NOT another timing chain thread Thankfully!!

[RadioWaves]

I know I should probably post this on a waverunner forum but I am not a member of any and you all know these engines well.

I have an '11 Waverunner VXS with the 1.8 and 100 hours. Last weekend We used it a lot and had no issues, it sat in the water overnight and in the morning I was going to load it on the trailer, tried to start it and it turned over slow a few times then backfired loud! Tried again to start and it fired up and seemed to run good. Idled out of the cove for a few minutes then it started running rough and shaking, then died. I had to swim it to shore and tow it to the launch.

First thing I thought of was the dreaded timing chain issue, but pulled the cover and it looks good. got it up to the house and put the battery charger on it and after a couple of hours tried to start it again and it fired right up and idled normally. Let it set for another few hours then hit the starter again and it started but idled rough.

I know the first thing to try would be new plugs, even though I just put new in this year. Any other ideas? To me it acts like it might have jumped time but not sure if that is even possible on these engines

Thanks in advance

 

[Scottintexas]

let me start by saying " I don't know that answer" , I might think maybe you have bad fuel or maybe you have an injector that is sticking open dumping extra fuel (the backfire), I'm guessing you don't have a YDS, it may be worth buying one,

Do you see any smoke? how long are you running it on the hose for testing ?

.

 

[RadioWaves]

Thanks for the reply Scott, I don't have the YDS unless it is the same for the older 1.6l that I had in my '05. Otherwise I will buy it.

There was no smoke and I only ran it for a few seconds out of the water with no hose (cant find the hose adapter).

It is a good idea to get the YDS though

 

[buckbuck]

Back fire is highly unusual for these engines. I think @Scottintexas may be on to something about a fuel rich issue. check all your coils that they are firmly connected to the plugs.

 

[RadioWaves]

I will double check the coils, install new plugs and see how it goes, thanks

 

[tdonoughue]

When you pull the plugs, give them a good inspection. Any of them unusual? Greasy or burned, etc.? That can give keys to misfire issues, too.

 

[RadioWaves]

I did inspect the plugs and they looked brand new

 

[tdonoughue]

@Scottintexas , honest question here, but if the issue were a stuck injector, would he not see a wet plug on removal? And probably smell gas. And likely it would not look normal or brand new.

That said, I don't have a better idea yet...

 

[RadioWaves]

The plugs were defiantly dry, I hope it is just a bad plug but I'm sure that is a long shot. I have never seen one just go bad.

 

[Scottintexas]

@Scottintexas , honest question here, but if the issue were a stuck injector, would he not see a wet plug on removal? And probably smell gas. And likely it would not look normal or brand new.

That said, I don't have a better idea yet...

I don't know, I'm just guessing with the back fire and rough running,
Maybe if it was just starting to go bad and only occasionally staying open???

Also i wouldn't discount some bad gas

 

[Ronnie]

I think it’s a bad coil or a broken/cracked spark plug.

 

[fireflymedic]

I had a motorcycle that would run roughly and back fire with old gas. I had about half a tank so filled it the rest of way with new. Help some but not muck. Had to get rid of all the old gas. That and a healthy dose of seafoam.

 

[RadioWaves]

It will be 2 weeks before I get back to it but I will update with what I find, just glad it's not the chain!

 

[Gozills]

Low voltage either bad battery or faulty charging system

 

[RadioWaves]

I wondered if low battery would cause this but I have had Yamaha boats since '04 and have had low batteries before but never experienced this problem

 

[Gozills]

Likely the older yamahas did not utilize the current multiplexed electrical sustem.

 

[RadioWaves]

Finally figured out what was going on, the rubber hose connecting the waterbox to the engine had come off, starving the engine of fresh air while at idle. Ran fine on the trailer with the seat off.

 

[Gozills]

Finally figured out what was going on, the rubber hose connecting the waterbox to the engine had come off, starving the engine of fresh air while at idle. Ran fine on the trailer with the seat off.

you didnt mention hot water in your hull

 

[RadioWaves]

There wasn't any, don't think it ran long enough to leave a noticable amount of water

 

[Gozills]

Thankfully an easy fix with no collateral damage-good for you!!!