96 GTX carb rebuild

[sschnei]

Appreciate the feedback recieved from this forum...thank you.

So I've gone trhough the '95 and "96 GTX purchased recently. Replaced the gas lines, oil lines, pump oil, and spark plugs on both. Installed fresh batteries and compression check out good at 155 psi. The '95 is done and ready to go.

The '96 got a new wear ring, but still needs carbs work...it's bogging. Could just be the internal filters, but I went ahead and purchased a couple of Mikuni kits. I'm a little reluctant. My concern is getting the carbs set right afterwards...getting the mixture set right so I don't create bigger problems. Are they hard to set and get the mixture right?

Appreciate any input you may have.

Thanks

 

[Minnetonka4me]

Just set it to factory specs and your good to go. I would buy needles and seats too.

 

[Dr Honda]

yep... what he said.

It's not a big deal if you have OEM Mikuni kits. (aftermarket kits suck)

Start the rebuild, and ask questions if you need to know something. We will be here.

 

[sschnei]

Thanks, will do.

Do I need a pop-off tester? Wondering if I should rig up something using my air compressor?

The needles and seats are not in the kit I purchased. Is this a must?

 

[IDoSeaDoo]

I thought I was getting a Mikuni kit, but turns out it was some aftermarket. Since the springs weren't Mikuni, I didn't trust the color as an identifier. I made my own pop-off tester using an aircompressor regulator, a 3 way tee, an old tire gauge,a valve (i used a hand valve for comfort, but a ball valve is an option too), some fuel hose, and assorted fittings to make it all work. It's good to know what your actual pop-off pressure is. I can send you a picture of this if you want.

As for the Needle/Seat, I'd get it, I've had a ski not run at all because the needle would stick in the seat. A sticky needle can cause a severe lean condition and damage the motor, or make it not run at all. When you get the new ones, you'll also see how much easier the needle moves in and out as compared with the old ones. A worn needle can also cause hesitation as it increases the pop-off pressure s it drags across the rough walls of an old seat chamber.

 

[sschnei]

I have the kits in hand and they are definitely Mikuni.

A picture of you pop-off tester would be great. I have some ideas of what I might do based on materials I have in the garage.

 

[IDoSeaDoo]

I tried to attach a crude image I made in paint, but it only accepts URL's. If you send me a PM with your email, I'll send it via email, and if you still want, I can send you a pic of the actual thing when I get home and snap it w/ my cam.

 

[Dr Honda]

in my shop... I just hook a hose from a regulator. (they normally have a gauge) start at zero, and slowly turn up the air. at home I have a cheap hand held tire pump with a gauge.

Yes... you need to verify that your pop-off is right.

 

[sschnei]

Started carb work...removed cables and hoses etc. Ran into problem with one of the top carrb mounting bolts. The head stripped with I tried to remove with T-40 Torx tip. What a start!!! Suggestions on best method to remove???

I have a couple ideas...cut a slot and try to remove w/ screw driver and adjustable wrench or drill the head off, remove carb, remove stud with vice grips. Suppose I could apply a llittle heat to stud if needed.

Suggestions...

 

[Dr Honda]

Last I checked... they weren't Torx bolts. They should be hex.

If the head is stripped, and you can get it out... just get a drill and drill the head off the bolt. (put paper towels in the cabs to keep the metal chips out)

Once the head is off... you can remove the carbs, and you will have a nice big shaft to grab with vice grips. I would heat it, and let it cool first. That will crack the corrosion in the threads. Once again... put some paper towels down the manifold to keep junk out.

 

[IDoSeaDoo]

Honestly, if I were you, I'd remove the whole rotary valve cover with the carburetor. Working on it in the open will be 1000x easier and safer than inside the hull. Also, you won't be heating something that is right next to a gas tank and a bunch of fuel lines. If you do decide to proceed with heating it in-hull, please be aware of the nearest fire extinguisher. The rotary valve cover is secured with four bolts which are the same hex size as the carb bolts. I'm just not sure if you can get to them all with the carb in the way... it's worth a shot. When removing the RV, be sure to mark with a black marker the alignment of the actual rotary valve (big circular flat piece of stainless steel with a hear in the middle) to the black gear in the middle of it. If you accidentally dislodge it, it's kind of a pain to re-align it. Always be careful to not get junk into your engine too

For reassembly: if you haven't already done so, invest in an M8 x 1.25 (i'm 99% sure that's the thread size) thread tap kit, and a brass brush to clean the holes and threads before putting bolts back in. You'll avoid this type of mess in the future. Also, be sure to apply loctite, as bolts may vibrate free.

 

[sschnei]

Great reply...safety first...always!!! Due to space constraints, a right angle drill was required to drill thru the head of the bolt. With the head off, the real culprit was aluminum oxides where the bolt passes thru the body of the carb. Lots of penetrating oil, time and patience was needed to wrestle off the carb. With the carb out the remainer of bolt came off with relative ease.

Now to the carb...both filters were clogged up pretty good...probably from the old gray fuel lines which have already replaced. I think that explains the bogging issue. Filters got replaced with new ones that came in the kits, but I didn't didn't see the gasket and clear diaphram on the pump cover, only the round o-ring was pressent. I don't think this is correct...can someone clarify for me what should be there.

Thank you

 

[Dr Honda]

Filters got replaced with new ones that came in the kits, but I didn't didn't see the gasket and clear diaphram on the pump cover, only the round o-ring was pressent. I don't think this is correct...can someone clarify for me what should be there.

Thank you

Depends on the kit. Some have pump parts, and some don't. Can you lay out the parts, and post a pic?

 

[sschnei]

Attached is the illustration from a Seadoo service manual I downloaded online.

Two items circled in red were not on the carb I disassembled. Seems to me these should be there. If I understand the function of the pump, the diaphram seperates the pulse from the fuel. Without it fuel would be drawn into the engine thru the pulse line.

I believe these parts should be installed these....appreciate your guidance.

Steve

 

[sschnei]

OK, I guess my eyes aren't as good as they used to be. The items I thought were missing were there, I don't know how I didn't see them. Thanks to those we helped me thru this. So...I replaced the oil injector lines since it's easy access with the carbs off. With new lines and filters etc...I got everything back together and headed out to the nearest body of water. Primed the oil injector lines with the skis on trailer backed into the water. Then heade out for a breif lake test... Success :thumbsup: '95 started and ran flawlylessly with good acceleration across the RPM range, no bogging or hesitation what so ever. Put it back on the trailer and did the same with the '96. It started and idled good. Headed out and it seemed to be a little sluggish at first, but squeeze the lever and she takes off like a bat out of h3ll. RPMs zip up to just shy of 7k and with speed topping out about 50 mph. I guess that's about right, I think I read somewhere top speed is around 50-52 mph. Is that right?

 

[Dr Honda]

Good for you. See... wasn't as hard as you thought. (sorry I missed the pump question)


Yes.... the speed, and RPM's seem right to me.

Have fun riding.