1997 GTX flooding and fouling plugs after semi overhaul and carb rebuild.

[robc]

Please help... SeaDoo newbie....my first ski.... That I turned into project seadoo.

I scored a rough running 97 gtx with 132 hours in great condition, trailer and seadoo cover for $500.

Found this awesome forum, read up up on all the common issues with this ski and did some key thing before I started it up after it was sitting for 2 years. I'm a newbie to skis but my 2 stoke and gasoline engine, mechanical knowledge is on point.

--In order I did this---
Cleaned rave valves
Flushed out fuel tank
Replaced all original grey fuel lines
Changed fuel filter
Cleaned fuel selector
Changed jet pump oil
Drained counterbalance oil
Filled counterbalance oil
Changed and flushed out oil tank
Changed all oil lines
Bled oil pump and system
Changed cooling hoses
Changed bilge hoses
Trimmed plug wire ends
Put in new plugs

I cleaned out and rebuilt carbs.....
Used original jets
New 1.5 needle and seats
Checked pop off..ok
--Adjusters--
High speed- set at 0
Low speed- set at 1 turn

New battery
Added gas
Added quicksilver synthetic

Quick shot of starting fluid through the flame arrestor.
Ski fired right up and set idle to 1400 rpm in the water.
(Air box off with flame arrestor in place)

Now my issue is this......
Ski starts cold and idles a bit rough.
Jumps out of the hole.
Topped out at 57 mph....my adrenaline was pumping

When I shut down the ski it will not start unless it sits about 10 minutes or so.
Pulled plugs and they are soaked with gas.
Waited 5 minutes... Put in fresh plugs and fired right up.
Took out out for a 10 minute run, shut it down and same thing....plugs fouled and soaked with gas and had to wait 10 minutes before it would fire up again.

Please help, any help would be appreciated.

Thanks,
Rob

 

[- BiRkS_]

Sounds like leaky needles and seats in the carbs, take it for a run and just before you shut it off, turn the fuel selector to "OFF" then wait 5 mins. try to start it up. then turn on selector. if it fires up, its leaky needles and seats.

As for the idle, try turning low speed out 1/8-1/4turn on each carb.

 

[Sportster-2001-951C-Stock]

"Quick shot of starting fluid through the flame arrestor."

Ether is BIG NO-NO IMO, because no oil lube. And, I've seen ether blow heads off an engine, way too harsh. Use pre-mix instead!

New fuel lines?

Flooding:
Tank could be pressurizing and overcoming carb metering valve(s), check tank vent check valves (should pop around 3psi or less)
Otherwise, your metering valve needle isn't sealing.

 

[robc]

Going to check all suggestions today. As far as the pop off... I was told 25 lbs... so that's what I set them at. Is this accurate?

 

[Sportster-2001-951C-Stock]

Going to check all suggestions today. As far as the pop off... I was told 25 lbs... so that's what I set them at. Is this accurate?

It depends on your airbox, mostly(pop value). If it's a factory setup then keep the recommended pop as spec'd in the service manual, they set them differently from year to year and model to model based on the particular configuration and any changes, such as removing the box to install a FULL RACE sock that gets maybe another 50RPM on the top end will most likely require a total recalibration of the carb(s).

But, if it's actually popping at 25psi, then that wouldn't cause fuel to run/dribble out of the carb bore venturies and into your intake, run down and fill the crankcase with fuel while the engine isn't running. A leaking metering valve would though, possibly even at idle it would be pig rich.

If your fuel tank had lots of internal vapor pressure, it could pop the metering needle and do the same thing, force fuel through the metering chamber into the intake manifold and flood the engine with excess fuel. Relieve the tank pressure by making sure the vent check valves are working properly, and/or burp the excess pressure off by unscrewing the fuel cap briefly. Usually can't resolve a problem without invoking a structured, logical process of elimination of some sort.

So, it's important to differentiate between if the engine is flooding out or if it's not getting (enough) fuel, when troubleshooting a hard restart issue. Wet plugs (from fuel) points to too much fuel and fuel leaking past the metering valve into the intake manifold (for whatever reason).

 

[Strizzo]

25 psi is near the bottom of the range for pop off on the 787, so it may be a bit rich off idle. You could also have a leaky o ring on the seat. Did you use mikuni needles and seats?

As a test, after you put the covers back on with the diaphragms you want to check that the needle and seat will hold 10psi for 30 seconds to be sure it can hold back the fuel system pressure When you shut off the engine.

 

[robc]

Guys i really appreciate your input and help.

Well, yesterday I pulled the plugs and turned it over briefly with the plugs out. Gas blew everywhere, I put my counterbalance oil syringe down in and sucked out as much as I could on both cylinders. I then pulled the carbs again so there was no possibility more gas could get in. I then tilted the ski up as high as possible and removed the counterbalance fill and drain screws as a precaution.....holy smokes.... Lots of gas and oil flowed out. I left it tilted for about 30 minutes to drain. I then reinstalled the drain screw, refilled counterbalance oil and reinstalled the fill screw. I turned it over briefly to try to flush out any excess gas in the bottom of the engine. I repeated that process 4 times to be sure I got out as much gas as possible and as another precautionary measure.

Sportster.... Air box is factory. Apparently the one thing I didn't do when I did all the lines was check the fuel tank check valve. I took it off and couldn't get it to pop for the life of me. I then soaked it in gas and blew it out, it had some of the green sludge that the carbs originally had from the old fuel lines. Once I cleaned it out and now releases upon pressure. Is there anything else that may cause the metering valve to leak?

Strizzo.... Since I had the carbs off I brought pop off up to 29 lbs. Pressure does holds when the diaphragm covers are put back on.

Thanks again guys,
Rob

 

[robc]

Sorry... forgot to ask.... Is there anything else I should do before i put it all back together and fire it up? Maybe with the cylinders or to get any more excess gas that may be in the engine somewhere.

Thanks again,
Rob