Help! Port engine troubleshooting.

[MOA_Chaser]

My boat has been trouble-free for the past three years I've owned it.

This year, I've noticed that the port engine has been a ;ittle slower to start up than the starboard engine.

Last week, we had some trouble (forgot to put in the drain plug) and the engines got some water up around them, but didn't get up around the air intakes. It's been pretty damp in there and I've tried to air it out, I haven't seen any indications of water in the engines at all though.

We had some trouble getting the port engine to start when we had water in the bilge, but it eventually started. I got it home, checked the oil to make sure it wasn't waterlogged, dried it out, filled it with fuel and started it in my driveway a day or two later. It started right up, almost instantly. We went to the river today and it started right up. Success, or so I thought.

We drove about a mile downstream and decided to drift a bit, and shut off the engines for 15 minutes or so. When we went to start them up, the port engine would not start at all. The starboard engine, though, would start right up instantly. While it was running, we'd try to start the port engine... it would crank for 5 seconds or so and then the starboard engine (already running) would shut off. We tried this for a while, and with the same results each time... port engine wouldn't start; starboard engine starts instantly, runs fine, after a few seconds of trying to start the port engine the starboard engine shuts off. But then the starboard will start right back up again.

We ended up going back up the river a ways at no-wake speed (to avoid getting water in the non-functioning engine). We dropped anchor, as we knew we could get back to the dock in plenty of time before dark to enjoy some of the day. After about a half hour at anchor (and occasionally unsuccessfully trying to start the port engine), we tried it again and the port engine started right up. We went further upstream and anchored for a while. We were able to start both engines to get back to the launch. We went back and docked up to the launch to get the truck/trailer, but ended up using only the starboard engine to trailer the boat as the port engine wouldn't start AGAIN!!!

This boat has been bulletproof for us up until now, and this really concerns me. It's always the port engine. What can I check to make it more reliable? I changed the spark plugs before our first trip this year, three weeks ago, and changed the oil at that time too.

Any ideas? I don't think it's vapor lock as we had this type of trouble when we had it out when it was 68-70 degrees last week and the engine was still having trouble starting...

 

[Murf'n'surf]

Sounds like you need a new battery.

Do you have one or two?

How old is your current battery?

Did you keep it charged over the winter?

 

[davel501]

Sounds like a voltage issue. Check your connections on the batteries.

 

[MOA_Chaser]

I have two batteries, all maintained over the winter and tested out fine. I'll look at all the connections between the battery and the port engine though, that sounds like a good start. My batteries are a dual purpose starting battery coupled with a jumbo AGM DieHard battery. Plenty of CCA and reserve. I had switched the batteries between attempts with no change in behavior, as well.

 

[txav8r]

Not sure I would jump to battery. The starboard is starting each time and no mention of long or slow starts. During the water in the bilge/engine compartment, the humidity in your intake is substantial, and that certainly can cause issues. But it would affect both engines. Having an engine be finicky, isn't unheard of, but finding the reason is important.

Remember, if an engine turns over, but won't start, check the following and eliminate those things that would cause the same problems on the starboard engine.
Kill Switch
Fuel Tank-water or pressure
Spark Plugs or caps
Crankcase filled with fuel/water
Fuel filter clogged or water filled.

So...Kill switch...could be the kill switch, tape a dime on the clean out hatch over the kill switch (it may not be the left one)
Fuel Tank...would affect both engines so that is not it.
Spark Plugs or caps...certainly could be.
Crankcase filled with fuel/water...well, you would see milky oil, or have other issues developing but since you did fill the engine compartment, I would pay attention here too.
Fuel Filter...you may need to check it if the other things don't result in a cure. The easy cure and often culprit is the spark plugs. I would change them and see if you get back to normal, if not, move on. I am not following the voltage or battery here, not sure what the other guys are seeing that draws them to that...if one engine is continually starting normally and the other isn't, how could that be voltage or battery related...he didn't say it was weak.

EDIT...I got off track on this one. The "Kill Switch" is the lanyard, not the clean out tray. The "lanyard kill switches" will prevent the engine from starting, but NOT prevent it from turning over the starter. The clean out tray kill switches prevent both rotation of the starter and block the ability to fire the engine...both of them. So disregard the clean out tray.

 

[txav8r]

But it could be a bad connection to that engine from the battery. But not if it is turning it over good.

 

[MOA_Chaser]

It's turning over just fine, and strong. I cut it short so I don't burn out the starter. Plenty of cranking power.

 

[txav8r]

Try changing the plugs. Just looking at them could be telling. A number of guys say that high humidity conditions and recent runs cause similar issues. Have you tried this with the blower on or off? Turn on the blower before you try the start, it could be vapor lock. But I am going to double down on the plugs. On second thought, I think the sound system is grabbing all the power! sorry, I am being an and loving your signature sound system! Remember, I am without adequate tunes!

 

[MOA_Chaser]

Haha, I'm without the great sound for now, the WetSounds are off the boat, the replacement drivers are due to be delivered tomorrow! Been running with only the speakers in the tub!

I hate to think that it's the spark plugs, because they're all fresh with maybe 3 or 4 hours on them, max!

I have been keeping the engine compartment open when I can and running the blower for several minutes before launch.

 

[txav8r]

Scratch both of those then. I'm at a loss if it doesn't hit on that, move on to clean out hatch kill switches, and then fuel filter..

 

[txav8r]

Just remember, one bad plug (or misgapped plug) can cause it to be hard to start, add a little carbon due to improper burning (because of gap), and it won't start. Just a thought here. Did you check the gap on all of them?

 

[MOA_Chaser]

Fuel filter sounds like a great idea and probably due anyways. I'll take a look in the morning.

Also, no, I didn't gap my plugs. I'll check that too.

 

[txav8r]

As they say..."mind the gap"! You should check the gap on any plug you buy. The old saying that it come pre gapped is all BS. Yes, they do, but they also ride around in a box with a little cardboard cylinder to protect the gap...and they don't. Check those gaps on every install! Hope that is it, but may not be...but you gotta know.

 

[Gym]

I would consider swapping plugs & coils from port to starboard. If the problem moves then you need to determine if it's a plug or coil issue. One thing that puzzles me is the starboard engine quitting when the port engine lights off. That would indicate a safety switch issue as @txav8r suggested.

 

[davel501]

The thing that put me to electrical is the one engine died while he was trying to start the other. That happens with dead batteries. Here the batteries are known to be working so that seems more like connections or maybe a bad starter.

 

[txav8r]

That is a consideration in the diagnosis...and admittedly, I kind of streaked past the port dying when starting the starboard. I noticed I mentioned above about the clean out tray...it isn't those. It would be the lanyard kill switches, because they will allow the engine to turn, but not to start...the clean out tray switches won't let it turn either. My bad on that one.

 

[Boat Crazy]

I am going to go a different way on this and say check your air cleaner on the down engine. You may have gotten moisture in it. Remove it and try to start engine.

 

[txav8r]

@Boat Crazy , good point and agree with that. Since it was just serviced, it could be too full on oil too and that filter may be splattered a tad...after it runs a bit, it gets worse. But that doesn't explain shutting down the other engine when trying to start the failed one.

 

[Boat Crazy]

It could also be your plug inspection cover switches may need to be adjusted. The port switch may need adjusting, and when you try to start it bounces the lid enough to shut down other engine. Worth a try to tape 2 nickels on hatch above switches, close lid and try both engines. It will not take long to rule this out. The port side switch may or may not be for your port engine.

 

[txav8r]

@Boat Crazy , I thought this at first too. But if the clean out hatch switches were causing it, the engine would not turn over at all, and his does. Each switch is a break in both spark signal AND starter signal, so if they were causing it, the engine would not turn. I said this earlier in the thread and corrected myself...it would be the lanyard kill switch that might be causing it.