Both engines, excessive vibration and stall out.

[FSHER]

Good day,

I’ll jump right into it and apologize in advance for the longwinded post. This is in regards to engine stalling issues that happened yesterday.

I think I have an idea of what is going on but I’ll keep it to myself to see if I’m close.

I have a 2021 Yamaha FSH 210 with twin TR1 engines based out of clearwater, FL. I keep it covered on a lift.

Last week I changed out the engine anodes and changed the oil and filters as well as the air filters.

The anodes absolutely sucked and I ended up taking the intakes completely off. I ran the boat after that for an hour or so and everything went fine. At that point the fuel was at 90% full.

I fill the boat with pump gas and never let the tank get below 70%. The past few months I’ve had the boat out maybe 3 times and only burnt maybe 10 gallons in total.

This weekend we did some idle cursing for about 45 mins and then bumped it up to 5-6k rpms for 30 mins or so.

The port engine dropped to around 4k rpms, stumbled, vibrated, pretty bad and ultimately shut down. I turned off the starboard engine and gathered myself. The boat leveled off and I was able to start boat engines just fine. They idled just fine but when I advanced the throttles they both got to around 4K and the bow was pointed to the sky and they both ultimately stalled out. Thinking it was a fluke, it tried again and was met with the same results. So, I called a tow.

No overheat warnings or any other warnings that I saw on my screen.

When I got back to the lift, I did notice the fuel was at 40%. This tracks because we had a long day of driving around.

I put the boat on the lift and connected my flush hoses to each engine. They both started just fine and idled as usual. I bumped the throttle and they seemed to react normally as well.

The only thing I noticed was that the port engine did sound slightly lower in tone out of the exhaust. But I’ve never paid that close of attention to it, and it was very slight. Perhaps it was because I had the boat very low on the lift and the sound was bouncing off the dock. Typically, I’ll flush them with the boat all the way up on the lift.

Curious of your thoughts,

-Mark

 

[Hot2Go]

Pull your clean out plugs, bet you have something or many things stuck in your impellers. If it’s on a lift I assume you can get under it to look through the intake grates too.

Vibration and loss of thrust/power is common when you’ve sucked something up in the pumps.

 

[Neutron]

Pull your clean out plugs, bet you have something or many things stuck in your impellers. If it’s on a lift I assume you can get under it to look through the intake grates too.

Vibration and loss of thrust/power is common when you’ve sucked something up in the pumps.

But that doesn't explain why they shut off

 

[FSH 210 Sport]

I assume that everything was totally normal before you did this work?

 

[TeeNGee]

I vote for over filled oil during oil change.
During acceleration, the oil in the sump sloshes aft and gets frothed up by the crank possibly getting into the crank case vent and then into the intake causing the engine to quit.

 

[FSHER]

Pull your clean out plugs, bet you have something or many things stuck in your impellers. If it’s on a lift I assume you can get under it to look through the intake grates too.

Vibration and loss of thrust/power is common when you’ve sucked something up in the pumps.

I hear you but this was different feeling. I was a very weedy day but I've never had engines stall due to weeds.

 

[FSHER]

I vote for over filled oil during oil change.
During acceleration, the oil in the sump sloshes aft and gets frothed up by the crank possibly getting into the crank case vent and then into the intake causing the engine to quit.

Damn, I'm thinking you may be onto something with this one. I'm not that nonweldable about how the system works but that'll be my first troubleshooting point. remove the intake tube and inspect. when i opened up the engine compartment my wife even mentioned that it smelled funny. she said it didn't smell like fuel. also youre explanation may make more sense because of the expantion as the oil warmed up?

i had a hell of a time replacing the anodes and by the end of that job i was totally done with the boat and thought about pulling the drain plug and pushing it off the lift. my hands and arms are finally healing from all the cuts and burses.


my thoughts were related to fuel. turns out i missed all those conversations about how bad ethanol is and I've been putting that mixed crap in the boat for 3 years now. my father failed me, again. i let the fuel level get lower than i like it to be so i was thinking, water may have been at the bottom of the tank and was able to find its way to the pumps due to being low.

or i thought about a faulty fuel sending unit, maybe it was reading higher then it should and when the bow was up the fuel pumps sucked up air?