97 seadoo gsx cranks but won’t start

[Fernando rides]

So I just rebuilt the engine on a project 97 seadoo gsx and the problem is it will crank over with spark just fine, but won’t start. I know the motor has good compression because it was just rebuilt and the battery and plugs are new too so the spark is good. I put new fuel lines in and rebuilt the carbs so I really don’t know what to do next.

I’ve rebuilt many other of my toys but I’m new to seadoos so any help and tips or tricks to get it running would be very much appreciated

Thanks in advance!!

 

[GGuillot]

So I just rebuilt the engine on a project 97 seadoo gsx and the problem is it will crank over with spark just fine, but won’t start. I know the motor has good compression because it was just rebuilt and the battery and plugs are new too so the spark is good. I put new fuel lines in and rebuilt the carbs so I really don’t know what to do next.

I’ve rebuilt many other of my toys but I’m new to seadoos so any help and tips or tricks to get it running would be very much appreciated

Thanks in advance!!

Sounds like you may not be getting fuel to the carbs, you may need to prime it a little. Take the return line off the back of the carbs that feeds back up to the tank and blow in it. Keep blowing until you get fuel to the carbs. I replaced my fuel lines with clear tygon, so I was able to visually see it moving along. You may need to disconnect at the inlet on the front of the carbs to verify if you used non clear lines.

Fully charged battery, hold the choke open, hit it for about 10 seconds at a time, within the third try or so it should start right up. Then start setting the idle and so forth, make sure it's fairly stable running before turning on the hose. Then make sure hose off first, blip the throttle a few times then load up and go get on the water..

Should be running a premix in that first tank or two for break in. I like to stay at about half throttle for the first few hours and no WOT on the first tank. Second tank of premix a little bit of brief WOT, then after that tank regular fill up using marine stabil every time adding fuel.

 

[Fernando rides]

Thanks, I’ll definitely try that but just to clarify when you said blow into the return line which way should I do that?? As in blowing towards the carbs or towards the tank? I have about 5 gallons premix in the tank right now and I’ll add some more when I go to ride and I think fuel flowing through the carbs might be the problem because they have been sitting bone dry for that last couple of months and I put new clear lines on too.
So I guess my next question is, is this all I have to do to prime the fuel system or should I do other things to get fuel flowing to the carbs?

I’m definitely new to this so I really do appreciate the help

 

[JJinSC]

The procedure described would have to be toward the tank.

Did you replace the fuel selector valve. It may be bad keeping you from getting fuel.

I know you said you replaced battery and plugs but did you test for spark?

 

[GGuillot]

Thanks, I’ll definitely try that but just to clarify when you said blow into the return line which way should I do that?? As in blowing towards the carbs or towards the tank? I have about 5 gallons premix in the tank right now and I’ll add some more when I go to ride and I think fuel flowing through the carbs might be the problem because they have been sitting bone dry for that last couple of months and I put new clear lines on too.
So I guess my next question is, is this all I have to do to prime the fuel system or should I do other things to get fuel flowing to the carbs?

I’m definitely new to this so I really do appreciate the help

My experience from starting with a bone dry tank you need at least 10 gallons in it to get it moving to the carbs. Yeah, towards the tank, just disconnect from the back of the PTO carb where they Y together. Since you have clear lines just watch it start moving to the fuel selector then to the strainer then to the carbs.

Wouldn't hurt to have replaced the selector and the oring in the fuel strainer.

 

[Fernando rides]

Yeah I definitely have spark in both plugs and I haven’t gotten a chance to try anything yet but I’ll for sure check the selector valve and get the fuel flowing through tomorrow.

Hopefully that will do the trick but either way I’ll keep you guys updated... thanks

 

[Fernando rides]

Ok so here’s the update...
I disconnected the the return line at the Y and blew through it, after a little bit I could definitely see that fuel was flowing into the carbs so I know the selector valve is good and that I’m getting gas to the carbs. After I went to try and start it and I got one good backfire out of the carbs (the screen/filter thing was still on) and then it just kept on turning over and nothing else I gave it about 5 good try’s of about 10 seconds each before my battery ran out of juice, but nothing.

I’m not sure if it is something that could happen but is there any way that the ignition timing could somehow be off or is there something else? I know that spark is there and fuel is getting to the carbs just fine so if the ignition timing isn’t the problem then are there any other things that could be off or need to be adjusted?

 

[Ckrawiec]

When you rebuilt the carbs...did you use genuine MIKUNI carb kits or aftermarket kits. The AM kits are notorious for causing all sorts of non-start issues even if you can confirm that you have fuel and spark to the cylinders.

 

[GGuillot]

Ok so here’s the update...
I disconnected the the return line at the Y and blew through it, after a little bit I could definitely see that fuel was flowing into the carbs so I know the selector valve is good and that I’m getting gas to the carbs. After I went to try and start it and I got one good backfire out of the carbs (the screen/filter thing was still on) and then it just kept on turning over and nothing else I gave it about 5 good try’s of about 10 seconds each before my battery ran out of juice, but nothing.

I’m not sure if it is something that could happen but is there any way that the ignition timing could somehow be off or is there something else? I know that spark is there and fuel is getting to the carbs just fine so if the ignition timing isn’t the problem then are there any other things that could be off or need to be adjusted?

When the engine was rebuilt was all the top dead centering and verfying RV timing done? with a degree wheel? How about the mag cup? magnet for the pickup in the right spot? The backfire through the carb is a good indication it's firing, but it may be off.

 

[Fernando rides]

Ok sorry it took me a while to get back here but yes, the rotary timing was done when at top dead center and it is correct. However I believe that my ignition timing is the problem and that it is because I received the engine in parts and the magneto was removed from the starter gear (sorry if this is not the correct terminology) but I thought that I had put it on correctly according to the manual. I had the hole in the gear lined up with the magnet and I thought that was all that had to be done. I believe I am wrong about that and I haven’t been able to find anything on how to install correctly so any help would be greatly appreciated...
Thanks

 

[mikidymac]

It is possible to get the MAG Cup on wrong.

I think @Matt Braley might have had some pictures of the correct position of the MAG Cup on the Flywheel?

 

[Matt Braley]

Sorry I don't have one handy look for ghosting on the flywheel

 

[GGuillot]

I had the hole in the gear lined up with the magnet and I thought that was all that had to be done.

This is correct. magnet adjacent with the hole.

Where do you have the throttle plates at? run the idle screw out until both plates lay flat. With the idle screw just touching, go 2 full turns in. Set the slack on the throttle cable at this point at 3/32" the cable shouldn't be holding the plates open. At this setting, recheck the oil pump alignment marks, with 2 turns in you should only need to tweak a 1/4 turn or so either way on the idle screw, but it'll at least start and stay running.

 

[Fernando rides]

Thanks for the replies guys, I got the magneto back on in the correct spot but just to check, does the orientation of the gear and magneto on the end of the crank shaft matter as long as the magnet is adjacent to the hole? If so how would I go about putting it on? And as for the throttle plates they are in sync and rest fully closed. I’ll finish putting everything back on and adjust the idle screw when I get a chance sometime tomorrow and check the oil too and then we’ll just see what happens

 

[GGuillot]

does the orientation of the gear and magneto on the end of the crank shaft matter as long as the magnet is adjacent to the hole?

It definitely matters, but it should only go on one way, you've got the little woodruff key on the crank that does that orientation for you.

 

[PorknBeans]

This is my picture from my flywheel and mag cup from my ‘96 GSX before I rebuilt it and the arrow shows the hole and the the magnet alignment.

 

[PorknBeans]

This photo shows the “arrow” for the rotation direction and it should be installed with it at the top. The flywheel alignment hole will line up once the magnet is properly placed.

 

[PorknBeans]

Be sure your Woodruff Key is properly installed as well. If it’s damaged. A new one is dirt cheap and required to properly time your engine along with the degree wheel for the 159* rotary valve. Be sure the MAG(front) cylinder is at TDC before timing the valve with the degree wheel.

Here is your shop manual:

http://seadoomanuals.net/download/pdf/service/manuals/1997/1997-seadoo-service-shop-manual.pdf

 

[PorknBeans]

 

[Fernando rides]

Hello again, sorry I haven’t gotten back in a while it’s been a little busy but I’ve done some more testing and made some progress thanks to you guys but here we go...

So last weekend I got everything put back together and long story short after some tweaking and perseverance I got it to run for about ten seconds. First it was really boggy and basically just spitting and coughing out exhaust and then it went from that straight to the rev limiter until I shut it off (for fear of damaging something) after letting it sit for a second I tried restarting and nothing.

Fast forward to earlier today I got out there to work on it for a little and I adjusted both low speed screws to 1 turn out like the manual suggests and got one insane backfire out of the carbs (which I believe was because of the gas valve accidentally not being turned off and extra gas getting in) and nothing after that. So I decided to try 2 turns out on both low speed and got a lot of thick smoke coming out of the exhaust and more backfiring from exhaust (but I can tell you it was getting too much fuel and not going to start). After that I went 3/4 turns out and started cranking it over and it sounded good but as a result of all the misfires in the past the tubing that goes from the water box to the exit cracked/split and was leaking a lot of exhaust into the hull and I called it a night then.

So now to the point even though that wasn’t a very short story. I’m pretty confident that the carb settings are the problem, particularly the low speed for now. So if the 3/4 out won’t get it started and idling when I swap out the tubing from a parts ski, what do you guys with 787’s have your low speed screws at? I’m aware of what the manual recommends but that just isn’t cutting it.

If you made it this far thank you so much for taking the time I really do appreciate it. And also if you think I should post the carb questions on a different thread then that works too I just figured I’d keep this together.

 

[PorknBeans]

I would go through the carbs again. Seems like a fuel delivery issue. Maybe the needle is sticking closed. What is the pop off pressure of the carbs? Pop off tests should be performed with WD-40 at least 3x for an average psi. I’m assuming the motor is all stock and zero mods.

Maybe check the fuel line routing too. The 2 fuel lines at the “Y” connector both go to the top fuel inlets of the carbs. Bottom lines are the Return lines to the fuel tank. Check the two Pulse lines to the crank case.

The manual does call for 1 turn out on the Low Speed screws. But I run a Limited set up on my 787 using BuckShot 44mm carbs. So obviously my settings are different than yours. But maybe start with the carbs and check that pop pressure to see where it’s at and to ensure that it is in fact fully being unseated when fuel pressure builds up underneath the valve to allow fuel to flow into the cylinders for continuous combustion.

 

[mikidymac]

Still your carbs. On a stock ski it will run perfect with the book settings.

If it’s flooding I would be looking at needles and seats.

 

[GGuillot]

First it was really boggy and basically just spitting and coughing out exhaust and then it went from that straight to the rev limiter until I shut it off (for fear of damaging something) after letting it sit for a second I tried restarting and nothing.

It went straight to the rev limiter? without touching the throttle? did you adjust the throttle cable? or you might have a vacuum leak. When you rebuilt the engine what did you use to put the case together? When putting the seals at both ends did you use a little 515/518? pressure ck? new carb base gaskets?

As mentioned above, new oem carb kits w/needle and seats is highly recommended when doing an engine rebuild.

 

[Fernando rides]

So I got out there today for a few minutes and got the new exhaust tube put on and figured I might as well see if it would start for me... it didn’t but it sounded soo close I swear it was gonna but regardless I took a video of it so maybe that will help because describing what’s going on is a little tough.

And to answer the questions the motor’s all stock except it’s bored 1mm over (83mm piston now) I sealed the cases nice and tight with some gasket maker, have a new gasket and o-ring seal in every place needed. I think I when it finally started it was burning off all of the extra oil I used when assembling the engine and then it the carbs were not giving enough fuel at the time. And I didn’t get to check the sealing or pop of pruessure but when I do you are supposed to pump air through the gas inlet on the carbs with some wd-40 on the needle and see at what psi it pops off at, right?


The video was too big to upload here so it’s on YouTube now, it was just my phone so the quality isn’t the best but if you wouldn’t mind taking a look.Thanks!

 

[Fernando rides]

Hey, just wondering if anyone had any input on what they thought about the video I posted. I should be able to get to it tomorrow so hopefully I can figure it out.