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Help! Mystery starting problem

andyak

Jet Boat Addict
Messages
94
Reaction score
43
Points
97
Boat Make
Yamaha
Year
2005
Boat Model
AR
Boat Length
23
First off I have removed and replaced exhaust gaskets on both engines. The first engine I replaced gaskets on I reinstalled and got everything hooked up started up fine.

Now 2nd engine I got everything hooked up correct - double checked connections and I get no startup joy!

I have pulled plugs that seem dry and verified spark.

I have loosened fuel line and got fuel spray. I went so far as to install backup replacement fuel pump- still seems to have pressure but I do not think fuel is being injected as I get no ignition.

Will Crank forever but no start. Can't smell gas. Other engine starts right up.

Any ideas? I am stumped.
Worked perfect before removal and new collector gasket.

Thanks in advance!!

Andy
 
make sure the safety switch under the clean out hatch is working,
 
Check all of the small stuff first. Cleanout hatch kill switch, lanyard kill switch (jiggle it, someone had it where only one engine could start because of it), throttle in neutral (juggle handle).
 
If after you perform the good above suggestions and still no start I would electrically disconnect the lanyard switch and try to start. On my 2007 the electrical connection is behind the speaker at the drivers foot.
 
Thanks guys. Covered all those. As stated everything worked perfect last Sunday when I pulled engine out.

Of course all electrical connections were reconnected. I know cleanout hath switch is good as I can crank. I know lanyard switch is good cause I saw spark on spark test. Still seems like lack of fuel injection. If I was getting fuel I would have see. Wet plugs I think. Argh.
 
Try spraying some starting fluid into the intake and see if it runs for a second. That could tell you if it is fuel delivery or not.
 
Latest update ran YDS.

Was able to turn on fuel pump heard each injector function and tested each spark plug for spark then I ran the bypass motor it made some noise and seem to run. All other motor settings were normal and I check the function of the switches and they showed up in the software as working correctly

For some reason bypass motor seem to get very warm later after engine switch was off for 20 minutes bypass motor was almost too hot to touch.

After much creaking and testing and cleaning all the spark plugs I broke it down to the throttle bodies and put my finger down each one after cranking and they were all bone dry. There seems to be plenty of fuel pressure coming from the line. At this point I wouldn't rule out some bugs crawling into the line over the last week and plugging up the fuel on the way to the injectors!

I will run YDS again tomorrow after trying to start and there's fuel pressure and run the injector test while holding open the throttle bodies and checking to see if anything sprays
 
Please keep us updated.
 
i HATE this problem. i'm always happier when the starter won't even click rather than a spinning motor that won't fire up. i used to own a sportbike shop (these are R1 sportbike motors), and a cranking motor that didn't fire up was my most dreaded problem to diagnose. luckily, i didn't see it often.

@nestofpirates has a good idea at spraying some starter fluid in there. i know you already have it narrowed to the injectors, but this will add certainty.

injector issues: unfortunately, from what i've read on the forums, this usually ends up as a bad ECM. this seems specific to the 2005 models, though i think it commonly results in the injectors over pumping. but if the YDS says you're good, i'd thoroughly reinspect the wiring on the injector portion of the harness. it's gotta be something "dumb" that YDS isn't capable of checking (like maybe continuity of the harness?): maybe you pinched a wire just enough that it separated inside the wire jacket or one of the tiny/fragile tabs inside a connector isn't seated correctly or broken at the wire? and check for bugs! ha.

if you go through and you're still at a total loss, you can swap ECMs. a pain, but in that regard, it's really nice to have a second one as a test unit.
 
Thanks for the help. I will clean injectors today and see what happens.
For future reference- does anyone know if the fx140 ECU will work in these boats?
 
@andyak Here is another option to try. My starboard engine wouldn't start at the beginning of last season. It would turn over, but not start. I did most of the checks you've done and couldn't figure it out. Did a compression test and I had ZERO compression in cylinder #3. Ended up being a stuck valve. But a compression check is the quickest and easiest way to figure that out.
 
Thanks for the info. I don't see how I could've stuck valve from pulling in action and then putting it back a week later without it running in the midst.

I ran YDS again this morning it will not let you open the butterflies when you test the injectors so I could not really tell not sure how much gas I would smell from an injectionI sprayed out the cups in the back of each of the injectors put the injectors back reassembled and proceeded to have the same result. My batteries a little low so I am charging it. My other engine would still start up right away on the battery but maybe this one needs Full juice to get going again. Crossing my fingers after battery recharge that I will have more love wish me luck.

I find it odd that AutoZone does not carry crimp on fuel injection hose clamps. Had to get fuel injection clamps that have a bolt built-in I'm sure it's not Coast Guard approved
 
Still no joy my plugs were wet this time.
I clean the plugs ran the cylinders without plugs try to dry

Clean plugs reassembled I get about the same thing a little bit of a gurgling to try to start and nothing.

My last call is to get some brand-new plugs as I think these plugs can be temperamental if they've been flooded
 
Cylinders were within 10% of the hundred psi. I don't trust this crappy Harbor freight gauge the O-ring is half worn off so I think pressures are higher.
 
So Spark = Check, Fuel = Check, Compression = Check...timing is about all that's left.
 
Stupid question ? Did you try any starting fluid ?
 
Stupid question ? Did you try any starting fluid ?

I agree...a little squirt would tell you if it was a fuel issue. But you said wet plugs so you should be getting fuel. You could also squirt a little fuel into the intake as someone cranks it...careful though.
 
Might double check the plug gap too...
 
I got new plugs. I will gap them and install them tomorrow

Meanwhile I'm taking the old plugs out and leaving the cylinders open to dry out I cranked with some seafoam and then a little Lucas oil to make sure I didn't have any deposits on the valves

Is it even possible for the ECM to be bad if I can interface with it and test every injector and spark plug and get readings and all the switches and report showing everything normal?

I did not compare the Spark output to the working engine spark production . Not sure what would cause a weak Spark... I did see spark on the old plugs when I tested.

Hopefully tomorrow with new plugs :)
 
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