2 stroke jet ski not working

Rob2593

Good evening

I have a 2 stroke 2001 Yamaha 800r but am currently having an issue with it. Basically I took it out with a friend and it capsized a few times. After that it worked for about 20mins and then it started losing power. I brought everyone back to the harbor where just as I was at the slipway it cut out. I kept trying to start it and it would start for a few seconds then turn off. Now however, it won't start at all. You can hear the motor trying to start it but it won't start properly.

Anyone have any ideas what the problem could be? Or where I could get it looked at in Dublin?

I've made sure there was no water left in the hull (which there was a bit until we got it off the slipway) and also made sure there's none still in the engine.

Help would be much appreciated, I've only had the thing for 2 days!

Pigeon Reaper

Are you getting a spark when the engine is turning over? Water in the electrics might be shorting out your HT leads to the spark plug. Remember you need three things to make the engine run, fuel, air, ignition source.

Rob2593

Basically when I press the start button it makes the normal sound, then when I press the accelerator in slightly (which is necessary to start it) it makes a slightly different sound, which I presume are the spark plugs? The battery and spark plugs are brand new apparently.

Do you think if I let it dry out overnight it might work again?

Thanks for the response by the way, I appreciate it.

Stheno

I'd leave it dry out and then take it to someone if it's still not working.

Totally OT but do jet skis have any sort of kill cord if they capsize/people fall off them?

Genuinely curious

fergal.b

I'm no expert on jet ski's but I believe when they capsize you must roll them counterclockwise or anticlockwise depending on the ski "it will state this in your manual or on the back of the ski" this will stop the water from going up the exhaust to the piston chamber. If you try and start it with water in the chamber you could end up bending the valves. :eek:
The first thing you should have done was take out the spark plug and turn the engine over to see if any water came out also have a look at your fuel and oil tank for any signs of water if you find some drain and refill. If it was salt water and it's been more than a few hours since it happened you might have to get the engine overhauled.


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Rob2593

Stheno wrote: »

I'd leave it dry out and then take it to someone if it's still not working.

Totally OT but do jet skis have any sort of kill cord if they capsize/people fall off them?

Genuinely curious

They do indeed have a kill cord which shuts the engine off once it's removed.

@Fergal I did flip it back counter clockwise each time. I can't get my hands on a spark plug remover until tomorrow evening. Is this a serious problem?

fergal.b

It can be a serious problem if you tried to start it with water in the cylinder it's called hydrolocking and puts a lot of internal pressure on the inner workings of the engine. Take the plugs out and turn it over to get the water out then spray everything with WD40, if you can't get it to turnover with the plugs out the problem might be electric and that could be a good thing if there is such a thing.



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Rob2593

fergal.b wrote: »

It can be a serious problem if you tried to start it with water in the cylinder it's called hydrolocking and puts a lot of internal pressure on the inner workings of the engine. Take the plugs out and turn it over to get the water out then spray everything with WD40, if you can't get it to turnover with the plugs out the problem might be electric and that could be a good thing if there is such a thing.



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I see, by turning it over do you mean take it off the trailer, turn it on its side or upside down? What exactly should I be spraying with WD40? Inside the hole where the plugs go?

Sorry for all the questions, as you can tell I'm new to this whole thing

fergal.b

Sorry what i mean is turn the engine over "try starting it" with the plugs out this should force any water out of the cylinders then spray a bit of WD40 into the cylinder through the plughole this should help prevent it from rusting.



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Rob2593

fergal.b wrote: »

Sorry what i mean is turn the engine over "try starting it" with the plugs out this should force any water out of the cylinders then spray a bit of WD40 into the cylinder through the plughole this should help prevent it from rusting.



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Ahhh I see, okay I'll try that tomorrow once I buy some WD40 and a spark plug remover.

On a side note; what's the best way to secure a jet ski & trailer? I was thinking clamping the wheel but how would I stop someone from just taking the jet ski off?

fergal.b

Rob2593 wrote: »

Ahhh I see, okay I'll try that tomorrow once I buy some WD40 and a spark plug remover.

On a side note; what's the best way to secure a jet ski & trailer? I was thinking clamping the wheel but how would I stop someone from just taking the jet ski off?

You could get a long plastic coated steel cable lock and go through the wheels and up and over the ski or down between the engine and drive shaft and back up, you also have the bow eye that you could lock to the trailer. Cover the ski and trailer with a tarp, put it in a corner or close to a wall and park a car in front of it.




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Rob2593

Okay so I've done the following:-

Took out the spark plugs
Turned over the engine - no water shot out
Sprayed WD40 in the plug holes
Put a towel over the holes and turned over the engine again
Put spark plugs back in and turned over again - no start
Removed spark plugs from hole but left them in HT leads and saw they were sparking.

I'm honestly out of ideas now. Anyone else have any ideas I can try? Right now I have the ski outside with the seat off and the plug holes exposed (trying to let it dry out) in a bit I'll buy new spark plugs and try them.

fergal.b

Did you check the fuel to see if any water got in, you might have to drain the tank and fuel system to be on the safe side. If your plugs are sparking there is no need to buy new ones.



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Rob2593

fergal.b wrote: »

Did you check the fuel to see if any water got in, you might have to drain the tank and fuel system to be on the safe side. If your plugs are sparking there is no need to buy new ones.



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How would I drain the tank though, the fuel tank is under the nose of the craft? I can look through the space where the seat comes off and I can see that there is still fuel in there, probably 3/4 full. How would I see if there is water in there?

I rang up a jet ski repair place in Dublin and they said to put a tablespoon of petrol in the plug hole and try it then so I'll give that a go later today and hope for the best.

fergal.b

Do you have a water separator somewhere along the fuel line ?



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Rob2593

fergal.b wrote: »

Do you have a water separator somewhere along the fuel line ?



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I believe there is, but I've no idea where it is. I've tried looking on line and no where I could find shows where it is located. Do you know where it would typically be located? Also what should I do once I find it?

fergal.b

What make of ski do you have. It could look something like this you unscrew the bowl and see if water is sitting at the bottom.

Rob2593

fergal.b wrote: »

What make of ski do you have. It could look something like this you unscrew the bowl and see if water is sitting at the bottom.

It's a 2001 Yamaha 800R. I took a good look and think I may have found it. It's at the nose and it seems to look somewhat like the picture. Will I just unscrew it and let the water fall out into the hull (as it's too far in to be able to stop that from happening - only space for one arm)

fergal.b

Try and put a clear plastic cup under to see if there is water, If it has a little tap on the bottom of the bowl the water will come out first when you open it if it's like the one in the pic remove the bowl keeping it upright then pour into the cup and wait a while for the fuel and water to separate.

Rob2593

fergal.b wrote: »

Try and put a clear plastic cup under to see if there is water, If it has a little tap on the bottom of the bowl the water will come out first when you open it if it's like the one in the pic remove the bowl keeping it upright then pour into the cup and wait a while for the fuel and water to separate.

Okay I did that and found there was water in the fuel tank. From there we drained the whole thing and put new fuel in. After doing so it still wouldn't start. The air filter is very wet, is this a problem?

We did a compression test and one cylinder was 9 bar whilst the other was only 2.1/2. Does this mean I need to get new piston rings? If so, any idea how much a job like that would cost?

fergal.b

Looks like you have a problem alright 9 bar is about 130 psi about right for this engine 2 1/2 is very low and the engine will have to be overhauled it could be a bent valve so you could also have water in the crankcase. I have no idea how much it will cost as it will depend on the damage thats done.
If it was salt water you might have to cut your losses as it will have started to eat away at everything on the ski by now and you could end up with problem after problem :eek:

A hard lesson learned but at least you got back safe and sound it could have been a different story if it cut out further from land. The water separator is one thing most skiers and some boaters check before hitting the water and should especially have been done after you capsized the first time as you capsized a few times you must be doing something wrong and recommend taking lessons and learning a lot more about jet skies before hitting the water again.





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breghall

The future of the jet ski doesn't look good Rob. Water in the fuel prob caused a lean condition and scored the cylinder which has caused the low compression. A re bore, new pistons, piston rings, gaskets and labour probably 1000 +. Might be cheaper to find a second hand engine.

Pour some two stroke oil into the bad cylinder and see if the compression figure goes up .... the carb(s) would have to be drained of the bad fuel too as well as the tank.

Rob2593

I'm bringing the jet ski to a repair place tomorrow and I'll get them to have a look at it. I rang up a guy who rebuilt the engine before and he reckons it's the cylinder. I've poured oil into the cylinders to slow down the erosion from the salt water until it can be taken apart and looked at.

Just for the record, I only had it flip once whilst I was driving it, which was due to me stopping in the water and a wave hit us sideways. The other two times were when my friend was driving (he's quite large and has poor balance, a mistake I won't be making again).

However you are dead right, it could have been much much worse if it had of cut out where the big waves were. So for that, I am thankful. Also thank you everyone for the advice and info, it has been a huge help.

JamieHarris

Is it a new purchase? If there was water in there it would be separated