SeaDoo not starting

[snoopy]

I hate coming to the forum, seems like I always am asking for something, sorry about that...having said that, I have a 98 SeadooSPX...ran great all year (May-June)until today (live in MN). Was on the lake today and it just died while motoring around. Got it started after a few minutes of trying and again she died and I could not get her started again and was towed in. I have another SPX, swapped the plugs with each other, the one that did run, continued to run with the plugs from the machine that did not run and the one that died on the lake, still did not start with the plugs from the machine that did run. I thought I had bad gas, the day before, I had filled it up with gas that I bought in Fall and added Stabil. I have been using my eight 5 gallon containers all year in my skis and 20i, no problems...thought maybe I forgot to add Stabil to one of the eight 5 gallon containers. Sucked out the gas in the SPX, bought new gas today, filled it, still did not start...in fact later in the day, I used the gas that I sucked out of the broken SPX and used it in the one that works -- no issues....anyone with ideas on why it would just die while running? It seems like it can't get gas to fire up, thanks, guys.

[IDBoating]

I have two SeaDoo jetskis of that era (Rotax 787 engines) and have done a fair bit of work on them. I'll try to help.

"Just died"... did it sputter to a stop? Just seize all of a sudden?

What happens when you try to start it now? Any sound at all? A "click" but no engine rotation? Engine turns but no effort to start at all? Coughs and tries to start but won't stay running?

In other words, we need more data. Please be as detailed as possible. Don't be shy, better to give us several paragraphs of info than one sentence.

[snoopy]

I have two SeaDoo jetskis of that era (Rotax 787 engines) and have done a fair bit of work on them. I'll try to help.

"Just died"... did it sputter to a stop? Just seize all of a sudden?

What happens when you try to start it now? Any sound at all? A "click" but no engine rotation? Engine turns but no effort to start at all? Coughs and tries to start but won't stay running?

In other words, we need more data. Please be as detailed as possible. Don't be shy, better to give us several paragraphs of info than one sentence.

thanks for the response, I will explain a bit more

when it died, it was the same as hitting the start/stop button, no sputtering, just shut off. when I try to start her up, she turns over but never fires. I tried to restart her 10-15 times at least and I did hear her backfire once.

Also, as I swapped out the plugs (2 years old BTW), I did spray fogging oil into the empty chamber and tried to start her up, I covered the openings with a rag, no water shot up/out.

If I to guess, maybe a fuel pump went bad? It just sounds like it is not getting any gas to fire the engine. Can a starter go bad and make her shut down while the ski is running?

[TeamAllen]

Have you tried putting some starter spray or a small amount of gas into the carburetor(s) throat? That is a simple way to figure out if it is a fuel delivery issue. The thing to check is to see if you have spark. You should use a simple tool around $10 to do it safely. https://www.amazon.com/ABN--Line-Spa...k+tester&psc=1

Or there is the less safe, but free method. There is a possibility you could ignite fuel vapors and explode the place.
https://www.youtube.com/watch?v=bHIQ663Rkb0

[snoopy]

Have you tried putting some starter spray or a small amount of gas into the carburetor(s) throat? That is a simple way to figure out if it is a fuel delivery issue. The thing to check is to see if you have spark. You should use a simple tool around $10 to do it safely. https://www.amazon.com/ABN--Line-Spa...k+tester&psc=1

Or there is the less safe, but free method. There is a possibility you could ignite fuel vapors and explode the place.
https://www.youtube.com/watch?v=bHIQ663Rkb0

I did the hillbilly test – – and it is totally different than the YouTube video link above. One plug sparked the other did not. But it did not spark very often – – nothing like the video. What was scary is, I did the same hillbilly test in the JetSki that did work – – the sparks were very limited as well – – nothing like that YouTube video where it was constantly sparking. I put the plugs back in the working JetSki and it did start – – the one that doesn't start still does not work.

I also put some starter fluid in. start up is so close it wants to start-- it started momentarily but then immediately kills– – I am thinking now it may be a fuel problem more than an ignition problem

Perhaps a fuel filter or fuel pump – – any ideas from anyone else? Thanks everyone much appreciated

[IDBoating]

OK. Engines need four things to run: Fuel, air, compression, and spark. Let's find out what you do and don't have.

You say the engine will crank but not start. " Can a starter go bad and make her shut down while the ski is running?" No, the fact that you can crank the engine means the starter is working. And a magically dead starter won't stop an engine, it just won't restart it. So, based on your comments, it sounds like the starter electrical system is fine.

When you pull the plugs from the bad engine, are their electrodes moist? This indicates that the fuel+oil mixture is being delivered to the cylinders. If they are bone dry, then you have a fuel delivery problem. An engine that is being cranked but not running on its own should have wet plugs. This will answer the fuel question. If you DON'T have fuel going to the cylinders, get back to me and I'll walk you through some tests to figure out why.

There is a little fuel-water separating filter somewhere in the engine compartment. Usually it's right under the handlebars. It is held in a translucent cylinder with threads at the top, and unscrews downward like a raw water filter in an inboard boat. Jetskis condense a lot of water in their fuel tanks, a problem made MUCH worse if you use ethanol fuel. Once that fuel-water separating filter chamber fills up, the engine can be starved for pure fuel and sputter or die. You need to periodically unscrew that housing, dump out the fuel+water in it, wipe it clean, and screw it back into place. Be careful of the actual filter inside; it's held in place by friction alone when the housing is unscrewed.

There are plenty of other fuel related things you can do, but do the above first and report back.

Let's presume the carbs are getting air. (You could feel for air coming out of the exhaust while the engine is cranking to be certain.)

When the plugs are out, feel for air pressure coming out of the spark plug holes while the engine is cranking. This is a low-tech way of checking for compression. It's unlikely you had a catastrophic ring failure that stopped your engine, but who knows.

Finally, spark. You've run some spark tests. A cheap spark tester would be a great idea. However, it's odd that the engine "just died". That suggests some event happened, not that you have gradual degradation.

Here's a few things about those two-stroke Rotax engines in the ignition department:

* When in doubt, always use new plugs. They're cheap. I know you swapped plugs with the other machine, but it's not the one having problems. I've had lots of weird problems with these engines that have been solved by brand new plugs.

* Confirm the plugs are gapped properly, and that their electrodes are clean. Especially in that little circular groove around the tip. Two-stroke engines run really dirty, and you can get buildup in that area that shorts out the plugs. (You should decarbon these engines at least once per season.)

* The plug caps and wire ends corrode over time. They connect to the plug wires via what is essentially a little screw tip; they literally screw onto the wire ends. Unscrew the caps, cut off 0.25-0.50 inch of the end of the wire (make sure it's a clean, square cut), and then screw the caps back on nice and firm (screwing them on is basically driving a screw tip down the center of the wire, thus making contact with the stranded wire inside). Secure them with a ziptie around the boot where the wire enters the cap. This will eliminate corrosion problems in that area, which is a big deal with these engines.

After doing all of this, NOW reconfirm that you have spark. Be aware that these engines fire both plugs together, every time, even though the cylinders are actually operating 180 degrees out of phase. That extra spark in the "off" cylinder is called the "wasted spark" in this industry. It seems weird but doesn't hurt anything and makes their ignition system simpler. Make certain you have reliable, regular spark in both cylinders.

Waiting to hear back from you!

[snoopy]

OK. Engines need four things to run: Fuel, air, compression, and spark. Let's find out what you do and don't have.

You say the engine will crank but not start. " Can a starter go bad and make her shut down while the ski is running?" No, the fact that you can crank the engine means the starter is working. And a magically dead starter won't stop an engine, it just won't restart it. So, based on your comments, it sounds like the starter electrical system is fine.

agreed

When you pull the plugs from the bad engine, are their electrodes moist? This indicates that the fuel+oil mixture is being delivered to the cylinders. If they are bone dry, then you have a fuel delivery problem. An engine that is being cranked but not running on its own should have wet plugs. This will answer the fuel question. If you DON'T have fuel going to the cylinders, get back to me and I'll walk you through some tests to figure out why.

plugs are wet/moist/oily

There is a little fuel-water separating filter somewhere in the engine compartment. Usually it's right under the handlebars. It is held in a translucent cylinder with threads at the top, and unscrews downward like a raw water filter in an inboard boat. Jetskis condense a lot of water in their fuel tanks, a problem made MUCH worse if you use ethanol fuel. Once that fuel-water separating filter chamber fills up, the engine can be starved for pure fuel and sputter or die. You need to periodically unscrew that housing, dump out the fuel+water in it, wipe it clean, and screw it back into place. Be careful of the actual filter inside; it's held in place by friction alone when the housing is unscrewed.

dumped the fuel/water mixture

There are plenty of other fuel related things you can do, but do the above first and report back.

Let's presume the carbs are getting air. (You could feel for air coming out of the exhaust while the engine is cranking to be certain.)

When the plugs are out, feel for air pressure coming out of the spark plug holes while the engine is cranking. This is a low-tech way of checking for compression. It's unlikely you had a catastrophic ring failure that stopped your engine, but who knows.

air pressure coming is out is as strong as I remember when I winterize, so no issue there, thank goodness

Finally, spark. You've run some spark tests. A cheap spark tester would be a great idea. However, it's odd that the engine "just died". That suggests some event happened, not that you have gradual degradation.



Here's a few things about those two-stroke Rotax engines in the ignition department:

* When in doubt, always use new plugs. They're cheap. I know you swapped plugs with the other machine, but it's not the one having problems. I've had lots of weird problems with these engines that have been solved by brand new plugs.

replaced the plugs with new ones

* Confirm the plugs are gapped properly, and that their electrodes are clean. Especially in that little circular groove around the tip. Two-stroke engines run really dirty, and you can get buildup in that area that shorts out the plugs. (You should decarbon these engines at least once per season.)

* The plug caps and wire ends corrode over time. They connect to the plug wires via what is essentially a little screw tip; they literally screw onto the wire ends. Unscrew the caps, cut off 0.25-0.50 inch of the end of the wire (make sure it's a clean, square cut), and then screw the caps back on nice and firm (screwing them on is basically driving a screw tip down the center of the wire, thus making contact with the stranded wire inside). Secure them with a ziptie around the boot where the wire enters the cap. This will eliminate corrosion problems in that area, which is a big deal with these engines.

last but not least--I did not cut or clean the wires--just hand manipulated them on both ends...she started up-- it seems to me so odd that this was the problem--they are however close to 20 years old--I will look at this if this problem occurs again-- when I winterize I will make new connections, but for now she is running--hopefully tomorrow she starts and etc etc etc...

After doing all of this, NOW reconfirm that you have spark. Be aware that these engines fire both plugs together, every time, even though the cylinders are actually operating 180 degrees out of phase. That extra spark in the "off" cylinder is called the "wasted spark" in this industry. It seems weird but doesn't hurt anything and makes their ignition system simpler. Make certain you have reliable, regular spark in both cylinders.

Waiting to hear back from you!

thanks so much for your help, if she has any other problems, I will continue with this thread

[IDBoating]

Glad you've got it working. However, allow me to URGE YOU TO TRIM THE PLUG WIRES. The fact that you "fixed" it by wiggling them means they could "unfix" themselves by wiggling some more while riding around.

This is not a difficult project. Just unscrew the caps, trim the wires back perhaps a half inch so you have square ends with bright shiny wire visible at the end, and forcefully screw the caps back on. Secure each with a ziptie around the boot where the wire enters. That's it, and you'll be good (and reliable!) for at least a couple of years.

Seriously, take the time and do this. It's worth the piece of mind.

[snoopy]

Glad you've got it working. However, allow me to URGE YOU TO TRIM THE PLUG WIRES. The fact that you "fixed" it by wiggling them means they could "unfix" themselves by wiggling some more while riding around.

This is not a difficult project. Just unscrew the caps, trim the wires back perhaps a half inch so you have square ends with bright shiny wire visible at the end, and forcefully screw the caps back on. Secure each with a ziptie around the boot where the wire enters. That's it, and you'll be good (and reliable!) for at least a couple of years.

Seriously, take the time and do this. It's worth the piece of mind.

I am back – – the damn thing happened again. I was out riding it hard in some heavy waves – caught some big air landed hard and the thing sputtered and died on me and did not start. What had happened, and I'm not sure what you call the box, but it is located next to the battery. There is a wire that just popped off the electrode. I am on my cell phone right now but I will post a picture of what happened later. SHe is running great once again

[IDBoating]

Depending on how your particular machine is laid out internally, that's likely the ignition box. It has the spark plug wires coming out the top, right?

Some of those had a separate wire that ran to the negative battery terminal. Having that wire disconnected definitely kills the engine. Is that the wire you're talking about?

More info, please!

[snoopy]

Depending on how your particular machine is laid out internally, that's likely the ignition box. It has the spark plug wires coming out the top, right?

Some of those had a separate wire that ran to the negative battery terminal. Having that wire disconnected definitely kills the engine. Is that the wire you're talking about?

More info, please!

one of the blue connectors was completely disconnected from the metal tab...put it back on and she fired right up...I figured something was disconnected because I really did land hard and like I said, she sputtered, then died. I figured a loose wire somewhere in the mix, sure enough, opened up the box and saw the problem immediately. Here it is with both of them reconnected

ignition wires.jpg

[IDBoating]

Yep, that's the ignition box. It probably has the ignition coil and starter relay in it. I suggest slightly crimping the contacts in the blue connectors and then reinstalling them so they fit nice and snug.

I also still suggest you trim the spark plug cables. If I understand correctly, fiddling with them fixed things last time. Why not make that permanent?