98 GTX Limited idle and full throttle problems

[o07mrt]

Hello everyone. I am new here and I have a few questions about my 1998 Seadoo GTX Limited I just purchased. I got it from a friend and before I got it, he had rebuilt the carbs, replaced all the fuel lines, and spark plugs. The problem I’m having with it is, it doesn’t seem to want to stay running when it’s idling. I have to give it a little throttle to keep it running. Around 1500 rpms. Idles at about 800-1000. Another problem is, I get it wide open and it hits about 58 mph and then dies down to anywhere from 38-45 mph when at full throttle. Other then that I love her and she runs great. I appreciate the help everyone.

Also, I believe it has VTS and I don’t see any buttons to trim it.

 

[Coastiejoe]

Turn the fuel selector to RESERVE and see if it improves.
The grey fuel lines the PO replaced plugs the selector pretty often. If it improves replace the selector.

 

[eddie708]

idle is low, should be around 1500 in water and 3000 out of water

 

[Mike99]

The GTX does not have VTS.

Mike

 

[LouDoo]

Most if not all 2-stroke GTX's have a reverse gate, generally ski's with a reverse gate don't have VTS's.

Lou

 

[SabrToothSqrl]

Generally, however the RX is the exception.

 

[o07mrt]

Turn the fuel selector to RESERVE and see if it improves.
The grey fuel lines the PO replaced plugs the selector pretty often. If it improves replace the selector.

Ok so I just took it out and put it on reserve and it completely died. I guess I should replace the selector then. How to I turn the idle up?

 

[Mike99]

Well, you don't adjust the idle until you fix your fuel delivery problem. If the selector is clogged, your fuel lines are gumming up. Replace all of the grey fuel lines, and clean the carbs out (it has internal filters). Running the ski in it's current condition is a sure way to ruin it.

After you have done this, the idle is set at carb. You can download a service manual from this site.

Mike

 

[Mike99]

Oh, re-reading your original post, I see you have new fuel lines. Change out or clean the selector switch. I'd still check the internal carb filters, but that's just me. If you choose not to, and you find any sort of hesitation, or acceleration issues, don't ride the ski until your clean out the carbs again.

Mike

Edited a autocorrect issue...

 

[Coastiejoe]

If the selector was/is gummed up. The issue could be from the selector to the carbs. I would also pull the internal filters and make sure they are in fact clean.

I'm betting there is goo in the needle and seats or the jets as few REALLY know how rondo the carbs properly.

If it were me, I'd replace the selector and send the carbs to [MENTION=16022]Dr Honda[/MENTION].

 

[o07mrt]

Update here. I proceed to take off the selector valve and noticed that the hose for the reserve side to the fuel baffle is the old grey line and was completely clogged. Probably explains why it shut off when I switch it to reserve. Now nothing was in the removable fuel filter in the front. After I replace that one line, should I rebuild the carbs again?? I did get a new selector valve but it was the wrong one that takes 6mm hose instead of the 8mm. Don't know if I can do a reducer or if that will starve it of fuel. Thanks a lot everyone.

 

[Coastiejoe]

At the very least remove the internal carb filters. If you still have an issue then yes, rebuild again.

The green goo from the Grey Lines can be a nightmare.

 

[o07mrt]

At the very least remove the internal carb filters. If you still have an issue then yes, rebuild again.

The green goo from the Grey Lines can be a nightmare.

Is there a way to to remove the carb filters without pulling the exhaust off or do I have to pull that pipe off?

 

[AdamXP800]

The goo can be terrible


Sent from my iPhone using Tapatalk

 

[Coastiejoe]

Is there a way to to remove the carb filters without pulling the exhaust off or do I have to pull that pipe off?

I can't answer that question. I have not done the job myself as of yet.

 

[Dr Honda]

The carbs need to come off, and be cleaned and checked. What you are describing can be from clogged lines, clogged filter, or a leaking/clogged valve. BUT... the pop-off could also be excessively high.

I'm not sure how well your buddy knows Mikuni carbs... but there are a few things to watch for, and are mandatory to be checked. a few of witch are the needle/seat size, and the pop-off pressure. I can't tell you how many carbs I've seen with the TOTALLY wrong spring in them, and the owner would say... "I just used the spring in the kit".


And finally... DO NOT CONTINUE TO RUN THE SKI !!!!!!!! With the RPM's dropping like that... you are going lean, and that is a sure death to a 2-stroke. (No fuel+ High RPM = Heat, and no lube)

 

[o07mrt]

The carbs need to come off, and be cleaned and checked. What you are describing can be from clogged lines, clogged filter, or a leaking/clogged valve. BUT... the pop-off could also be excessively high.

I'm not sure how well your buddy knows Mikuni carbs... but there are a few things to watch for, and are mandatory to be checked. a few of witch are the needle/seat size, and the pop-off pressure. I can't tell you how many carbs I've seen with the TOTALLY wrong spring in them, and the owner would say... "I just used the spring in the kit".


And finally... DO NOT CONTINUE TO RUN THE SKI !!!!!!!! With the RPM's dropping like that... you are going lean, and that is a sure death to a 2-stroke. (No fuel+ High RPM = Heat, and no lube)

Thanks you a lot guys. Its getting a little cold around me finally so it will give something to do. Dr. Honda, is there a step by step on how to rebuild these Mikuni carbs???

 

[LouDoo]

Yes there is:

Step 1: Remove carbs.

Step 2: Drain gas from carbs.

Step 3: Place carbs. in a box with appropriate packing materials.

Step 4: UPS carbs. to Dr Honda.

The carbs. will be done right for no more than you can do them yourself, probably less.

Lou

 

[SabrToothSqrl]

I don't both rebuilding 20 year old carbs. they are like $400 new on the internet, then you can sell your old ones for $100.

for $300 you get brand new, working, not 20 year old carbs.

I'm sure Doc is great, and I've heard only good things, but the fact is, these parts are 16 years old! for the time and hassle for me to take them off and back on/ etc. I'd rather just bolt on new...

 

[midway]

Thanks you a lot guys. Its getting a little cold around me finally so it will give something to do. Dr. Honda, is there a step by step on how to rebuild these Mikuni carbs???

What Lou said. I rebuilt mine, for the time and trouble, the Dr is the way to go. Even though I know how now, should I ever need to do it again, Dr Honda will do it for me.

 

[Coastiejoe]

Yes there is:

Step 1: Remove carbs.

Step 2: Drain gas from carbs.

Step 3: Place carbs. in a box with appropriate packing materials.

Step 4: UPS carbs. to Dr Honda.

The carbs. will be done right for no more than you can do them yourself, probably less.

Lou

Thats funny, but mostly because that is EXACTLY what I was going to do..