how does fuel get to the engine '98 GS

[jst4sho]

I'm not getting any fuel to the engine on my 1998 GS. It will start if I put a little fuel down the carb throat. I can blow air back up through the lines and hear bubbles in the fuel tank.
Carb was overhauled at end of last summer and only on water one time by mechanic after he worked on it. The GS ran fine the other day but died after a WOT run across the lake. I slowed to just an idle and engine suddenly died and would not restart. GS had been running fine up until that time except for a little hesitation on giving it gas. It has the grey hoses but if I can blow through I would think gas can get through.
I can do some trouble shooting but am not a mechanic. Please point me in the right direction before I run out of summer.

 

[JPX]

Try flipping the fuel selector valve from On to Reserve. If that changes things, then it is an easy part change......or you could try to clean it.

 

[jst4sho]

I tried that after reading some posts on the forums but it did not work. If it is low on oil does that shut off the fuel supply? It is not out of oil but it is low.

 

[Nate Surveyor]

well, now I just happen to have one just like that!

first, I assume that you have removed all the gray fuel lines, and done a proper burial for them? (that is 6' deep, and pack the dirt back over the spot, and then pee on it!)

Then, get new black ones. I am an overkill kind of guy, so I replaced the vent lines too. And, I got the 3.99 a foot stuff for EFI cars. That comes to about 100 bucks to replace the fuel line! (gasp!:ack

Fuel path is like this:

Starting at the VENT hose, on the side of the sea doo, there is a check valve, that only allows air to enter. then go in to the T fitting, where the line intersects with a line coming from just in front of the seat, where there is a little rubber plug. These lines have to be open to flow.
Back down to the T, then it goes down into the baffle, and inside the top of the tank.
Now, FUEL enters the bottom of the baffle, and goes through a screen. This is a little plastic screen, that collects GOOP from those gray fuel lines, and saves it for the day that it can shut you down, when you are far away from the boat launch site. Fuel then goes up the baffle, (through the RUN side, which is about 2" up off the bottom of the tank) and goes to the top of baffle, to the fuel select valve, where it intersects the hose from the RESERVE side, DEPENDING on the fuel select valve. (The reserve side comes from about 1/2" off the bottom of the tank, and up to here) Then, the fuel goes to the water trap, which is accessed through the trunk, behind the fire put out device. Otherwise known as a fire extinguisher. The fuel goes through this water trap and screen filter, then back to the engine through the MAIN FUEL FEED LINE. At the engine, it enters the pump, and is pressurized to just the right pressure, to keep the engine fed at any RPM. Then, extra fuel goes back to the tank through a fuel return line, and in the top of the baffle.

INSIDE the carb, in enters from the pump, which is activated by pulses from the crankcase, and goes through the LAST filter. This guy is usually clogged up. There are pics of it all over this forum. JPX posted a good pic of it recently. Gotta clean this little filter all the way.

So, you had a breakdown in the fuel system somewhere?



Nate

 

[jst4sho]

Thank you Nate. Sorry to say that assumption on the hoses is wrong. I only a day or two ago joined and learned of the problem so that is on the to do list. I was going to get new hose today but wanted to try a little fuel down the carb first to be sure it would start. It did but died as soon as spoonful of fuel or two burned up then it died. Gas lines are first replacement of course but is there a chance the fuel pump has died???

 

[JPX]

I'm not aware of interlocks that prevent engine from starting when oil is low.

Verify that the low speed adjustment screw(s) are turned out the correct number of turns. Turn LOW fully closed clockwise and then open counterclockwise 1 and 1/4 turns, HIGH fully closed clockwise (0).

Might need to eyeball the accelerator pump next.

 

[jst4sho]

I've been changing out the grey fuel hoses and cleaning out the select valve. When I first read about the grey lines I took one lose some where but could not see that it was such a big deal. However all the info told me to get that done and I am now a believer. The gunk on the inside of those hoses is horrible. Mostly it collects around the connection points in blobs. The carb was overhauled last summer at a local boat repair shop but will need it again if the thing looks much like the hoses. It was only run for a short time after the overhaule so maybe it is not too bad.
Thanks to all for the help and replies. Nate has been a big help since he has the exact model and I got lost in the mass of fuel lines once.

 

[jst4sho]

Well darn! I just finished all the fuel line work and cleaning the internal fuel filter (terrible) and put it all back together and it still won't run. It will srart with some fuel down the carb but when that is used up the motor dies and will not restart. I did not do a rebuild of the carb but had hoped it would at least run after cleaning that filter. It was totally black with junk and I cleaned and soaked for an hour before my wife got me some "Greased Lightning" cleaner she had in the laundry room. That cleaned the filter in seconds. I did not know it was supposed to be nearly white when clean. I was amazed at how good it cleaned but so disappointed when the ski would not keep running. What now other than the obvious rebuild. The mechanic showed a carb overhaul on his ticket last summer but only five dollars for a couple of sparkplugs was all the parts listed. The rest was labor so he did not overhaul the carb or failed to list the parts. Do it myself once the kit gets here. I need a depression pill

 

[Nate Surveyor]

Not so fast, Leroy!

Are you getting gas to the carb FOR SURE?

I think you should answer this first.

And, I'd do that like this:

Remove the FUEL RETURN HOSE from the top of the fuel baffle, or, like mine, the return line is in 2 pcs, with a connector. Take this apart, and hook a longer fuel line on it, (now you can use a pc of the gray line, as this fuel will be wasted anyway!) to place the end well away from the inside of the Doo. And dump a tablespoon of rich pre-mix down the carb, and see if it is pumping fuel out the return line. (careful of fire!) If it is, THEN you know the trouble is on the carb side of things. IF NOT, there is a problem between the carb and the tank. I'd check this before I took the carb off again.

Just my 2 cents.

Nate

 

[seadoosnipe]

Good work NATE....

Nate is right on track.......I take my return off at the fuel pump assembly body. But either way will work. YOu need to make sure your fuel circuit is charged. It's a loop, where fuel is picked up from the tank, pump through the mag carb in a loop, some fuel to the carbs, unused fuel back to tank........all this has to be checked.............

When you clean out the carbs, did you check on the check valves and did you spray a cleaner, with that lilttle red hose attached through all those liittle internal ports to make sure they were clean. And did you ensure that the lever on the needle valve was set proper, to get fuel into the carb?.....

 

[jst4sho]

Thanks gentlement. I've messed with this thing all week so you know who has dinner plans for this evening. I'll try the test tomorrow. Just so I am clear the !998 GS does not have a fuel pump like my cars, right? I've not found anythng I thought was a fuel pump on any of the diagrams or in the craft. It is some pulse by the engine that makes the fuel flow along with whatever pressure is in the tank. Correct me if that is wrong because I am a novice here. I've got the two piece return line just like Nates so that is an easy break location to try the test. Again thanks folks.
Also Mr. Nate the pressure valve by the seat was a problem. The grommet came out of the hole and on trying to press it in by itself it slipped out of my pudgy fingers and went flying to never never land. I still have not found it so the grommet on the hull will go in connected to the valve and hose like you did in the PM you sent.
Thanks again and I will post results of the test this weekend. Grandkids are coming on Sunday so I've got to wrap this up.

 

[derek]

yes it HAS a fuel pump!!! it is not driven by a lever or cam or electric motor. it is driven by a pulse from the crankcase. it is the block about half an inch thick on the front carb. the pulse moves the diaphragm, just like a real fuel pump (cause it is). there are 2 one-way valves on the plate right next to the diaphragm, just like a real fuel pump. if i empty the fuel seperator, the pump will fill it in 3 seconds cranking on the starter. make sure the pulse line is not clogged up.

 

[jst4sho]

Thanks you Derek. All my experience is in the automotive area and the technology has long since passed me by as I turned my interests to video and live audio in my 30s, 40s, 50s in our church. I resigned my position as I entered my 60s so the ski is my only recreation until I re-focus. I so appreciate everyone helping to educate me.

 

[derek]

well the ski you have is retro to the stuff you know-except for it being a 2-stroke. start digging into it...nothing in there will scare or confuse you. and no, there is no interlock between the low oil light any any function of the ski. now, when there is no oil at all...the crank and con rods will become welded together. at that point it will shut off the motor.

 

[Nate Surveyor]

Whelll, Hmmm JST4sho, I looked in my hiper-flying-parts-finder, And it says that your part is in the bottom of your Doo, under the engine, and hiding.


Nate

 

[jst4sho]

Whelll, Hmmm Nate, you can write another chapter to your hiper-flying-parts-finder. Upon checking the coordinates entered and using my Star Trek transporter technology in reverse I found the misdirected grommet between the fuel tank and the black rubber support pad in the bottom of the corner where they meet. I can only surmise that I entered the wrong coordinates before engaging the transporter controls. With a combination of elbow grease and axle grease grommet is installed to proper hull location. Now do I dare tackle the other pressure relief valve on the side of the hull. hmmmmmm!!! Thanks for your help and I trudge on.

 

[jst4sho]

I did this check and fuel is coming out of the return line so I am getting fuel to the carb but I suppose just not through it.
What next gentlemen? Does this mean onward to carb overhaul or is there another diagnostic procedure to try. I must say I am happy with the test just done and thank you for suggesting it. As clogged as the filter in the carb proved to be I'm thinking some of that had to get through to other areas but I await your suggestions.

Not so fast, Leroy!
Are you getting gas to the carb FOR SURE?
I think you should answer this first.
Remove the FUEL RETURN HOSE from the top of the fuel baffle, or, like mine, the return line is in 2 pcs, with a connector. Take this apart, and hook a longer fuel line on it, (now you can use a pc of the gray line, as this fuel will be wasted anyway!) to place the end well away from the inside of the Doo. And dump a tablespoon of rich pre-mix down the carb, and see if it is pumping fuel out the return line. (careful of fire!) If it is, THEN you know the trouble is on the carb side of things. IF NOT, there is a problem between the carb and the tank.

 

[seadoosnipe]

Fuel........

If you have fuel squirting out of the return line, that means your fuel circuit is operating. The fuel is supplied to the carbs......

The carbs work on the Venturi effect. It's sucked in to the carbs by vacuum. But, must overcome the spring pressure to open the needle valve. This seems to be where your problem lies. I haven't read through all your post, but if you rebuilt these carbs, then it's possible that your lever and needle valve is not set correctly. IF the lever is to low, you'll not get fuel lto the carb. IF the lever is to hight, then you'll constantly flood it........

 

[jst4sho]

I thought I replied to snipe's last post but don't see it...hope I'm not posting twice. To get to the regulator side of the carb I will need to get it on a bench. Do you have any tips on removing the throttle, choke cables from the carb? Also any tips for re-attaching to carb to avoid something being out of adjustment.
Boat shop (not SeaDoo shop) indicates on ticket only five bucks for parts (two plugs) and that he cleaned carb along with labor charges. I don't know how deep he got into carb but the jetski was only on the water when he lake tested last year and this year for about 30 minutes before it died on me and would not start. Up until it died it ran fine except for a mild hesitation when opening throttle. It also idled fine and was at idle when it died and would not restart.
Thanks...ron

 

[JPX]

There isn't really a lot to the throttle cables. Loosen the set nuts on the bracket. Then draw the inner cable backwards to slack up the carb pivot. The cable just pops off like a bicycle brake cable (nub at the tip).

Choke cable requires a tiny hex key wrench on the blind side of the bronze nuts. Then the whole bar on the cable end slides out.

 

[seadoosnipe]

Sync...

Like JPX says, it's nothing. But if I might add, when you pop off the carb sync bar, just reach in behind it with a screwdriver and pop it off. Do not loosen the jam nuts on the sync bar.....that will cause them to be out of sync.........:cheers:

 

[robin savell lloyd]

You may have a fuel problem but I woud check the compression as it may start when you put fuel in the cylinder but if compresion is not as it should be the fuel may not make its way threw the crankcase and up into the ports and to the cylinder. I can be wrong as I do not have enough experiance with 2 cycles even thow I have repaired over a thousand of them I am still learing about porting and so forth as most of the 2 cycles that I repaired were disposeable small engines. good luck Robin :cheers:

 

[Nate Surveyor]

I don't know if you have done this yet, but you will probably have to take the spark arrestor off, and then the carb. Removing the throttle cable is no problem, as you just manually rotate the throttle on the carb, creating slack in the cable. Then, it just turns and unhooks. The same with the cable to the oil pump. I do that when the carb is already loosened from the doo, and part way up out of it. I can't remember a play by play on that, but if you are sort of handy with your hands, you will get it.

Be sure you re hook the oil cable back up, or without it you will burn up the motor.

Once you get the carb off, you will find that the little filter inside the carb is full of the resin from those old gray lines. Somebody else said some kind of degreaser was handy to clean this little guy.

JPX has posted pics of this little guy elsewhere on the forum. They are handy to view.

You will have to clean this filter, or you will not ride!

Nate

 

[jst4sho]

I've finished the cleaning and rebuild of the carb. Even those little clear round check valves were stuck to the seating area from all the goo with the old lines. I had to go 30 miles to a Sea Doo dealer to get the carb kit but wish I ordered on line. One of those kits came with better screws to hold the pump side cover on and also a gasket between the throttle body and engine intake. I'll reuse what is there as it looks undamaged. I cleaned everything I could find including the accelerator pump. At this point it is all back together with no spare parts so either I lost them or all got put back to the same spot they came from. I'll put it back on the engine either tonight or in the morning depending on what time the Dallas Cowboys exhibition game starts. The only thing that concerns me is the points where locktite is specified.

 

[Nate Surveyor]

Mr Seadoosnipe, this one has only one carb :hurray::hurray:

So, there is less complexity.

I say the compression test is a reasonable thing to have done already.


Nate
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"You know it's bad, when your shrink keeps calling you for advice!"