2003 DF140 quit and now won't start

[JosephO]

I just bought my first boat (used) last fall and took it out yesterday for the maiden voyage. The main is a 2003 DF140 with 600 hours. I just had the shop fully service the engine - they replaced a ton of stuff that needed attention, but other than that they said things looked good. The shop has a great reputation and mechanics are extremely knowledgeable.

It was blowing hard out on the water with a ton of chop, but I managed to bounce around for about an hour before heading home. While I was out I spent about 10-15 minutes just idling while I monkeyed around with some of the electronics (radio, GPS, etc.). Everything felt great and the engine performed as expected. Right at the entrance to the Marina on my way back I came off the throttle, and after slowing down moved the tiller into neutral for a few moments, I took it back out of neutral and the engine cut off. I moved the tiller back to neutral, turned key to on, waited for beep and red light to go off, tried restarting - it turns over great, catches like it's going to fire, then nothing. Thinking I might have bumped the kill switch I removed the plastic kill switch key and reinserted, tried to start again same result. Tried a couple more times same thing. Power didn't seem to be an issue as all electronics were working and motor trim/tilt worked fine. I tried starting with it in neutral and the tiller moved forward, same result.

I searched the forum and read a few posts about the kill switch and neutral safety switch, but it sound like those will prevent the engine from even turning over, which isn't the case for my situation.

I had to get towed back in, and before I yank it out of the marina and trailer it back to the shop that serviced the engines was looking for any suggestions from the forum on trouble shooting. I'm a newbie and still suffering the humiliation of my maiden voyage FAIL so be gentle.

[Moonlighter]

One thing to check is if your fuel tank (underfloor) has an anti-syphon valve fitted to the outlet. They are incorporated into the tank outlet fitting where the hose attaches. They are a standard fitment on many US built boats.

A stuck/faulty anti-syphon (AS) valve can cause symptoms just like you had. Experienced it first hand.

At higher revs the greater fuel flow volume has enough pressure to hold the AS valve open, but as you come back to idle, the fuel flow slows and the faulty valve closes, starving the engine of fuel.

Did you try pumping the fuel primer bulb? Give it a try, as the force can suck fuel thru the anti-syphon valve and get things going at least temporarily. If this is the issue the bulb will likely be flat or very soft when you check.

If the AS valve is the problem, the solution is cheap and easy to do yourself. Take the fuel hose off the tank fitting. Use a spanner to undo the AS valve from the tank. You will see the valve components inside the fitting - simple ball, spring, seat. You can now do one of two things: simply replace the AS valve with a normal tank takeoff fitting with no valve, or, you can take the AS valve to your work bench and punch the internal ball, seat and spring out. Then reinstall the empty valve. Use some fuel resistant thread gasket goo to make sure the threads are well sealed. Allow to set. Reattach the fuel hose, using 2 x stainless steel hose clamps.

The AS valves are not a legal requirement for outboard powered boats, so removing them is really removing a problem that is going to happen at some stage in the future anyway. So even if this isnt the problem, there is no downside other than 30 minutes of your time.

If this isnt the problem, then there are other possibilities. As you noted, the neutral throttle switch on the engine usually doesnt stop the engine from starting but restricts the revs to under 3000rpm. The one on the binnacle wont let the engine start.

The other thing affecting starting and idle is the IAC valve (idle air control). They can get stuck or fail, and its important to get them checked quickly because, athough rare, a short in them can damage the ecu. And that costs $$$ to replace. Usually though they can just be replaced and reset and all good. The Suzuki marine version of this part is quite expensive, but its made by Mitsubishi and is common to quite a few cars. Those versions are far cheaper. Maybe your mechanic can help,out in that regard with sourcing a less expensive but still genuine Mitsi version.

[JosephO]

Moonlighter -
So I went down to the marina today and had them take my boat from the racks to the wash down area. Put the motor flusher on, jumped in the boat, turned key to on, red lights, beep, turned to start and it fired right up. I let it run at idle for a couple minutes then moved the throttle forward and upped the RPMs for another minute or so. I backed the throttle into the idle position and it immediately quit. I tried restarting, it turns over but won't fire - same problem I had out on the water.

With the motor off I then moved the throttle forward, returned to idle position, moved throttle to reverse position, and back to idle. I tried starting and it fired right up again. I repeated the sequence of upping the RPMs and going back to idle and it immediately died again.

Again with the motor off, this time rather than moving the throttle forward/back I moved the throttle forward, tried starting, and it fired right up. What's interesting is I tried this on the water the other day when it failed and it didn't start, but maybe I didn't have the throttle forward enough. Again, I returned to idle and it quit.

I ran through these sequences a couple more times and only once was I able to return to idle and have it stay running. Probably when I took it out for a test run the other day on the water I just got lucky the first time when I was idling and testing out all the electronics.

I'm thinking the problem is more than likely the IAC valve rather than the anti-syphon valve on the fuel tank.

Thoughts?

[Moonlighter]

Did you check the fuel primer valve? Flat or normal?

But yes, sounding more like IAC valve.

If you check the parts section on this forum and use your engine year and hp you should be able to find the IAC and a exploded diagram.

EDIT:

Just did the search for you, found this one and it could be the part you need, but check your engine serial number to see if it matches the engines this part is for.

https://www.boats.net/product/suzuki...d89fa6a7acb141


Here is the exploded view of the manifold to show where it fits.

https://www.boats.net/catalog/suzuki...ntake-manifold

[JosephO]

Fuel primer bulbs were plump and firm!

Given that the boat is an '03 and the motor is original I'm going to just get everything out of the way regarding what seems to be the usual nonsense with Suzukis. New kill switch, new neutral safety switch, and new IAC. I'm a novice so a little hesitant on the calibration procedures for the new IAC, but I'll figure it out.....seems like enough material online that I can muddle my way through it.

I'll be focused on picking up all the new parts this week and will post the results next weekend after what will hopefully amount to a successful fix for my problems. I just want to eliminate everything I can - I don't want to have to mess around with this at all during my first year on the water.

Will keep you posted, and thanks for the insight. Much appreciated!

[catacom225]

Joseph I took my IAC to an auto electrician who confirmed it was dead before i spent money for nothing, I'm thinking you should be hearing a error or fault code , also what type of fuel did you fill up with

[JosephO]

Update on my situation.

I went down to the mechanic that did the full service on the engine and explained my suspicions that the IAC might be the culprit. He said there should be an audible fault code if that was the case (like catacom225 described) and immediately said the likely culprit was the neutral safety switch on the main engine. I decided to leave the IAC untouched, and replaced the Neutral Safety Switch with part number 37721-99E11. I moved the throttle around in gear and out of gear and everything looked good visually with respect to the position of the newly installed neutral safety switch mechanism and throttle control. I did not attempt to re-start the engine at this point.

I moved on to replacing the kill switch. We weren't entirely sure on the part number since I hadn't removed the old one or taken a picture, so the shop gave me part number 37830-95D03. After I replaced the kill switch I then moved on to starting up the engine. When I turn the ignition to on I see a check engine light illuminated continuously (no blinking), there are no beeps, and when I try to start I get absolutely nothing, not even a click. I'm thinking the kill switch might be the wrong one - from what I can see part 37820-92E04 probably is what I needed. Would the wrong kill switch cause the check engine light to illuminate when ignition is moved to on and lead to the engine not even turning over?

[catacom225]

It Sounds like there just out of adjustment, Visually inspect the switch and confirm it is closed. A simple way to check would be to turn the key to start and wiggle the control lever back and forth. not sure why you would replace switches without checking continuity. don't have my service manual with me , but i'm sure moonlighter will explain how to check the circuits with a test lamp