2007 VZ250TLR not starting.... on the ramp :|

[spinkick63]

Ok Yamaha gurus... tell me what I am missing here.

I have a new-to-me 2007 Skeeter 20i with a 2007 Yamaha VZ250TLR. I don't think the original owner did much maintenance so I skipped ahead on a few things:

1. Replaced both low pressure pumps
2. Removed/cleaned VST and replaced the internal filter (no evidence of water, was reasonably clean)... did NOT replace the high pressure fuel filter... seemed ok
3. Replaced 8 of the 10 basket "mystery" filters. All were actually in good condition so I'm sure the other two I couldn't get to are likely in same condition
4. Replaced primary fuel filter and cup... previous individual stripped the plastic theads. That filter was rather dirty.
5. Removed and cleaned the fuel injectors
6. System primed normally
7. Replaced the starting battery

There's probably a couple more maintenance things I did, but I cannot recall them right now.

Last night in the driveway, I hooked up the water and cranked the engine. It cranked right up. I let it idle for about 10 minutes. I pushed the throttle forward (still in neutral). Was concerned about the obvious miss until I remembered #3 and #4 don't engage until in gear. Wiped that sweat away. I put in forward at idle then reverse at idle. All sounded fine. Both 25 gallon tanks are over half full. Ready to go.

This morning I head out to the lake and get on the ramp (typical angle) AND IT WOULD NOT START!!!!! It turned and turned and turned over, but would not start. Confused, I started checking on things. Primer bulb was not flat, so I gave it a squeeze. Could only give it a little squeeze because it was pressurized. Motor was all the way down. Batteries were engaged (switched). Kill switch lanyard was in place. Power was enabled on the dashboard. Would not friggin' start so I had to pull it out and take it home.

When I got it back in the driveway. I did nothing but remove the cowling and turn on the water. IT STARTED IMMEDIATELY without any hesitation?!?!?!?!?

WHISKEY. TANGO. FOXTROT.

What could possibly be the deal? Will try to examine the gas in the tanks, but when I pulled the VST, there was not water contamination that I could tell.

One suggestion on BBC is potentially exhaust tuner. After reviewing service manual and massive searches, I don't see "exhaust tuner" as part of this engine. Can anyone narrow it down a bit?

Thanks in advance.

[spinkick63]

Didn't see a way to update my post. 10 micron fuel/water separator was also replaced.

[99yam40]

I have no clue what happened, but you need to find out if it has spark to any plugs when it does not start.

removing the cowling may have moved some wiring around.
just something to look for.

[robert graham]

Was your emergency cut- off tab in place at the ramp? …..

[spinkick63]

As mentioned in my original post, he kill switch was in place and never touched. I pulled the lower unit off and looked at the exhaust passages in both the bracket unit (muffler and manifold) and the lower unit. Looks like I would expect them to be.

Any mechanics feel free to point anything I got wrong.

I did notice the muffler gasket needs replacing but I can't imagine that being the issue. However, I was wrong once before on a Friday.

[robert graham]

So you”got back home and removed the cowling and it started right up”…..maybe check air intake passages on cowling for bird nests/ wasp nest, any obstruction?

[spinkick63]

Zero obstructions. I opened up the throttle for the picture. Silencer/baffle (whatever it is called) was clear of obstruction as well. Head scratcher. All connections are secure and essentially immobile.

Unfortunately, without being on the ramp, I can't emulate the angle the motor was at in the driveway, if that was a factor.

As for the cowling, the night before when I did the start up, it was with the cowling on. In the morning before I left, I remembered the VST is missing a grommet (on backorder) so I put in a temporary brace (small hose clamp was right width). I pulled the cowling off to make sure that clamp didn't interfere with anything. Clearly, it wasn't a factor.

Have any idea of the purpose of the damper seal? Clearly, it is damaged and I have ordered a replacement. However, other than just keeping exhaust in the right chamber, what do you think the effect of a leak there would be?

[spinkick63]

Ignition switch and kill switch tested. Works as expected. :|

[99yam40]

has it started every time since the problem at the ramp?
if so take it back to the ramp to see if it repeats ,so you can chase spark or a fuel problem

you need to know if the rail pressure is in spec, injectors working, and spark is happening when it does not start

[spinkick63]

I've only been to the ramp twice with this boat (did lots of maintenance and had to wait on parts). First time, it started perfectly. I backed off the trailer and pulled into a slip w/o issue. However, the engine died as I got to the slip. No big deal. I tried to restart. Battery was too low to turn it over so it got replaced. It hasn't started on the water since.

I know injectors are working because I pulled them all and cleaned them. And, it has started every time in the driveway. Next step is to get a big bucket or tub to start up in the driveway as it would be on the lake.

It is acting like a kill switch issue. On the boat I traded for this one (had a mercruiser), it would not start at the dealership. I replaced fuel pump and oil pressure switch and diagnosed the wiring from ignition to harness connector. Turned out one of those bozos accidentally PARTIALLY tripped the kill switch (toggle type). You couldn't even see it. Pushed switch up and problem went away. Now I have this problem.

So, current goal is to trace the kill-the-motor wire on the motor. I'm guessing it goes to the ECM. My luck couldn't get any better.

[99yam40]

until you prove spark or fuel is a problem, you are just guessing.
ECU may not call for injectors or spark if it does not see the motor is trying to start

[spinkick63]

I understand your point. However, in the driveway there's been 100% spark and fuel flow. On the water the behavior has been kill switch engaged (based on previous boat incident). Regardless, no one has been able to point to a solid issue. So far... I'm on my own.

[99yam40]

need to repeat the problem so you can troubleshoot

[spinkick63]

Yep. Trying to get it to fail in the driveway. Need a big bucket or tub to emulate the launch.

[spinkick63]

Update for anyone following... I called Yamaha customer relations and explained the behavior and what I have done so far. I have done everything the rep would have suggested so he talked to a colleague. He came back and said it sounds like an exhaust obstruction. I would agree 100% if I could see one. The pathway is clear as far as I can see.
Before pulling the powerhead, I'm open to ideas once again.