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Thread: 1989 Carrera (454) Jet Specs and Problems

  1. #1
    Paul407
    I bought a 1989 Carrera Open Bow, Jet, Original 454, last season. It ran OK (simply put) at the river during the summer but would often hesitate and "ping" under a foot mashing or heavy load (8 passengers). I had the carb rebuilt (flow tested, etc.) and put it back on. Only helped a little bit. I then replaced the plugs with "hotter" set and this only helped a little bit. I also replaced the distributor since it was mechanical and threw in a new coil for good measure. Still no real improvement. I was told that my #7 Cylinder plug was very fouled and this could possibly be from a "flat spot" on the cam or a couple other reasons ($$$).
    If anybody has heard of this, please let me know. Also, since the boat still has the same hesitation problem, I can't believe that I would be the only person to experience this. Any suggestions would be greatly appreciated. Also, I live in Orange County (CA) and any recommended shops would be helpful.

  2. #2
    DOHARA
    PAUL ARE YOU SURE ENGINE IS COMPLETELY STOCK? HAVE YOU DONE A COMPRESSION TEST TO SEE IF ALL CYLINDERS HAVE GOOD COMPRESSION? WHAT IS TIMING SET AT? WHAT KINDA FUEL 87 OR 91? COULD BE ONE OR ALL OF THE ABOVE, BUT THESE ARE THINGS TO CHECK BEFORE YOU TAKE ENGINE APART. I WOULD DO A COMP. TEST AND LEAK DOWN TEST AND MAKE SURE TIMING IS RIGHT BEFORE GOING ANY FURTHER.

  3. #3
    Wet Dream
    My first check would be the timing. The second thing I would wonder about would be is there excessive carbon build-up on the valves or heads? This could lead to heating the carbon and causing a pre-detonation problem in the cylinder. Anyone else think this might be it?

  4. #4
    Paul407
    I had the timing set when I had the new distributor put in; Running only 91 Octane in it. Was told by the old owner that it was completely stock, as it came from the factory. No compression test or leak down has been done. Any local Orange County shop suggestions would be appreciated

  5. #5
    DEL51
    I suggest hooking up a vaccuum gage to the port under the carb.If your cam has a worn lobe or sticking valve the gage will fluctuate.If it does, remove the valve cover and crank the motor to observe the valve train.Check the ignition and make sure your timing is on.Are there any vaccuum leaks? I agree with the other suggestions listed above my post.GoodLuck!DEL51

  6. #6
    Caribbean19'
    Paul,
    I had a similar problem. No pinging, but lots of hesitation under load--especially out of the hole with a skier. I went to DNE Motorsports in Costa Mesa, a couple doors down from MPD. I too had a very stock 454, and had very few options for improving performance without spending lots of $. DNE did a couple of things that made a huge difference. First, went to an electronic ignition, which sounds like you have done. Had my carb blueprinted, which sounds like you may have done. Then, and I think this had the most impact, I got rid of the flat cast iron stock motor home style intake manifold. DNE put on an aluminum intake manifold appropriate for my carb and engine specs. My boat performs like it has a new engine. It practically leaps out of the water, I can pull up multiple skiers, I can hammer the throttle, and all hesitation is gone. One other thing, which may or may not apply to you. When DNE pulled my distributor, the shaft (not sure of the technical term) had corrosion on it. Over the years, water had somehow gotten to it. That too was replaced. Good luck!

  7. #7
    XClutchboy725
    Paul,
    Here's something else to consider.........
    Chevy firing order is 18436572
    cylinders 5 and 7 are right next to each other and consequently so are the plug wires!
    Keep these two plug wires as far from each other as possible in your wiring loom. Also, make sure your ignition wires are in good shape. You could be getting a cross fire here! This would result in firing number 7 prematurely casing detonation! This happened in my boat when I installed nice Stainless Braided plug wires. They looked pretty and all but ultimately I spun number 7 bearing as a result!
    One more thing... How hot a plug are you running? What brand and what number?
    Too hot can create preignition (pinging) as well.
    http://www.goldenplasma.f2s.com/foru...confused53.gif
    just my .02

  8. #8
    wsm9808
    Checking for a worn cam is pretty easy if you want to do it. Just pull off a valve cover and start the motor and watch the rocker arms. If you have a lobe worn bad enough to effect the performance you will see a rocker that is moving quite a bit less than the others. I would also suggest checking the compression, but a worn lobe will not always show up on a comp. test b/c the valve is still opening enough in most cases to still get a good reading at cranking speed, but it will tell you if the valves and rings are all sealing as they should.
    While you have the valve covers off, look at all the valve springs very closely. BBC are very bad about wearing out the valve guides. If an exhaust guide has worn severly it will allow exhaust heat to leak up through the guide bore resulting in a bad valve spring. If this has happened the affected spring will look dryer than the rest and will have a black crusty deposit on them. if this has happened the motor will run poorly and will carbon up the cylinder that has the bad guide.$$$$ the head will have to come off for repair.
    If every thing checks out good on the motor mecanicaly and you want to try a little more tuning on the carb, here are a couple of things you might want to try.
    Jet boats hit full rpm right out of the hole and in a lot of cases need a little differant fuel curve than "stock" carbs are set up for. For example, the accelerator pump is designed for a car that when under full throttle will start at a low rpm and gradually build up speed. Your boat, with its sudden burst of rpm, could be running out of "pump shot" and leaning out under inital full throttle. A lean condition will cause poor power, pinging and hesitation especally under a load. I would replace the pump discharge nozzel with one a couple of sizes larger. Most Holleys have a .026 (it is stamped on the nozzel). If the bigger nozzel helps a little, then get a 50cc accelerator pump kit and install it. If that was the problem you will feel a big differance when you nail the throttle. also if the boat keeps the bow up for a while when pulling up skiers and/or plainning, I would install jet extenders in the rear bowl to make sure the secondarys are getting fuel all the time. Made a world of differance on my boat. Good luck
    Scott

  9. #9
    HBjet
    Paul, if you need the number to DNE in Costa Mesa, here it is.
    949-631-3781
    Feel free to call Dave and just chat with him about your problem, he is very knowledgable and friendly to deal with. Good Luck.
    HBjet

  10. #10
    froggystyle
    Cheerleader! J/K Randy... http://free.***boat.net/ubb/biggrin.gif

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