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  1. #1
    Pwgsx's Avatar
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    1 eninge rev's slower than the other

    Finally after check engine lights and temp issues I got everything fixed for the most part. Now for the last issue that is not resolved that has been happening from day one........Both engines- 155 N/A's start with no problems, both idle at the same rpms in and out of the water, I have adjusted the throttle cables and reset the tps with the candoo and they are almost identical. However if I push both throttles evenly to say to a target of 6000 rpm's, one engine revs to 6000 rpm's without hesitation and the other slowly increases rpm's when it suddenly takes off and stops around 5500rps. No matter where I keep the throttles WOT, halfway or 3000 rps, one engine is always 500 rpms less. Out of the water it is the same, when I start the engines to blast water out after riding, one engine rev's right away, the other putters for a second and then takes off. Since I have 2 engines, I was going to swap the coil packs and see if the symptoms go to the other engine, if not I was going to swap the fuel injectors. Other than that, I will be out of ideas. Help


  2. #2

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    Do you have new spark plugs in it?

  3. #3
    Pwgsx's Avatar
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    yepp,here is what I did thus far as well as a video showing what it does. Also I rebuilt both pumps but the problem was there even before that. Swapped fuel rails, ECU's and Spark plug coils as well as new spark plugs. Also engine temp, exhaust temp, rpms at idle are normal, TPS reset and throttle opens evenly with the other.
    Went to the lake today and the issue is still there. You can see from the 2 videos, the left engine does not even respond much till more throttle is given. When in the water though some things I did notice- When the throttles are both at 3/4 open or even at WOT, both engine rpm's are dead even. The boat tops out at 52-54 mph's. As soon as I back the throttles off though to 4-5,000 rpm's the left engine does not stay even with the other. I could not hit WOT in the video bc the lake was pretty crowded and trying to hold my phone steady but hopefully you guys can see whats happening. Out of the water is the same, cant run them for long but you can see how uneven they are.




  4. #4

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    Wow...not sure? Long shot but what about the switching the fuel pumps

  5. #5

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    Could the gauge on one side be off on readings ? Compression same on both ?

  6. #6
    Pwgsx's Avatar
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    Gauges are good. The engine is what is bogging. At 7000 rpms or more both are dead even. It's the lower rpms under 6000 is where it goes down hill. Both idle and start no problem. I can't find a fuel pressure gauge but that is on my list.
    Last edited by Pwgsx; 07-21-2014 at 10:27 PM.

  7. #7

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    Hmmm.... yea, I'm not mechanic, I'm curious to know whats wrong though. I had challenger 1800 and one of my engines was same, about 500-600 RPMS lower... turned out compression was low on it... I could keep boat on plane with good engine (1 throttle up, other all the way off) ... but when I reversed it, the bad engine wouldn't even keep boat on plane... BUT (and I know yours is not doing this) ... that same engine with lower RPMs was getting progressively HARD to START.

    Maybe some mechanics will chime in and give better ideas.

  8. #8
    Pwgsx's Avatar
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    Could any of these be the cause: MAP sensor, Idle Control Valve or TPS?

  9. #9

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    Did you ever figure out the problem ?

  10. #10
    Pwgsx's Avatar
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    Not yet, got a new TPS sensor, went to remove the throttle body and it was very dirty so it needs to be cleaned. I should know if the new sensor fixes it by this fri.

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