Engines start rough, cut out

[JWPrendergast]

When I start up my engines, they crank right up, then idle rough, then cut off. Both of em. After doing this 3 or 4 time per engine, they run fine for the rest of the day. Not sure if it has something to do with it sitting for a week or 2 without being run. Any ideas?

 

[Murf'n'surf]

Sounds like it's time for new spark plugs.

 

[jawsf16]

x2. I would look at spark plugs as well. One other thought, I had a loose battery connection that caused motors to run rough. Sounded like rocks in a can then would cut off, then would be fine for awhile. Happened to both motors as well. Might check the voltage.
Maybe tighten your battery connections and see if it goes away, if not then spark plugs next...

 

[itsdgm]

I second/third the above recommendations.

Check battery connections
Change spark plugs
And I'll add, exercise all of the cleanout switches and lanyard switch.

 

[Speedling]

Yup, sitting can let the fuel/water seperate, or let humid air get in there and rust the plugs. This is one of the benefit to fogging the engine (usually) since the fogging oil is meant to try and stop the rusting of plugs.
Pull a few and let us know!

 

[JWPrendergast]

Ive changed the spark (and oil) plugs a few weeks ago and it still happens. Even the old plugs looked like they were in good condition. I use non ethanol gas, and when its not, i use marine stabil.

Il look into the battery connections as i know there is some corrosion there. As far as the switches, what needs to be checked?

 

[Murf'n'surf]

From your statement, I believe your battery might be to blame. I would suggest removing the battery and take it to an auto parts store and have it load tested. Upon installation, cleanup all corrosion with a wire brush and sandpaper. Make a paste from baking soda and water and coat all connections. Let it sit for 10 minutes then wash off with water. Let dry and install battery.

How old is the battery?

 

[Speedling]

That they are correctly adjusted to be down when the hatch is down. You can tape something to them to keep them to eliminate that as an issue for now

 

[Evildwarf]

When I start up my engines, they crank right up, then idle rough, then cut off. Both of em. After doing this 3 or 4 time per engine, they run fine for the rest of the day. Not sure if it has something to do with it sitting for a week or 2 without being run. Any ideas?

Since our 242 sits for a couple weeks between outings I have noticed the same or similar with our motors. They both start but sound real rough for a few seconds, maybe cut off or keep running and smooth out. This all takes about 30 seconds to resolve then it's smooth sailing with no deficits in performance noted. Non ethanol fuel with stabilizer added, new batteries, connections good and clean. I will check plugs but anticipate no issues with them as they are also brand new.
I attribute the condition to cold weather and engines sitting for a week or more between outings.
Engines sound like hell though for a short time.

 

[txav8r]

Some of that is just normal. A cold engine, where the oil has drained back, takes time to relubricate and stabilize the air fuel mix as the engine runs...were talking seconds here, not minutes.

 

[JWPrendergast]

That's exactly what it does. Just want to make sure there wasn't something mechanically wrong going on here.

 

[Britboater]

Mine has recently done the same, ran rough and cut out twice, never done it when warm so I'm not too concerned.
My FZR however, would sometimes go into a rough idle and has cut out once or twice when warm and was difficult to start, almost draining the battery. I did change the plugs but I've only managed to use it once, so cannot comment yet.

 

[jcyamaharider]

Mine has recently done the same, ran rough and cut out twice, never done it when warm so I'm not too concerned.
My FZR however, would sometimes go into a rough idle and has cut out once or twice when warm and was difficult to start, almost draining the battery. I did change the plugs but I've only managed to use it once, so cannot comment yet.

We have seen this issue with the 1.8 liter boats while surfing. What we suggest to do to remedy the issue is run the exhaust fan. This gets the hot air from around the engines out and seems to fix the issue. Not an issue with the mr-1 engines.

 

[Addicted]

We have seen this issue with the 1.8 liter boats while surfing. What we suggest to do to remedy the issue is run the exhaust fan. This gets the hot air from around the engines out and seems to fix the issue. Not an issue with the mr-1 engines.

I have this same issue from time to time. There have been times when I wondered if the engine would start (has happened on both engines, but never both at the same time), and has always happened while hot. Only 10 or so times since new. I had not thought of the excess heat in the engine compartment causing this. Great tip, thank you!

 

[txav8r]

I have also had that happen on the 230, MR-1 while doing wake sports and tubing. High rpm, low speed, and repetitive starts while hot. I discovered too that running the blower during all this activity cured it. But I didn't put two and two together in this thread! Good catch @jcyamaharider ! It did do it on my MR-1 as well and I sure thought I had read a few threads over the years about that too...maybe not???

 

[octavio3311]

My engines would also do this when hot. More often, the port emgine.
Started running my blower - and that seems to have eliminated the problem.

 

[txav8r]

I suspect that just running for the 2 minutes before you start is sufficient. I pretty much tried to do that...but then you forget the blower and find it still on when you shut down the engines again! lol

 

[jcyamaharider]

I haven't seen this issue with my boat, not saying it won't happen, with full days of surfing. Guess I am just getting lucky right now.

 

[Evildwarf]

Took the boat out the other day for a short cruise in the afternoon sun.
Engines started rough ( I was expecting this) but neither engine smoothed out at all as we eased out of the slip.
They sounded worse than ever and as we began moving through the marina at no wake speed I heard the over heat alarm and realized I also wasn't hearing the cooling ports over my right shoulder.
That's when I realized I hadn't put the plugs in!
Moron.
I shut her down and seated the plugs, cranked the twins and viola she ran like the modern wonder of marine jet propulsion that she is!

 

[Cobra Jet Steering LLC]

Here is a couple of things to consider, with the 1.8 engines if the throttle is not completely back to the stop , the sensor will keep the ignition from firing so the thing will crank over but not run, I can't say if this is true of the mr1 engines but it is probably the same.
So if a sensor is acting up you can have an issue . Here is what I have found that causes issues with things running and operating correctly.
Keep in mind it's my personal experience and remedy.
I always rinsed off my engines after use even though they never really needed it. One day After rinsing the engines off I started the engine and had all sorts of issues even the low fuel warning but the tank was full. I then tried not rinsing the exterior of the engines just to see if that was causing a problem but I did coat them with white lithium grease .
This solved the issue . So perhaps you are getting your wiring wet and it is causing it to run rough for a while, just something for you to check. I actually sprayed inside all my electrical conections with silicon spray to prevent moisture from causing any issues , I know they are supposed to be water proof but it can't hurt. Any corrosion on a sensor pin conection changed the value and may cause issues so a ounce of prevention is a good thing.