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  1. #1

    Join Date
    Jun 2015

    Troubleshooting a `99 SLX

    So after impulse buying a `99 SLX without fully checking it out, I'm confronted with some problems. TxPro1200 has been giving me some suggestions on what to check, hence some of what I've gone through in the description below. I wanted to put this in front of everyone, as well, in the hopes that more eyes on it will get me to the root cause sooner. I'm also interested in knowing who in the DFW area would be good to work on it if it comes to that. So here it is...

    After first picking it up, I dropped a new battery in and drained all the old gas. After much cranking it fired up. Took it to the lake. It ran good with a couple of stutters for the first few minutes. Then started bogging down. Wouldn't get the RPM up, but would idle pretty much ok.

    Brought it home. Replaced fuel switch, all fuel lines, check valves, and put rebuild kits in the carbs (OEM from Used medium springs in kit that matched the original. Fired it up in the driveway and ran ok, but RPM ran up crazy high. Realized butterflies were open too much with no throttle applied. So I adjusted them down. Got a consistent 2350ish RPM on flush hose in the driveway. Low speed set screws have never been moved. Has no high speed screws. Also replaced the crossover exhaust hose because the old one had soft spots and I wondered if it had collapsed inside. (Thread showing hose I put in - Hope it's not too tall to perform well. )

    So we took it out to Lake Lewisville since Little Elm ramp opened up. Fired up and idles great. Took it out and it jumped up in RPM, but only for the first few seconds. After that, while it seemed a bit cleaner/smoother, it wouldn't jump up in RPM without bogging down and dying if I didn't get out of it. With some playing I could feather it and get 2000 occasionally up to 2400, but it would bog down. Idles perfect (a touch high in the water. about 15-1600) for as long as you like. Starts quick and idles easy. Just can't get it to take off. Let it rest a bit and it will jump for a second, but minimally. Next after trying it at the lake, I brought it home and hooked up to the flush kit to run some clean water through it. Again, it fired up and sat up at 5000+ RPM. Odd as hell. Was getting too late and didn't want to mess with it for the evening.

    Took it out tonight. Still starts and idles fine as long as you like. I could feather it and kind of keep around 2000rpm. Bogs and dies if you try to go any higher. Loosening or even removing gas cap didn't seem to make a difference. Felt down by the plugs. Front one jug is coolest, followed by middle, and rear is the hottest. Pretty even progression from warm to hotter front to back. Plugs look pretty nice and event. It really kind of feels like the carbs need work. I remember the butterflies were impossible for me to get even and they were progressively more open as you move back (three carbs connected at the idle screws I believe). I can say that when I put in the rebuild kit, we didn't mess with the low speed screws. Only the idle screws that connect them (probably screwed that up). I have no idea about pop off pressure, float or whatever carb settings, so I'm wondering if they need a proper tuning since my basic rebuild. It's very consistent in what it does. It does also seem to have no problem revving out of the water. BTW, current tank of gas is same since I drained all the old gas. Current does have some Seafoam in it.

    Here's what the plugs look like after the above testing...

    Right after pulling out...
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    Very quick wipe off with paper towel only.
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    I have a couple of other problems that I'm not nearly as worried about till I get it running solid...

    - MFD works and is nice and clear, but left button doesn't seem to work. When running it shows correct (at least it looks correct) for gas, oil, RPM, speed. And red light shows ok if you reset by removing from battery. Trim does not show adjusting on it, though.
    - Trim motor seems to be dead. I put a 12 volt battery direct to it. My kid felt it while I hit the button and said he thought it might be trying to move, but it's frozen. For now, I just manually put it in the middle.

    Thanks in advance for any help, knowledge, or info you can provide.

  2. #2

    Join Date
    Jun 2015
    No one?

  3. #3

    Join Date
    Jan 2010
    london england
    My pro 1200 wouldn't run properly in the water,till I disconnected the MFD,then it went like a rocket.
    Replaced the MFD and its been fine since.

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