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Dennis Somers

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About Dennis Somers

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    Beginner Boater

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    G (greater) T (Toronto) A (area)
  1. Dennis Somers

    Setting timing on a CMB alpha 27

    .0472" to .0512"
  2. Dennis Somers

    Quikdraw Pioneer Motors

    Hello Mikael. The stock 27 Pioneer is a good motor for that European class. The competition would be the TK. Properly modified is a completely different story.
  3. Dennis Somers

    Sure seems dead around here.

    Well, from this ol fart to many more, social media and computer phones have killed printed forums. People don't have the time and can't be bothered. Also, how many people ask for advise, and ya never hear anything back, including a thanks? They just want an answer, and they're gone! Ya I know; OLD and GRUMPY LOL.
  4. Dennis Somers

    Extending the carb out?

    I would be VERY surprised if they hadn't, on their experimental race engines. But they are reed induction and carb distance doesn't have the same effect as piston port. Keep in mind, their production motors also have to fit under compact hoods, run quiet, and the 2 strokes don't have tuned pipes. And they are relatively moderate RPM machines. Commercial outboards don't make anywhere near the 4 1/2 + HP per cubic inch that our little guys do.
  5. Dennis Somers

    Extending the carb out?

    In the utility engine business, Zenoah and all the rest of them, want to build the most power in the smallest/lightest package ( that's what sells ). To that end, they make everything to be compact, and get the best compromise of power/torque in an end use friendly configuration. The intake, as well as all the other systems are not race perfect by any stretch. We, as builders/modifiers, have to recognize the potential and the limits of the entire engine. And there is little to nothing, that can't be tweaked for our purpose. As Mercury Racing says, the race is never over. LOL
  6. Dennis Somers

    Extending the carb out?

    John I'm glad you are happy with it and that it works for ya, and I'm NOT trying to change your mind. I too have a 632HP S/B street eng. with two 660 center shooters on a tunnel ram that pulls HARD from 3500 to 8000+. However, the intake dynamics of a 4 stroke race eng. at any RPM, are far different from a pressure/pulse 2 stroke firing every revolution. Flow IS flow, and I understand what your vision is. But your ration-ale for atomization is off. The fuel is atomized by the addition of air right at the venturi. After that, the heavier components of the mixture ( gas/oil ) are trying to separate. The longer and more convoluted the path, the more time/surfaces aid in that separation. That, together with the intake reversion on every cycle, combine to reduce velocity and increase the separation. Yes, we have tried it! And it runs. But not as well as it can. Just my building experience since 1961. ENJOY IT!
  7. Dennis Somers

    Extending the carb out?

    We have done extensive testing on intake length and volumes. And whether it helps performance or not, just a heads up; When you have a larger volume of atomized fuel between the carb and the case, when you get out of the throttle the engine can continue to rev - using up that extra until it is spent. This delayed reaction can be trouble in a heat race situation.
  8. Dennis Somers

    Mystery pipes?

    Hey Terry; They both appear to be Mac aluminum torque enhancing ( banded mid section ) nitro pipes. The larger might be for .67 to 1.01, and I don't know about the app for the smaller.
  9. Dennis Somers

    White Gas in Gas Hydros

    Mr. Clark, if you want to wet your feet in gas boats and don't like monos, the gas cats are fun. I would suggest you get a stock Zenoah of whatever displacement would fit into a given race class in the future. It can be modded by any number of guys afterwords, if that's what you wanted. The stock motor would get you used to the gas boat handling, as well as the general use and maintenance of the gas motors, at a fraction of the modifieds. In some cases, you can use the same props and have them pitched up as needed.
  10. Dennis Somers

    White Gas in Gas Hydros

    Finn, white gas ( Coleman ) is a good choice for most of our marine gas motors. Higher compression billet models may need more octane. The reason people may worry about low octane is detonation damage. Two things that detonation need to exist are time, and space. Mostly detonation developes at lower RPM and high loads. Our engines idle at 6 to 8K ( redline for a lot of other engines ), and run 90% of their time at 18 to 20K+. Our combustion chambers are around 1.2 to 2cc. and a 10mm. plug takes up a lot of that. Detonation is 2 or more flame fronts developing within a chamber, that collide to produce uncontrolled violent explosions. At 18 to 20K, inside that tiny chamber, there is no time or space for that to happen, UNLESS other criteria are out of whack. Overheating, advanced ign. timing ( most of ours are pre-set ), lower speed lugging from a too-large prop, or lean mixture from settings or restricted fuel flow, can cause detonation, outside of the octane requirement. A lot of modellers look at octane and relate it to other much larger motors. Our little gassers are in a field of their own. Those larger engines run much lower RPM, and their combustion chambers are huge ( giving them the time and space ). I hope that helps to understand "why".
  11. Dennis Somers

    Piston and rings

    The compression distance is smaller ( Zen ) and the skirts are shorter, as well as what Rudy said; requires changes.
  12. Dennis Somers

    what is the fastest oval class impba

    Adam, just go to the IMPBA site and look up the current records. And if you can't tune it and drive it, it will be the most extreme oval rigger on your shelf. LOL
  13. Dennis Somers

    CC fuel bags

    The CC Racing bags were 500 cc Baxter bags, and are still considered the "gas standard" for gas boats. The key to keeping them soft is to keep them filled completely with fuel ( no air pockets ) while not in use. And a short time in the sun, and they are soft again. And for guys who have to "Winter" their boats for several months, they should swap for new every Spring. Burping a bag ( getting air pockets out ) is as simple as reversing your fill pump. And don't pump fuel in, until you have back pumped to get the air out of the fill line. Hanson still lists the other bags on Al's site ( currently out of stock - phone call ). They are 16 oz. ( 473 ccs. ). The Gizmo bags have been reported to have problems in the past. Hard tanks are fine for nitro, but bags can be placed anywhere for balance changes for weather conditions. There's no venting issues or worry about keeping water out. Bags or hard tanks, everyone has the choice.
  14. Dennis Somers


    Phil, it won't make any difference except possibly to get it up off launch or slow mill. And that's because at speed, the bottom of the strut barrel is completely free of the water. A good prop shaft C/L height is between 5/8" and 3/4" above the sponsons on a set-up table. Be sure to use a skegged strut and off-set the drive 1/4" to starboard.
  15. Dennis Somers


    Works fine on my end Jim ...