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Is it worth the $$$ to replace a 8hp with a 9.9hp?

Discussion in 'Boats and Motors' started by tech187, Apr 2, 2005.

  1. I have an 8hp 2 stroke johnson on my 14 foot deep V. It does not seem to push the boat around very well at all. Have considered replacing it with a 9.9hp, but I am not sure if another 1.9hp would even be worth the bother. What do you all think? Thanks for any info.
     
  2. How wides the beam? Ive had 2-14v, and there diff by the width. Might be worth findin a used 25hp and using the 8 for a kicker.
     

  3. Not sure about the beam width. I will have to measure. I primarily fish Hoover and other 10hp limit lakes, so a 9.9hp is the largest motor I can really consider.
     
  4. johnboy111711

    johnboy111711 SOLID MEAT

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    9.9 4-strokes are very nice...depending on the weight of the boat you may need to get a new prop with a different pitch to help the boat plane out.
     
  5. freyedknot

    freyedknot useless poster

    you would be better off getting a 9.9 w/ 15hp carbs installed.check around you may be able to upgrade your carbs to a 9.9. four strokes are a little slower than the 2 strokes and usually weigh a bit more. what is the hp rating of your boat?
     
  6. The boat has a 25hp limit. A different prop might not be a bad idea since this boat does not even come close to planning. New 9.9hp motors are around $2000.00 so I will probably just deal with this one until I replace the entire boat.
     
  7. sparkywest28

    sparkywest28 sparkywest28

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    what ever u do dont buy a 4 stroke and think it will get more power.the 4 stroke has 1/2 the torque.try new prop or maybe add a hydrofoil to the lower unit.that will give it more lift.
     
  8. UFM82

    UFM82 The one others want to be

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    Although the 9.9 would be a 20% increase in horsepower, I don't think you're going to see a huge difference in speed. I have seen some 14 footers plane with a 9.9 but they have been flat-bottom johnboats with large planing surfaces. A Deep-V displaces more water and is harder to get up on plane. The motor may very well have the guts to keep it on plane but it may not be able to get it there in the first place.

    The fact that you need to stay under the 10 hp limit dictates a 9.9 with the 15hp carb kit. It can be done relatively cheaply and really isn't all that hard. I would look for a used 9.9 for under $1,000 and have the kit done. You should be able to find a decent engine for that and spend another $200 and you have the power to plane your boat. Is it a heavy 14 footer like a Sea Nymph or is it a lightweight boat? I have seen big differences in boat weights in the 14 foot class.

    Even with a 15hp output, don't expect a lot of speed. I'm guessing high teens maybe?

    UFM82
     
  9. MAINAH

    MAINAH Little Member

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    I have a 14' alum (not so deep V, the back 1/2 of the bottom is pretty flat) with a 9.9 Merc, and with my wife, 2 kids and I in the boat she planes out nicely. It really scoots when I'm by myself. I am considering that 15hp carb kit option though. I'd like to go out on Erie with a little more power. Good luck.
     
  10. crankus_maximus

    crankus_maximus Crankus Baitus Maximus

    I disagree with the 4stroke torque ratings. My Honda 9.9 pushes my 14ft semi-v with my wife and I and our gear in it and we stay on plane. With myself in it alone I would guess between 18-20. It really scoots.

    The smaller 4-strokes give you one advantage over the 2-strokes in that you can run all day on a 3 gallon gas can. You don't have to mix the oil and they are much quieter. Just the opinion of a real 4-stroke owner :)