1997 GTX carb rebuild- 787

[Rabid]

I started the rebuild on the 97 GTX and as I was dismantling the carbs the low was 0 turns and the high was about 1/2 turn. I know this sounds crazy but I verified which screw I was pulling out. Unless someone had the screws switched. I could not turn in the low t-head and I could the high.
The ski ran fine before I started getting the hesitation which lead me to park it last year.

What I wanted to know was that the ski has a 1.5 n/s & 80g spring (black) does this sound OK or should it have a 2.0

The manual doesn't specify an exact n/s

Thanks

 

[Rabid]

The jets are 142.5 and 70

 

[etemplet]

I just did my 96 GTX and that was not the settings on my carbs. I think I did 1 turn out on the low speed and 1/2 turn out on the high at the PTO, Zero on the high at the mag. I'm having other issues now but when I got the ski both high and low were at zero on both carbs.

 

[racerxxx]

Yes 1.5 and the black spring

 

[Mekanix]

Looks good.

1.5 NS,
142.5 main
70 pilot
Black 80g spring.
popoff 23-32 psi ( most likely to get in that range instead of the 38 it should be)
High speed mag closed, PTO cracked open a bit.
Low speed 1 Turn + - 1/8 turn

Set idle for 1500 in water, tune ls for smoothest idle. Adjust idle back to 1500 or smoothest idle around that.

 

[dieselndoo]

Turn pto hs to 1/2...

 

[Rabid]

What are the tricks for tuning the dual carb system? If you get one too far off, how do you know if you are over compensating on the other?

What is interesting is how the screw set up is different on the two carbs.
I know you need to have a full tank of gas and tune it in the water.

Is there a video someone has on it ?

 

[mikidymac]

The carb settings should be the same as you don't tune them separately. With the exception of only a few years having the HS screw a little richer on the PTO carb as said previously.

A stock seadoo should run perfectly on stock carb settings if everything is correct.

 

[Mekanix]

There is one more thing. Synchronization between carbs. There is enough slop in the carb bolts that you might be way off when bolting them down.

Turn idle screw to off. Make sure mag carb and pto carb are closed completely. If not adjust link rod.

 

[Rabid]

I remember tool that JC Whitney had that was a flow meter for tuning. I guess the air box doesn't allow for that kind of tuning.

Good point about the carb synchronization... Never thought of that. This ski does not have a plate to hold the carbs together like the 99gsxl did.

I did read in another post about those plates should be loose before tightening down the carbs.

 

[Mekanix]

Yeah A manometer would be way too bouncy for this application I believe.

The way I've done it is to turn the idle off and slacken the throttle cable. Then remove the rod and loosen up the jam nuts so it can be adjusted easily.

Then install the link and turn it so that the mag carb isn't pulling on the pto carb's throttle plate.

Then turn the link until you feel very slight resistance and try to turn the jam nuts down until they hold the link from moving.

Try opening the throttle to any point you can compare the two and make sure they are even.

I like using full off and making sure they both move at the same time when going from fully closed to slight crack open.
Usually the mag side moves first and the pto follows which means you need to make an adjustment.
Then compare at full throttle as well.


This is mostly applicable to 96 carbs as 97+ have the accelerator pump style carbs which usually include plastic guides pressed into the carb to reduce the slack and possible error.
I have both types and I find they both need adjustment but the 96 is much more off than the 97+.

 

[mikidymac]

If you do enough of them you can actually hear which one is closing first when you back the idle screw out and let them snap closed.

 

[Mekanix]

If you do enough of them you can actually hear which one is closing first when you back the idle screw out and let them snap closed.

Yeah! that's true

 

[Rabid]

Hello guys

I got the fuel system all cleaned up. I replaced all the fuel lines, cleaned the selector and took a ball of duck tape on the end of a stick and picked up the loose crap on the bottom of the tank.

I mounted the carbs and put the cables on. I checked the Synchronization by backing off the idle screw.

The question I now have is that the throttle cable was stretched out and had a bunch of play in it >1/8 in. I adjusted the cable quite a bit to get the slack out. The oil pump mark was off. Do I line that oil pump mark up with the static setting or do I readjust the mark with the cable set with idle speed added? I have the idle speed backed off right now.

 

[mikidymac]

With the idle set you want about 2mm of free play at the throttle lever so you know it isn't holding the throttle butterfly open. This is when you align the oil pump marks too, after the idle is set.

I would also suggest replacing the fuel selector. I have never seen one that was "cleaned" that didn't start sucking air. The rubber in them is 20 years old and like anything deteriorates.

 

[Rabid]

I was having a hard time trying to figure out what to do from the manual. It stated to open the throttle up all the way then adjust the cable. I could not find where it said to have some play in the cable..I knowvi have tread it in there.

 

[racerxxx]

I never disconnect the cables from the bracket, just the cables from the carbs and then the bracket from the carbs. LOL, I haven't adjusted a cable barrel in like forever. Simplify guys!

 

[Rabid]

Where did that salty dog come from...that interior looks great!!

I got it figured out but how do you adjust the carbs with that airbox on the 97gtx. It totally encapsulates the carb.

 

[mikidymac]

Where did that salty dog come from...that interior looks great!!

I got it figured out but how do you adjust the carbs with that airbox on the 97gtx. It totally encapsulates the carb.

The only thing you should have to adjust is the idle. As I have mentioned before if everything is correct a stock seadoo should run perfect with the adjustment specs from the book. The idle is fairly easy to reach even with the airbox installed.

 

[Rabid]

I followed your directions and it worked out great. I hooked up a boat prime bulb to the return line out of the carb to suck fuel through the carbs for an initial prime. I preset all the cables as if it was the condition I was going to run at. I then loosened the throttle cable a bit and gave the idle couple of turns. The oil pump was set to mark so I would have lubrication. I fired it up with the hose and the idle was at 2700 and the oil pump was sightly ahead of the mark. I will increase the idle and reset the oil pump when the storm passes here. My initial fire up was so I could prime the new oil lines.

I will get the selector switch changed out, replace fuel float and order a poppy cover for the 99 gsx

 

[mikidymac]

Get that primer bulb out of the fuel system. It has no business there and will only cause you problems.

 

[Mekanix]

Was the primer bulb just put in to get the fuel moving? Or were you thinking of leaving it there ?
Im with mikidymac, shouldnt be there.

But to get the fuel moving just to the carbs, that's a good idea. I use a brake bleed pump to suck fuel up to there.

 

[mikidymac]

The easiest way I have found is to leave the return line off the Wye fitting at the carbs. Hold your thumb over the return line and blow air into the vent check valve for the tank by mouth. I know, I know the blow jokes. The air pressure in the tank will force fuel into the carbs and as soon as you see fuel coming out of the carb side of the Wye fitting put the return line back on it and tighten the clamp. Now your fuel lines and carbs are primed and ready to fire with no tools needed.

 

[Rabid]

I just disconnected the return line and used the bulb just for priming then removed and connected the hose and fired it up.

 

[mikidymac]

I just disconnected the return line and used the bulb just for priming then removed and connected the hose and fired it up.

Nice work:thumbsup:. I was worried you were leaving the primer in the line.