Volvo AUTOMOTIVE Dealership Master Technician since '74 (semi-retired now) and I certainly didn't expect the plugs or fuel filter to resolve that stumble issue, but it is either a huge coincidence, or it fixed it)
The hot-start problem is still there, which was there from day one.
I find that the best way to keep the hot start issue to a minimum is the way I go about starting it.
If I turn the key to 'accessory' position 1st, & allow the 4 idiot lites in the Suzuki multi guage to run their course....& then I continue turning the key to "start"....it usually starts right up.
If I leave out that part of 1st turning the key to allow the idiots lites to run their course, & instead; turn the key straight to 'start'......that's when the hot-start problem is the worst.
It seems that the fuel pump needs to run for a second before the engine starts.
Does the fuel pump in this engine have a 'check-valve'? (a one-way valve that holds pressure (rest presure) in the lines?)

Also...remember that I told you that I had to 'remove' the anti-siphon valve in the gas tank on the 1st day I took this boat/motor on a shake-down cruise 3 yrs ago, because the engine could not draw fuel from the tank with it in.
That anti-siphon valve is STILL not in there....it's a straight feed fitting now on the gas tank...no anti-siphon valve.
Could that have something to do with it?

Thoughts?"
 
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