Ambiguous starting problems - 99 SAN

[mswitt1234]

I am new to this forum and realize there are a lot of threads on this already. I hope this is in the right place. I've got some starting issues and being a bit new and still learning, would like to see if others have input on my direction and thoughts. I got this boat last season. It is a 1999 Super Air Nautique with the EFI GT-40 motor.

When trying to take the boat out for the first time this season, it would not start. Initially, it was very clearly due to the batteries as the first attempt gave me the clicks. We did get to the point of it cranking but never successfully turned over. We tried to do a jump from another boat on the ramp (granted was an outboard motor) and I also tried to jump it with my truck in the driveway with a fake-a-lake. No dice. I get that this can be one of a few things (fuel, air, compression, wiring).

Initial Context: The boat ran fine when I purchased last season (late July 2022) and had it out 6-7 times. The boat was recently dewinterized with no comments from the shop, other than it was good to go. They have a place to drop boats in water, but keeping them on the trailer, and they start them as part of their dewint process. This is the last known time it ran, about a month ago. They also replaced the belts, water pump seal, and water pump impeller. The boat sat all winter with a full tank of gas and no trickle charging. I think the gas is non-issue, but the trickle charging almost certainly was an issue. However, I would think that would have affected the shop doing their work as well.

Other context

• Since getting it back from the shop, I installed a GPS speedo and depth sounder. The GPS speedo replaced the old tube ones and the depth sounder was new.
  • Both of these seem to work fine, nor do they appear to be drawing power with key turned off (even if ignition breaker is on).
  • The only thing I question here is the fact that I daisy chained the depth sounded off of the oil pressure gauge (not necessarily on purpose).
• There is a dual battery system the previous owner installed, which I believe is hooked up correctly
• Also since getting it back, I did some enhancements to how the batteries were placed and the routing of the wires. I did fully disconnect everything at one point or another but only to connect it all back up the same way.
• It now has a new battery, purchased at the marina near by, the day it would not start. So it now has a brand new battery along with the older battery. Same form factor and all but not sure if the cranking amps match (nor do I think that matters).
• All accessories still power up fine.
• When turning the key on, I can hear something start to buzz in the motor bay. I think it's the fuel pump but not sure.
• Sometimes when turning the key on, I can hear and feel a dual bilge system is kicking on but the bilge breaker is off.

What I've done thus far

• Ruled out dumb things like the lanyard, being in gear, etc.
• Did some volt testing of my batteries.
  • This part was odd. The boat's volt meter gauge was showing around 14 volts with the key turned on. My digital volt meter read around 10v on all my batteries. The old and new currently in the boat, and the old one we pulled out. Volt testing the positive lead on the new battery and the negative on the old, also showed about 10v
• Tried jumping if from my truck in the driveway, with both batteries set to "on", and also with just the new battery being "on"
  • Truck battery was reading 14v as expected when the truck was running, and the new battery started to climb, topping around 12.5v. I would think the boat battery should read 14v in this scenario as well.

My potential next steps

• Swap the spark plugs (skip testing as they should probably be replaced anyway)
• "Hot wire" the kill switch the lanyard attaches to
  • the motor sounds the same when trying to start with the kill switch engaged or disengaged.
• Look for any potentially bad ground (I hope it's not thais as it might be a needle in a haystack)
• Check the fuel pressure

My questions

• The check engine light in the middle of dash (not the "above certain RPMs" one) is lit up when turning the key on. I think this is normal?
• What is expected to happen in the motor bay with key is turned on?
• I now hear a beep when I turn the key on, but I think this is just the depth finder. Its the more stnadard Faria in hull model. The manual does not mention a beep upon powering on. Does this year of Nautiques have any sort of pre starting alarms, however?
• I believe the kill switch cuts off fuel so it's expected to try to crank, but will never turn over with kill switch disengaged?
• When replacing the tube speedos, would I need two replacements? I fully disconnected both tube speedos, but only added one GPS speedo for now.

In short, I think I clearly have some battery issues, as even a brand new battery was reading 10v after getting it back to the house. But I think there might be something else at play here. Any insight is appreciated.

[Jonny Quest]

You may also want to post this on the "other site" www.CorrectCraftFan.com. They have a lot of experts there on the older boats -- particularly on the GT-40.

[bturner]

A lot to unpack here. As always I'll chime in with my perspective but keep in mind this is only my perspective and how I would approach this. Others may do something completely different or think I'm nuts so do as you see fit.


Let's start with the basics. First I believe a quality meter over a gauge. If your meter is telling you 10 Volts that's the number I believe. That said your reading is only as good as how you hook up the meter. I like to do the "reduce to the ridiculous" method of trouble shooting when going after any issue on a boat, car, plane or anything else I haven't verified as correct. To this end I would do this with your boat as well. What does this mean? Verify, then fix the basics before moving to the next item. Aviod at all costs running in circles changing things until the first item is completely resolved before moving to the next item.

• Start by disconnecting everything going to the batteries, then measure the voltage on each battery. Now what voltages are you seeing? If you're not seeing 12.2 to 12.4 volts either the battery is bad or not charged. If the voltage is low try charging the batteries. If one or both don't come up to proper voltage, take them to an auto parts store and have them load tested. I'll repeat this as it's important, stop doing anything else until you fix this.
• Once you have the batteries at proper voltage next would be wiring. When I hear owner installed, was completely rewired by owner or anything like owner enhancements I get a chill up my spine. You could be a marine electrical master but most times.... nope. At this point I personally would be closely checking each cable for...
  • Condition - How was the cable made, are the ends in good condition, are there any signs of wear or corrosion? Check all the grounds at the block and buss bars for condition and tight connection.
  • Proper type - What kind of cable was used? Is it marine rated? Is it the correct size? What kind of connectors were used?
  • Routing - How was the cable routed? How long are the runs? Is the cable the right size for the length of the cable?
  • Proper wiring - Here's the real wild card. Are the batteries wired correctly? You can't guess here, they're either wired right or not. Check each wire pat and verify it is correct.
  • Switch condition - I'm not a fan of the 1, 2, both switch, i prefer an isolator as they work automatically and have less chance for stupid to happen. consider adding a Blue Seas "Add a Battery Kit" as part of this exercise. (https://www.youtube.com/watch?v=vPhD7fgYq3w) Switches go bad all the time either mechanically, electrically or boat. WITH THE BATTERIES BOTH DISCONNECTED, pull the switch and check continuity of the contacts in every position and mechanical operation of the switch.

This should keep you busy for a while if you do it correctly. Good chance you'll find more than one issue along the way. If this doesn't fix your problem at least you'll have eliminated stupid from the equation at the basic level and can move on to other sections.

Disclaimer.....
"All comments are the thoughts and opinions of the poster. I'm not a professional mechanic nor am I providing professional advise or console. Do your own research on any comments/suggestions I make and take ownership/responsibility for any actions you take as a result of my post. All demos were done by a professional driver on a closed course, your actual mileage may vary, items may appear larger or smaller in person." I think that covers it.....

[mswitt1234]

Thank you both for the insight. I will check with the other forum as well.

bturner, you make excellent points. Since I made the original post I checked the spark plugs, and they seem fine other than the gap is a little smaller than the .045 gap that is specified. Not sure how big a role the gap plays. I ended up breaking one while removing it so they'll need swapped regardless.

My next step will be your recommendation. Fully disconnect and do volt measurements. I may just eliminate the dual battery set up for now to keep it simple. Part of me thinks the old battery still in the boat may have a bad cell and was draining the new battery. I think volt readings would be normal even if there was a dead cell, but an auto shop load test can prove this.

[jpwhit]

My next step will be your recommendation. Fully disconnect and do volt measurements. I may just eliminate the dual battery set up for now to keep it simple. Part of me thinks the old battery still in the boat may have a bad cell and was draining the new battery. I think volt readings would be normal even if there was a dead cell, but an auto shop load test can prove this.

Often with an old battery, a cell isn't dead it's shorted. That happens because the crud that settles at the bottom of the battery is conductive. When it builds up enough to touch the bottom of the battery plates, it shorts out the cell. If you have a battery with a shorted cell in parallel with a new battery. It'll drain the new battery down to 10V very quickly and the engine won't start as a result. Each cell is 2V, so a shorted cell battery will typically be 10V.

[shag]

BT is righto on point. I would bet your cables are corroded inside. A cable can 'look' fine but have inside corrosion. If you can feel the cable 'crunch' when you try and slightly bend it in areas it's probably causing your conductivity to be poor.

[fsts2k]

Sorry if I missed it above but have you tried measuring voltage at battery terminals and then at starter? That might give you an indication of voltage drop between them... aka cable issue?

[mswitt1234]

Small update. I eliminated the dual battery set up, and volt tested the new battery while fully disconnected. It was reading around 12.5v when fully disconnected. This is the same reading after trying to jump from the truck in driveway, while still connected up in the dual configuration. I put it on a trickle charger (also while fully disconnected), and that brought it back up to 13v. So I think this rules out/fixes the initial battery issues.

I've also swapped the spark plugs for safe measure, but this probably doesn't make much of a difference in hindsight. However, if they aren't getting spark its not the plugs themselves, as those are all new. The motor would still start if, for example, only half were sparking.

After swapping the spark plugs and reconfiguring with the single battery, the motor is still unable to start. My next step is to re-evaluate the new speedo and depth finder I installed. Probably start with just disconnecting them and see where that gets me.

fsts2k, when volt testing the starter leads, what voltage should I expect to see?

[jpwhit]

When you try to start it, what's happening? Does the engine turn over but not fire? Or is it not turning over?

[mswitt1234]

jpwhit, it is cranking/turning but will not fire.

[Scooter G]

If I am tracking correctly here, you are making direction, from no crank, yes?
Comes down to the old adage, Air, Fuel and Spark, you need all 3.
Which one is missing?

[jpwhit]

You mentioned bypassing the safety lanyard switch? Have you tried that, if not that would be my next step.

If you try that and it doesn't fix the issue, have you tested for spark? I still prefer the old time method of sticking a screw driver into one of the spark plug wires and holding the shaft of the screwdriver about a quarter of inch of something that's grounded on the block. But a lot of folks are worried about getting zapped. In that case, you can use one of these.

https://www.amazon.com/Ram-Pro-Engin...xpY2s9dHJ1ZQ==

[Scooter G]

Nice find jpwhit. I went to use my old archaic spark tester the other day from who knows what decade, it was toast. I've been meaning to look one of those up for my list of rarely used tools, but nice to have when you need it.
I just stuck my tongue in the wire, I haven't needed hair gel for a week now...

[mswitt1234]

Scooter G, you are correct. For sure was having battery issues, but that seems to have been resolved in my eyes, and now it should be one of the main areas.

jpwhit, I have not tested for spark. I am a little nervous to do that with how cautious the manuals say to be with creating spark or open flame in the motor bay. Maybe I am overthinking this, but I think the product you linked would get around that concern.

My thought on targeting the garages next, is because that's what I touched since getting it back from the shop (other than re routing battery cables). If it's not something with those, I'll likely either try hot wiring the kill switch or really start to dissect the wiring for bad cables, grounds etc.

Question about spark plugs. These are certainly easier to replace, but I found it hard to get the socket 100% over the plug. I had two different sized sockets (meaning overall form factor, both were 5/8 socket size still) but neither quite got on there 100%. I would say they were still close as I was able to pull them out, put new ones in and get them tight relatively easily. Has anyone else had that issue however?

[Scooter G]

Hit the Auto Parts store for a 5/8 plug socket, designed for spark plugs, game changer. Throw it in the stash somewhere on the boat...
As long as your lockers are open and you have ventilation, you have very limited to no worries. If you open the cover and your eyes start watering from the smell of gas, then rethink that one please
I could be off, but I don't think your gauges have anything to do with the price of rice in the orient here (remaining politically correct).
Good luck man.