Need help troubleshooting engine starting problem

[SprockJohnson]

Hi all,

New to this forum but not new to jet boating. I have a 2006 Yamaha AR210 I bought new in 2006 and although I haven't had many problems over the years this one is turning out to not be simple to diagnose. I last ran the boat a week and a half ago and it ran great and had a thorough post run rinse out from the saltwater. Yesterday I went to put the boat in the water and the starboard engine would not start. The starter was turning the engine over, although slower than the port side, but it would not start. Here is what I have already done to troubleshoot-

1. The tank is full of new ethanol free fuel
2. The shifter/ throttle is in neutral and I have also swapped the connectors for the neutral switches back and forth between the two sides.
3. The kill switch has the lanyard attached and I have swapped the connectors back and forth between the two engine sides.
4. The cleanout hatch switches had already been bypasses a year ago but I inspected the connectors and splices to verify there is no corrosion.
5. All spark plugs were removed, inspected, and checked for spark and they all appear fine. They were just replaced a couple months ago and only have a few hours on them.
6. All battery terminals and cables for both batteries (one was added aftermarket) and the aftermarket battery selector switch were checked, removed, brushed with a wire brush, and reattached to the batteries and switch.
7. Swapped the connectors for the ignition switches to see if the other switch would start the engines. Port side still starts but same problem persists with the starboard side.
8. Both batteries are fully charged, voltages were checked and reading 12.6-12.5v.
9. Removed deck hatch and removed starboard side fuel pump unit, checked fuel filter screen which was clear, and re-installed. Fuel line was pressurized before removing and pressurized again after installation.
10. fuel is observed misting out of head when spark plugs removed.
11. Throttle body checked and servo functioning.
12. Attempted to start with starting fluid but no detonation.
13. Checked all fuses on starboard ignition module.
14. Checked voltage at positive starter cable and it read approximately 10.6v and engine rpm while cranking was somewhere between 350-400rpm.


Anybody have any ideas? I'm thinking my next step will be to swap the starters to see if that is the problem.

 

[Looper7]

So you have spark, and fuel when cranking?

 

[F.M.]

When you verified the plugs were getting spark, did you check each coil also?

 

[SprockJohnson]

Yes, fuel and spark. All four plugs were sparking when I removed them from the head, inserted them back into the wires and grounded all four against the engine on the front engine lift ring and cranked it over.

Also forgot to mention that I checked the air filter and it appeared fine and the mass air temp sensor.

 

[F.M.]

Loose/poor connection at ECU?

 

[SprockJohnson]

I checked all connectors and they appeared to be solidly clicked in place but I can check again. The audibly lower RPM's on the engine as it cranks over makes me think it is the starter, which is the original, or something is binding somewhere.

 

[F.M.]

How about the starter cables? Possible loose connection there?

My daughter's car wouldn't crank yesterday, no click, no nothing, so I knew it was electrical. Checked clutch switch, starter solenoid, fuses, and it ended up being a loose starter cable.

 

[SprockJohnson]

Hmm. Could be. I blindly felt the connector under the rubber boot when I was getting a voltage reading from it and it appeared tight.

 

[Looper7]

Did it crank slow with the plugs out?

 

[SprockJohnson]

Appeared to crank fine with the plugs out of the problem engine but I didn't do the same to the working engine for RPM/ sound comparison.

 

[Looper7]

If your checking the battery cable at the starter I would take it off and clean it then put a little dielectric grease on it for reassembling

 

[SprockJohnson]

I haven't removed the starter yet so don't know if there is corrosion on the cable or on the starter itself. Boat was used only in freshwater for the first 8 years but now is exclusively in saltwater now I'm on the FL gulf coast.

 

[Looper7]

I had a similar problem a few weeks ago and I wish I could say what fixed it but I threw everything I could think of at it and it did fire after 20 minutes of frustration possible foul language best of luck to you

 

[SprockJohnson]

Anyone else have a similar problem with low starting rpm's and a failure to start even with spark, fuel, and air?

 

[tdonoughue]

Did you compression test the engine?

Looks like you have tested all of the normal things (quite well, I might add). So I am thinking, if you have spark (ECU, coils, plugs all ok), fuel (seeing the mist, that means ECU, injectors ok), air (air filter clear, etc.)--the only thing left to my knowledge would be something like a stuck valve not allowing the fuel/air to compress enough to ignite.

 

[SprockJohnson]

Haven't done a compression test yet, but will if swapping the starters doesn't eliminate that as the problem. Is a stuck valve an all-of-a-sudden kind of problem or is there usually some kind of telltale warning sign?

 

[tdonoughue]

That one I don't know. I'm just trying to think what else could possibly be wrong that would cause it not to fire... And that is the only thing I can think of.

I would assume it could strike all of the sudden, if there was some debris keeping it open or something. But I have no direct experience there from which to draw...

 

[WREKS]

Did you try a little starting fluid?

 

[SprockJohnson]

Yes, tried starting fluid through the throttle body and no detonation. Just bought a compression tester yesterday to see if I can eliminate valves as the problem and found a brand new aftermarket starter on ebay for $68 so will try swapping that out as I think it will ultimately be the problem/ solution.

 

[SprockJohnson]

So, a little update- It would appear it is not the starter as I first jumped the starter directly from the positive post on the starter to the positive terminal on the battery. Same slow rpm from the starter and no start. I swapped the port engine starter with the suspected bad starter, even though I was now doubting it was actually bad, and the port engine starter behaved the same on the starboard engine. Slow rpms (300-400ish) and no start. The suspected bad starter worked perfectly on the port engine and it started right up as usual. I swapped cam position sensors just in case and no dice. Still replicating the same slow rpm's. Spoke to a friend who owns a boat repair business and he said it could be the jet drive causing binding so I removed it and alas, no change in the phenomenon and zero detonation. I tested compression on the first two cylinders and zero psi. I checked the compression tester on the other engine #1 cylinder and it read 170psi after the engine started. My "boat repair business" friend recommended I remove the valve cover and see if the cam shafts are rotating with the crankshaft as it is looking more and more like internal component failure. I'll try this tomorrow as I have the day off. Anybody have any other guesses or advice?