Engine Issues

[Craig]

So we were out this weekend trying to get in as much boat time before the end of the season and an issue came up. We had been tubing (app 20 mph with rpm's varying) and had slowed to pick up the tossed tube rider. Once they got back in the tube I accelerated and noticed that the boat wasn't running normal. I first thought someone had left the ladder down as it seemed like something was holding it back, then looked down and noticed that the tach for starboard engine was at "0". The engine had died apparently while at idle. The engine fired right up and all seemed well. While attempting to accelerate while the motor had died we made it to app 15 mph or so when I noticed the difference. Both throttles were forward as well as the gates "open". This happened the last trip out (app 3 weeks ago) but only happened once and I disregarded it as bad gas or something similar as it never happened again that trip. This trip however the engine died several times while idling through no wake zones. It wouldn't start for several minutes while idling into the no wake zone for recovery. After letting it sit for app 15 minutes it fired right up and seemed to run normal. I checked the engine oil while on the water as I was afraid I had pushed water into the engine while trying to accelerate but didn't see any signs of it. Once we got it loaded and back home I checked the oil again for moisture and didn't see any signs, and then ran the starboard engine on the hose for several minutes with no issue. I've not pulled the plugs yet as I had to travel out of town the day after we went out. I plan on pulling the plugs and checking them as well. I had added "storage" amounts of sta-bil prior to the outing in preparation for winterization.
Any ideas you guys can offer or direction on what to check would be much appreciated. Plugs were changed the beginning of this season, but I will check them when I get home. The battery was topped off and tested good as well. Also, how worried should I be that I pushed water into the motor? I've not seen any signs, but can't help but to be paranoid. They should make some type of alarm when our motors die, because you can not hear it with dual engines. If it had an alarm like the depth alarm, you would certainly hear it.

 

[OrangeTJ]

I really doubt that you pushed water into the engine in that short time. I've accidentally done the same thing a couple of times with no ill effects. Regarding the stalling, I wonder if perhaps the idle on that engine is set too low. Not sure how you'd adjust it, though.

 

[itsdgm]

That's a bummer @Craig. Intermittent problems can be the hardest to figure out. Just when you think you've got it, it rears its ugly head again. Hopefully you can get this settled before you put the boat away for the winter.

A few things that come to mind would be:

1. recheck (exercise) all the safety switches. Do you think it's possible that a clean out hatch switch was triggered when you went to the rear of the boat? Maybe one of those is out of adjustment.

2. What was your fuel level? Is it possible that a fuel pump is getting weak and has trouble sending fuel at lower levels? I would think that you would have bigger troubles at higher rpms if this was the cause.

3. I think you could be onto something with the spark plugs. I know that the situation that you're describing is a classic case of bad plugs on my vintage of yamaha engines. Not sure about yours though.

4. Possibly a bad Coil? Again, I would think that you'd notice this at higher rpms, but it would be easy enough to just swap the COPS from one engine to the other to see if the problem jumps to the other engine.

5. Possibly a bad ignition switch? This would be hard to diagnose unless the problem gets worse. You could swap ignition switches from side to side by simply swapping the plugs behind the dash.

Those are the things that come to my mind. Without question, check the plugs and replace them and hopefully that gets you going. Keep us posted on your results.

 

[jetboater4life]

I have the same die at idle problem but on my port engine. Mine usually starts right up and if it doesn't it will on the second turn of the key. It doesn't always happen during a given outing so it hasn't been persistent enough to fix during the season. I plan on checking the YDS readout this weekend. When I did a plug change mid summer all the plugs looked the same except for one on my port engine. It looked wet when compared to the rest. I suspect it is related to the amount of gas entering the cylinder so maybe a problem with the fuel injector. Another clue for me is when I slam the throttle to pull up a boarder both engines hit 10k but then the port tach drops back a few 100 rpms while I'm planing out. Once at speed it seems to go back to just shy of 10k. I don't see this on the starboard tach.
My port engine plugs, notice the plug for the cylinder closest to the rear of the boat looks wet.

 

[Gym]

@Craig. I agree with @itsdgm's suggestions. I would add to that checking the air cleaner for dirt/oil. If none of his suggestions pay any dividends for may want to buy/borrow a YDS to see if there are any codes. Even if you have to go to the dealer you'll be better armed with info. I'm also leaning towards a fuel injector. The spark plugs should give you an indication of that. If so you may want to try an injector cleaner. Not sure if the 1.8's use separate fuel pickups/filters & fuel pumps but that may be another possibility. Start with the cheap and easy possibilitys first.

 

[twentiesforever]

@Craig , did you ever figure out the issue? Im seeing the same issue. The starboard engine died 4 times this evening. I had to dock only on one engine.

 

[Craig]

Not really as the problem was so intermittent. We went out a couple more times before the end of the season last year and it never happened again. I will tell you that I changed the plugs in the affected motor and ran two bottles of Lucas fuel injector cleaner through the boat (one full tank of gas). The last time we went out was in the fall to look at the fall colors and the whole trip back to the ramp I ran the motors at WOT. It never happened again and I can't tell you the exact reason why it happened the first time, only that it stopped after doing the above. Not sure if it mattered but that boat was a CARB boat, and we've since sold it. Hope this helps you, @twentiesforever

 

[Craig]

I will mention that the plugs I replaced did not appear to have any issues or obvious signs of a problem. I also rechecked the gap on all of the plugs and they were gapped properly still. Like you I researched the issue and the one thing that I keep reading is how these engines seem to be very affected by plugs, and how so many others on here have fixed their engine issues by simply changing them. Best of luck..