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  1. #1
    dduck dduck1628's Avatar
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    Question Some performance advice please.

    I recently purchased a 2004 1300R RRE , 45 hrs. My first yamaha. First ride, I had no accurate speed and rpm, but it would barely pull away from my 62 mph XPL. It would load up and bog out of the hole, smoked like crazy, and used a ton of gas. Check the compression and it was 125 lbs in all three holes. Found oil pump cable had come off of the bracket, reinstalled and adjusted to spec. Found EFI was set to 9 1 9 1, yes 9 1 9 1. Set EFI to an initial adjustment of 6 6 1 7. While the pipe was off I pulled and inspected the reeds and made sure the throttle was going full open and made sure the screens were out of the throttle body cover/housing. Cleaned riva power filter and prefilter, (both were covered with oil). Installed new plugs, (gaped and indexed). Noticed some cavitation damage on the pump stator at the 3 o’clock and 9 o’clock positions. So I pulled the pump shoe and resealed with 4200, also cut down plugs so that the shoe would fit tightly against the hull. Shimmed down the front of the rideplate since it was around .25” above the hull to start with. Ground down the rear mounts. Also ground down pump, nozzle and notched the rideplate for clearance. I was able to angle the rideplate 4.75 degrees. Set RIVA sponsons from lowest to the middle position. The next ride was noticeably faster. Now pulls pull away from my XPL with ease, but would porpoise with the slightest amount of chop. I installed a tiny tach and bought a GPS. Tweaked EFI to a final adjustment of 3 5 1 7 for best RPM and to keep engine from loading up and bogging off idle. Still loads up and boggs a little after extended idle, but I’m a little concerned with going too lean so I left the idle mixture setting at 3. Shimmed the stock plastic stock trim tabs down .120” with shims I made from plastic “for sale” signs. porpoising gone.
    Next run was 68.5 mph, gps, in opposite directions at 7080 rpm. Air temp. around 80 and water temp around 80. Sea level. This was done early in the day. Based on what riva advertises on the level 1 I was expecting to see 70 mph and 7280 RPM. I would have been happy with 7200 RPM. .Found PVs out of adjustment. Cable that pulls PVs open was very loose. Adjusted to spec. Installed wave eater clips and couplers. No change, but temp was around 88 and humid. Water temp was around 80. Check for exhaust leaks, none. Last night I pulled the head to make sure the engine had not been sleeved incorrectly or something. It appeared that work had been done since wires were not in there clips, zips ties missing, etc. All ports matched up, everything looked great. It appeared that this engine had never been apart. Maybe some one did some sloppy work installing the d-plate or something, who knows. While the head was off I made a piston stop, found TDC for each cylinder, and made sure all cylinders were 120 degrees apart. All checked good. I realize that the weather is hot, but 200 RPM low? I plan on doing some more mods, but not until I’m sure that there is nothing wrong. The way I see it there are only three other possibilities. 1. Riva’s level 1 spec. is not a good indicator. 2. The impeller pitch is off. 3. My expectations are too high. Can anyone offer some advice? Have I overlooked something? Is this normal performace? I’m a bit of a perfectionist when it comes to things mechanical and I’d like to put this to rest so I can move on. Thanks in advance…
    D.Duck


  2. #2
    Nothin' runs like a Deere IowanGPR's Avatar
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    sounds like you know what you're doing. i'm sure there will be some guru's here to help you- i've only been wrenching about a year so i'll let them handle this one- good luck and welcome to the forum.

  3. #3
    Happily Self-Employed WFO's Avatar
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    Welcome to the forum.

    I would run those sponson blades all the way down, and you can re-adjust the tabs.

    What exactly are the mods on this boat ? Filter, controller, plate, grate, sponsons, prop, nozzle, and D-plate ? Freeflow ?

  4. #4
    dduck dduck1628's Avatar
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    List of mods

    2004 gp1300r RRE
    1. Riva Ride Plate angled to 4.75 degress
    2. Pump seal kit
    3. Pump shoe bolt holes filled
    4. Stock Trim tabs shimmed .120"
    5. EFI Controller
    6. D plate
    7. Free flow exhaust
    8. Cat chip.
    9. Rive sponsons middle position.
    10. 87mm nozzle
    12. Set back 13/20
    13. RIVA GP1200R/1300R Top-Loader Intake Grate
    14. Power Filter Flame Arrestor
    15. Solas concord setback impleller 13-20

  5. #5
    Happily Self-Employed WFO's Avatar
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    Quote Originally Posted by dduck1628 View Post
    2004 gp1300r RRE
    1. Riva Ride Plate angled to 4.75 degress
    2. Pump seal kit
    3. Pump shoe bolt holes filled
    4. Stock Trim tabs shimmed .120"
    5. EFI Controller
    6. D plate
    7. Free flow exhaust
    8. Cat chip.
    9. Rive sponsons middle position.
    10. 87mm nozzle
    12. Set back 13/20
    13. RIVA GP1200R/1300R Top-Loader Intake Grate
    14. Power Filter Flame Arrestor
    15. Solas concord setback impleller 13-20
    You are no doubt a pefectionist Duck.

    The boat would run the "advertised" speeds in cooler weather. I personally dont think there is anything wrong. The prop is a little big for this heat, and for this level of mods. Thats Riva's fault. Also make damn sure they didnt put a power core in there.

    I would get rid of the filter sock. Also the freeflow will increase holeshot and mid power, but drop your top rpms a few over the stock sound suppression (50 or so). Drop the sponson blades down and put the tabs back flat against the hull. Get it low on fuel and see how it performs. Forget about the plate "angles" and use shims to get it right on the edge of loose, then add a little to the rear of the plate. Dont be afraid to shim the front of the plate down first, just above the sides of the shoe (.020-.030), then work the rear.

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