Ambiguous starting problems - 99 SAN

[mswitt1234]

Another update.

Just had to find a better wrench for the spark plug socket fitment, all good there. Re-pulled them to make sure I didn't mess anything up the first time, and also to add some anti-seize (not that I expected it to improve the situation).

Took out the gauges I added, and used an inline spark tester when trying to start up again. Sparking looks fine as far I know. The lightbulb in the tester lit up, and at a regular interval. When pulling the old, and re-pulling the new spark plugs, they had gas on them. I think this means my gas supply is fine.

I noticed the ground connection for the engine block, to the frame, was very dirty. I cleaned that up (maybe not as best as I could though).

So to this point, the battery is good and appears my gauge install is not the culprit. It seems like I am getting fuel and spark, which really just leaves the air component. Could it also be possible that the computer went bad?

For the record, and if this helps, the motor does have pretty high hours. Over 1000.

[Tom_H]

Just because you're getting some fuel doesn't mean you're getting the appropriate pressure. Is it coughing at all, or just cranking? And did you ever bypass the kill switch to rule it out (crank with no fire is exactly what a failed kill switch will do)? Might be time to get a fuel pressure gauge hooked up and see if it's pressuring up at key-on and if it's maintaining it while you crank. There's quite a few things in the GT-40's fuel delivery that can go wrong. Also, have you made sure the breakers back on the engine aren't tripped?

[jpwhit]

Couple of thoughts.

One reason I prefer the screwdriver spark test, is because you're actually making a spark. The test lights will still light most of the time if the ignition voltage is low, so only making a really weak spark. The brightness of the test light does give some indication, but that only really helps if you have used it enough to have a point of reference. I guess you could attach the test light to a car or something that's actually working at the moment.

Are you sure the plugs are wet with gas and it's not water? I've seen plenty of no-start issues turn out to be water in the tank that finally got up to level of the fuel pickup. I have an auxiliary fuel tank setup I use for diagnosis fuel system problems. It's basically an outboard engine gas tank with its owns fuel pump and adjustable fuel pressure regulator. Another trick you can do to fairly reliably rule out an insufficient fuel issues, is take off the spark arrestor and spray a couple of 1 second bursts of starting fluid spray into the intake. Then try to start it within 10 seconds or so. If it fires and runs briefly off the starting fluid, then that proves you have a fuel issue.

And as Tom_H suggests, attaching a fuel pressure gauge is a good idea and gives very good info. If the pressure is too high, then the engine may actually be flooded. If it's too low, then there won't be enough fuel. I'm not exactly sure of the pressure for a GT-40, I would guess it should be in the 40-50 psi range. But maybe someone that knows for sure will comment.

Also, not a bad idea to check if there are any engine codes stored in the ECM. But that does take a marine specific code reader. I use Rhinda Diacom and a computer.

[mswitt1234]

Tom_H, yeah I am starting to rethink that my fuel is okay. There is gas in the cylinders, but start up sounds the same with the kill switch engaged vs disengaged. You hit the nail on the head on my next steps. I was going to check full pressure and the replays/breakers.

jpwhit, good idea on the baseline test for the inline spark tester. The first light up is brighter than the subsequent ones. I have a video of it I may upload here soon.

I'm starting to get over my fear of fumes so I may also do the screw driver method or hold the plug against the motor to ground it. I also like the idea of the starter fluid test.

To the best of my knowledge, it's gas on the plugs. It's not exactly clear like water and certainly smells like gas, but I doubt that is conclusive. Can 99 year Nautiques return engine codes?

[jpwhit]

Tom_H
Can 99 year Nautiques return engine codes?

That's a very good question, I'm not 100% sure. I do have a 98 Ski Nautique sitting in my lake house garage with a GT-40 sitting in it. But I haven't started restoring it yet and it currently doesn't even have a battery in it. Maybe later this week, depending on how other project go, I'll throw a battery in it and connect up Diacom and see what happens.

Maybe someone else with more experience with the GT-40 can comment if the ECM stores codes or not.

[Tom_H]

I think the GT-40 will store some codes, but takes a specific reader to grab them (not sure if a Rinda will connect to it). There's not a lot of feedback from the engine to the ECM beyond oil pressure, temperature, etc., so short of a bad ECM screwing things up, not sure if trying to pull ECM codes will really help anything.

msswitt, you said the start up or lack there of is the same with the kill switch engaged and disengaged. If your kill switch is bad, it will crank in both scenarios but not fire. You need to short across the kill switch's wires to test it (or check continuity with kill switch on and off to verify it's working).

[Scooter G]

If the kill switch was toast you wouldn't be getting spark, am I wrong here..?
I like Jpwhit's starting fluid idea, a little goes a long ways here.

[mswitt1234]

To the best of my knowledge, the kill switch cuts off fuel. I am not sure if that means spark too.

I did the hot wire test and doesn't really seem all that different. When tracing the wires of the kill switch, I noticed there was a butt connector along the way for each wire coming from it. They were an older style connector, that was basically just crimped, bare metal with cloth to shield. Not convinced that would be an issue but worth updating regardless.

Here is a link to the video I mentioned regarding the inline spark tester. https://photos.app.goo.gl/UvqPEdP3VME2UDd78
It shows two attempts, and the key was turned off in between. What is interesting is the sparking seems to be stronger the second time. The other thing I'm curious on what others think; The audio of this video has what sounds like the fuel pump kicking on, but then off very quickly. I thought they were supposed to prime for 2-3 seconds.

I still need to do the baseline test of the inline tester, and also will start doing fuel pressure testing. There seem to be common issues with the pump itself and the relays, and that would make a bit of sense regarding how coincidental it would be.

[Scooter G]

mswitt1234, just a nerdy observation from your video. In your 1st attempt you had 4 full engine rotations (video played @ 1/4 speed) and only one hot spark. In your 2nd attempt you had 3 full engine rotations and 3 hot sparks. The hmmm in me would say I am going to try that on another plug to see if I get the same results. It would sure be nice to see if you are storing any codes... It would be interesting to see what that can of start juice does?

"I love the smell of Ether in the morning, it smells like, Victory!" ~Apocylpse Now

GT-40 Service Manual.pdf

[Tom_H]

If the kill switch was toast you wouldn't be getting spark, am I wrong here..?
I like Jpwhit's starting fluid idea, a little goes a long ways here.

The kill switch interrupts the run signal off the ignition switch (i.e. power to the fuel pumps). When you turn the key to crank, you'll still be sending power to the starter to turn (it's a separate wire off the switch), so yes, the kill switch cuts off fuel but not spark (I would expect to not hear a fuel pump prime though if it's the problem - . The neutral safety switch, however, will kill spark and you'll get no crank in that scenario. That's why I recommended just bypassing the switch to make sure it's ruled out as a problem or not, given the stated behaviour.

mswitt, in your video it does sound like the fuel pump for a second, and it does sound short, but if you'd been doing a lot of starts, it may just have still been mostly primed - but you won't know if it's an issue until you hook up a pressure gauge. Starting fluid would at least give you an idea though, and could more or less rule out the spark side if it fires up.

[mswitt1234]

Scooter G (and all),

I had to step away from diagnosis for a couple days to get ready for an upcoming trip. It may not be until late next week that I can come back to it. It's turning into a bit of a rat's nest, but in a much better state of diagnosing at least. I do want to try all the suggestions. I'm a bit clueless on trying to get back any codes may be getting stored, however.

This is the point I am at:

• Battery issue eliminated
• Kill switch hotwired
• not related to my new gauges

Newer developments.

• Fuel pressure testing
  • key on, engine off - initially read 30 psi. A few turns of the key brings it up to 40. While this is not ideal, likely not a major concern for the immediate issue
  • however, I was checking the pressure the next day, and I am no longer getting any pressure. I figured maybe the gauge broke, but no gas came out of the hose when disconnecting, like the previous day.
• Replaced fuel pump relay and ECC relay, no dice.
  • I figure this was an easy thing to rule out. Question here however, I did this because the old relays seemed to be acting...odd? (to me at least). When key is turned on, one of the relays clicks twice, while the other only clicks once. When key is turned off (after being on), the single clicking relay, clicks a second time.
  • There appear to be two other relays, or at least I think, doing something with the motor bay hatch actuator among other, currently unknown things. The actuator actually started to act up just the other day so I'm thinking of replacing those as well. It would go up, but not come down. I found that "fidgeting" with wires on these replays, the actuator would lower itself again.
    • they have the same exact posts and stuff as the FP and ECC relays, but they are a different "style." I will try to get a picture for reference.
• Motor breakers.
  • I have the push button breakers like most others have I believe. Question here is if the 60 amp breaker is naturally longer (meaning it sticks out further). It is currently sticking out further than the 15 and 12 1/2 breakers. I tried to push it "in" but was not sure if was already pushed "in." I was trying to push harder than I would have thought, if it really was tripped.

My next steps (in no specific order)

• test more than just the one spark plug
• test with starting fluid
• look for stored codes
• replace fuel filter
• test relay resistances
• start to consider this being a bad computer - There's seems to be a wealth of info out there on testing the pins on the connector. Hopefully it is not this.

[mswitt1234]

So I started with the path of least resistance (in my mind) and "started" to swap the fuel filter. I figured this was needing done anyways as I have no idea when it was last replaced, and highly doubt the previous owner did anything with the motor. He had it for one season and only updated audio components to the best of my knowledge. For what it's worth, he only had it for one season because he ended up finding his dream boat shortly after buying the Nautique.

"Started" is in quotes above because I've got the classic seized (or extremely tight) FCC issue. I ended up taking the whole unit out and plan to "get angry with it" (vice, pipe wrench, chain wrench, heat, whichever works).

While it's become a pain to make a simple fuel filter swap, this is a bit of good news for diagnosis. This all suggests that the FCC as a whole has been neglected, and hoping I just have a clogged filter (or maybe bad pump).

[mswitt1234]

Good news! Boat is running...but rough.

I swapped the fuel filter and really didn't expect that to be any sort of help after I had my eyes on the old one.

Starts up strong then gets very weak. I can see why this is happening but not sure where to go with it. Fuel is leaking out of the FCC and appears to be coming from the power connector. Anyone have any thoughts on that?

[mswitt1234]

Actually, the fuel may very well be coming from one of the top hoses leading to/from the fuel rail. These felt tight but maybe I need to snug them up a bit more.

*Edit: Nope, not coming from fuel rail lines. Definitely coming from that electrical wire hole. Going to take the FCC out again and inspect it.

https://www.planetnautique.com/vb5/f...rance-into-fcc

https://www.planetnautique.com/vb5/f...u-retrofit-kit