Low RPM's and Check Engine on Port Motor (2018 212x)

[RenoJetter]

So we were out today, running great (like normal). Decided to start surfing and suddenly got a check engine for the port motor. Motor still turns over, but idles about 900RPM as opposed to the normal 1200 RPM. Upon giving it throttle, the port motor would top out at MAYBE 2k RPM. Starboard motor running fine. I tried/checked the following.

• Checked the grate under the boat - clear
• Checked the impeller/driveshaft - clear
• Checked the nozzle - clear
• Disconnected the perfect pass throttle connections (basically taking it back to factory) - no change
• Turned off batteries, waited, turned everything back on - same result

We finally limped back and pulled the boat out of the water. On the ramp I started both motors to blow the water out like normal. The port engine definitely sound wrong. Checked the engine diagnostic screen and getting the following for the port motor.
Yamaha Diag 116
OBD Diag 52 1304

Warning Scrren:
Full Byte 0x1C
Check Engine True

Not finding much online except for diag code 116, which says "Throttle Valve Closed", but not sure how to remedy. Any ideas?

Thanks!

 

[Bruce]

How far are you from a dealer?

I hope not but worry it could be a timing chain. Catching that before a complete failure could be a big savings. I would want to check that before restarting the engine.

When were the spark plugs last changed? How does the oil look?

 

[RenoJetter]

How far are you from a dealer?

I hope not but worry it could be a timing chain. Catching that before a complete failure could be a big savings. I would want to check that before restarting the engine.

When were the spark plugs last changed? How does the oil look?

Hi Bruce,
I REALLY hope you are wrong about the timing chain. I did run the engine a few minutes on the hose at home this afternoon. It actually idles ok, around 1200 RPM now. But wide open throttle it will only run up to 2500RPM. I keep coming back to the code 116 which is for a closed electric throttle. That seems to make sense, almost like it's not getting enough gas.

To answer your questions, I haven't yet checked the oil or the plugs. The motor has about 125 hours on it and I last changed the oil at 100hrs. It seems like something electronic to me. Mostly because it ran perfect, perfect, perfect, then suddenly this. Luckily the place I store the boat is also a Yamaha dealer, so I'll drop it back off tomorrow and have them diagnose/fix it. Again, I hope it's not something like the timing chain, which I'm sure would cost me a ton. Because boats aren't already enough money!
I do appreciate you taking the time to reply sir!

 

[dan144k]

You could try swapping some parts from one engine to the other. See if the problems is a specific part. Like the throttle body or throttle position sensor.

 

[RenoJetter]

You could try swapping some parts from one engine to the other. See if the problems is a specific part. Like the throttle body or throttle position sensor.

That's honestly a solid idea. If I had more time on my hands (and it wasn't almost triple digits outside this week) I would do that. I dropped it at the dealer this AM, the mechanic should be tearing into it and diagnosing tomorrow, so i'll keep everyone posted once I have some info.

 

[RenoJetter]

UPDATE!! It took the dealer a couple of weeks to get into it, but after a few back/forth with Yamaha it appears to now be fixed. Yamaha had them run a compression test, which was fine, then ultimately asked them to swap out the spark plugs. They cleared the error code and it was running fine in the shop. We took it up to the lake last night to run it under load. The service manger came with me. The boat ran perfect, just like normal! So after all that, it seems @Bruce was right to ask about the plugs. I have 125hrs on the boat and have never changed plugs. That would honestly have been my last guess. I'm not sure how long those plugs are supposed to last, but going forward, I'm just going to put new plugs in every 100hrs. We'll take it up this weekend for some recreation and make sure it still runs fine, but it ran awesome for about 30 min last night!

 

[Mesa50]

Glad it wasn’t serious. Our Yamaha jet boats seem to eat up spark plugs. I’d replace them every 50 hours to insure trouble free starting, and running. They let you know when they need replacing by giving you a few (hard to start when hot) episodes. If you have to turn it over a few times, or for a longer duration when the engines get hot, it’s probably time to replace the plugs.

 

[RenoJetter]

Glad it wasn’t serious. Our Yamaha jet boats seem to eat up spark plugs. I’d replace them every 50 hours to insure trouble free starting, and running. They let you know when they need replacing by giving you a few (hard to start when hot) episodes. If you have to turn it over a few times, or for a longer duration when the engines get hot, it’s probably time to replace the plugs.

Funny you say that…..now I’m thinking back and we did have some starts that were more difficult than they probably should be. I actually noticed how quickly the engines turned over with those new plugs. Great feedback!! Thanks!!

 

[RenoJetter]

ANOTHER UPDATE on this one. We took the boat out yesterday and had the SAME THING happen again. Port motor check engine with Diag Code 116. After running through some tests on the diagnostic screen, and trying again, I was actually able to get throttle back on the port motor, albeit the alarm was still present. However I think I accidently stumbled onto a way to clear the alarm which was simply to cycle the motor on/off multiple times. With the alarm cleared, the boat ran normal the rest of the day. So the question is....what is causing this? And I think the answer has something to do with the Yamaha Wakebooster.
This has now happened 2 times. BOTH times it has been while surfing with the wake booster installed on the port side of the boat. Both times we had someone surfing and had to do about 8-10 tries while the person was learning to surf. (basically getting up, but not staying up for more than 10-15 seconds at a time). Both times we were transitioning to a new surfer, so we had stopped both motors, switched out people and started again. Wakebooster stayed installed on the port side. Fire the boat back up and boom, port side alarm.
So I THINK I can replicate this issue, which is clearly not the spark plugs. The odd part to me is that we've been using that wakebooster for several seasons with zero issues. When we go back out, I'm going to do some troubleshooting and put the wakebooster on the starboard side, see if i can create the same thing on that motor. Then try it again on the port side. Perhaps there is a Electronic Throttle issue on the port motor that is only manifesting when put under substantial load caused by the wakebooster? While I can't see how the wakebooster could possibly cause an engine issue, the coincidence is too much to overlook.

 

[Bearsar240]

Did you ever resolve this issue?

 

[RenoJetter]

Did you ever resolve this issue?

Not entirely. I’ve yet to have it happen a 3rd time. I did run the wakebooster on the port side last weekend, but it never happened during that time. I’ll run it again hopefully this month and try longer to reproduce.