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  1. #1

    2000 GTX help with accelerator pumps (I think)

    I have a 2000 GTX original owner, about 100 hours. Did not need to do much maintenance over the years (just the basic stuff) so the engine/carbs were pretty much how it came from the factory. Two summers ago I replaced the fuel lines and cleaned the carb screens. This past summer I kind-of rebuilt the carbs. "kind-of" means I replaced gaskets, diaphrams, screens but did not touch the pop-off spring/assembly. I did not have a tester to check the pressure afterward and did not want to mess with it since it looked in pristine shape (I know that does not mean the spring is okay). The carbs in general looked in great shape - very clean. I tried looking at the accelerator pumps but did not take the hoses off because I did not have clamps that size to replace the current ones. That may sound like a stupid reason but given the odd things I have had happen working on it in the past (i.e., cleaning the carb screens I stripped a screw head for a screw not found in parts finder, by me or the dealer, and had to stack washers on a longer one to fit) I now will not touch anything unless I have as much prepared as possible.

    Now before I rebuilt the carbs I had an issue where going WOT from a dead stop would bog the engine and it would stall. Slowly applying the throttle until it got moving then WOT worked. After rebuilding the carbs it was better, meaning I did not have to slowly apply the throttle as much and for as long, however WOT from a dead stop still caused it to stall.

    Reading other posts it sounds like the accelerator pumps may not be working or clogged, or the low speed screws need adjusted. When I worked on the carbs I tried checking if the accelerator pumps were working but did not have any success. I read a post that said with the intake off the pumps should spray fuel when applying the throttle (even with it off). I did this but nothing sprayed. Not sure if I did this wrong (needed to have it running???) or if the pumps were not working. Any thoughts???

    As for the low speed screws, as mentioned no carb work was done since new so I am not sure why these would need adjusted. Open to looking into it if necessary but not clear on how to do this on the water (i.e., the screws do not seem to be in an easily accessible place to adjust while docked).

    One other thing is I have never touched the Rave valves. I know they control high RPMs but I thought I read if they are stuck open it can affect low rpm performance. They are next on my list to look at. My RPMs are around 6800 (+/- 50 depending on the conditions).

    Open to suggestions on what the problem can be and also how to diagnose (and fix) the accelerator pumps.

    Any help is greatly appreciated.

    Thanks


  2. #2
    These accel pumps can be tricky to fix. You should see a stream of fuel out the nozzles when opening throttle with intake arrestor box off. ( must be full of fuel..)

    Usually the nozzles clog up. Note that if there is an internal issue with the pump, there is no cure as they didnt make a rebuild kit for it. You need to buy a used one and hope for the best.

  3. #3
    This is how I run a jetski shop in the desert nmpeter's Avatar
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    you certainly want to check the raves to make sure they are moving freely. you can run the engine with the caps off. Spec calls for cleaning ever 50 hours.

    if you didn't mess with the float arm. can we assume you did not change the needle seat..or inspect them for that matter?..you could have blockage at the base of the seat.(that's in line AFTER the mini filters)

    _good_ fitting screwdrivers and a vise are a must for carb work. Only the hacks strip screws on carbs..they are pretty high quality and unless the carb is a real mess, my favorite snap-on number two and a couple of light taps with the brass hammer is all I've ever needed to budge screws out of the way. I have an older sears Phillips I use on the smaller internal screws..had it forever..It's in my sack of carb tools which are used only for that bit of work. Got a couple of ground down straight blades for getting the jets out and so on.

    +1 on the accelerator hose lines..they get brittle and leak and the clamps are tricky as they are tiny tiny tiny.

    you should get some spray action with the engine off..if the float chambers are still full.

    A bog when going wot from idle is typically a pop off pressure issue as the carb needs to flow fuel the moment the vacuum on the engine side drops from going WOT

    check your plug gap, it should be spot on, make sure the high speed screw is totally closed (that's factory setting)

    every single carb screws is available, you won't like the price on some of them but I'm sure another member can help out with a screw from some junker carbs if you are pinched for it.

    more details helpful....

  4. #4
    Ken62465's Avatar
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    Jaym24,
    I've dealt with clogged accelerator nozzles and I use a Mity-Vac hand pump for this and for checking pop-off pressure. You can apply a small amount of pressure to blow them out...last nozzle took me 30psi right to the brink on the Mity-Vac to push the crap out and works like a charm still 2years later. Also as a rule whenever I rebuild a carb set I always insist on new needles and seats. They do not come in the rebuild kits as I'm sure you know. That bog could also be the fuel delivery system itself..meaning fuel lines. The 2000 model ya got there had those old grey Tempo fuel lines and they're prone to degrade with a green slime. I cleaned a set of carbs out once this crap was caked all over the fittings and reduced their size by half and it sure caused a nasty hesitation out of the hole. I'd replace the fuel lines, and pull the fuel selector and clean it out good!!

    And I hate those carb screw cause I must be a hacker cause I've stripped a few from some nasty carbs before...easy out! I gave up on the phillips and a flat head does a way better job. I also like to swap out the phillips for allen socket head....way better and SS ones can be had at your local hardware store.

    New Needles and Seats...check pop-off!
    replace fuel lines
    pull and clean out fuel selector.

    Get yourself a Mity-Vac...I even bleed brakes with the thing and it works wonders without a helper pumping the brake peddle.

    If your Rave valves were stuck open it would not bog out of the hole. It would just be a dog until it reached upper 5k or more RPMS. They allow for a degree of backpressure until peak rpms are reached and then backpressure is no longer needed in a 2 stroker. You can pull the caps off and check them easy enough. I've even ridden with the caps off to check them and ya..they're open and a dog out of the hole when you do this but it tells me if they were opening or not. They sit down a bit and you can also see them rise up with the caps off. You can clean those Rave guillotines in minutes.

    Lastly...get yourself familiar with the difference between a bog and a hesitation..different feel. A bog the engine will be rich and gurgle in sound until cleared out. A hesitation feels more like a flat spot of no fuel then it bites and takes off.

  5. #5
    Thanks for the reply.

    Quote Originally Posted by nmpeter View Post
    if you didn't mess with the float arm. can we assume you did not change the needle seat..or inspect them for that matter?..you could have blockage at the base of the seat.(that's in line AFTER the mini filters)
    Did not replace the needle/seat, but looked at as much as I could. They were extremely clean and appeared to look really good, but no idea if that means they are fine.

    Quote Originally Posted by nmpeter View Post
    _good_ fitting screwdrivers and a vise are a must for carb work. Only the hacks strip screws on carbs..they are pretty high quality
    They appeared to be aluminum to me (i.e., soft and easy to strip). This was my first go with carbs on a watercraft and from other research it appeared they could be serviced without taking them completely out of the watercraft. That is what I did the first time and had an issue with just one screw. The second time I removed them completely which actually was not nearly as bad as I thought it would be - should have done that the first time (was mainly worried about throttle cable and oil cable settings, but was able to make sure the adjustment did not change when I took them out).

    Quote Originally Posted by nmpeter View Post
    +1 on the accelerator hose lines..they get brittle and leak and the clamps are tricky as they are tiny tiny tiny.
    Any idea on where to get replacement clamps that will fit?

    Quote Originally Posted by nmpeter View Post
    every single carb screws is available
    Might be, but not in parts finder and the dealer did not have that size. I happened to strip the one screw that was longer than all the rest.

  6. #6
    Thanks for the reply.

    Quote Originally Posted by Ken62465 View Post
    New Needles and Seats...check pop-off!
    replace fuel lines
    pull and clean out fuel selector.
    I guess I need to replace the Needles and Seats... did not since did not have a way to check pop-off. Will look into your recommendation.
    Fuel lines were replaced last summer, along with cleaning the fuel selector.

    Quote Originally Posted by Ken62465 View Post
    Lastly...get yourself familiar with the difference between a bog and a hesitation..different feel. A bog the engine will be rich and gurgle in sound until cleared out. A hesitation feels more like a flat spot of no fuel then it bites and takes off.
    What is happening if I go WOT from a dead stop it bogs (has that deep sound of the motor getting ready to stop)... if I leave it WOT it stalls, but if I immediately let off the throttle it will start idling. If I start out at half-throttle it goes without a problem. To me a hesitation is if from a dead stop I go WOT then it does not really go anywhere then takes off - this is not what is happening.

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