Já não me recordo da origem inicial deste texto (foi na altura em que o meu Zenoah 23cc custava a pegar) mas encontrei-o hoje aqui perdido no meu disco rígido...
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Question
I recently purchased a Pro Boat 1/8-scale Miss Budweiser RTR hydro, and I'm having difficulty starting the Zenoah engine. Sometimes, it's tricky to hold the fiberglass hull steady as I pull the Zenoah's recoil-starter, and it always seems to take at least 20 to 30 pulls (or more) to get the engine running. I've tried adjusting the two carb-mixture screws both in and out. I use regular pump gasoline and an oil/fuel ratio recommended by Pro Boat, and I have checked the engine's spark-plug gap for proper clearance. What am I doing wrong?
Answer
A The Zenoah's high compression ratio makes it difficult to crank over easily, but by following a few simple tips, you'll have your Pro Boat hydro's engine started with only a few pulls. To start it, hold the engine in your hand between the front of its water jacket and the recoil-starter housing. Rest your body or a leg lightly against the hull sponson (making sure that you aren't anywhere near the prop) to improve your grip. This stance offers a stable platform for starting the boat; it will greatly decrease the effect of the engine's strong compression and, consequently, reduce the pulling effort required to start it.
Since you've had a lot "pull time" on the engine, I recommend that you remove the spark plug and see whether it looks wet; that would indicate that the Zenoah's fuel/air mixture might be too rich. Since you've changed the settings on the mixture needle screws, you'll have to reset both before you try a new starting technique. Turn them clockwise slowly until they completely seat against the carb's body, and then rotate each one counterclockwise 1½ turns.
Once you're lakeside, make sure that your radio system is working properly, the fuel tank is full, the carb's primer bulb has been squeezed until it's full of gas and you've positioned your boat and its stand on a hard, level surface. Place your finger over the carb inlet hole, and give the pull-starter no more than three quick pulls. After three pulls, you should see a little fuel on the finger that's covering the inlet hole, and the Zenoah engine is now primed for starting. Squeezing on the primer bulb won't flow enough fuel to start the Zenoah; the finger/choke trick is the only way to be sure that gas is entering the combustion chamber.
Uncover the inlet hole and pull the recoil cord until the engine makes a quick popping sound. If, after several pulls, you don't hear that pop, you'll have to alter your transmitter's throttle setting to the half-open position. This is where a buddy comes in handy; While he holds the transmitter at this setting, tug the pull-starter a few times until the Zenoah comes to life.
Under no circumstances should you continue to yank on the pull-starter until you're red in the face and out of breath, as you'll probably flood the engine and blister your hand! If the engine is flooded, you'll have to remove the spark plug, place a rag over its hole and pull the recoil-starter cord to clear it. Then, reinstall the plug, and the Miss Bud has been prepped for starting. In some cases, if you hold the throttle wide open while you give the Zenoah starter a quick pull or two, you'll clear any excess fuel out of the engine and improve your chances of getting your hydro to run easily. Once the engine has started, it will be running at high idle, and you should limit this run time and get the boat on the water as soon as you can.
Depending on the weather, your fuel/oil ratio and any modifications, the final settings on each of the carb's mixture screws could be between 1/8 and ¼ turn out from your initial setup. Luckily, the Zenoah has a very short break-in period, so these settings will stabilize within a few tanks of fuel. All of these tips can be applied to almost any Zenoah engine, and once you've mastered them, you'll be able to get your 1/8-scale hydro up and running as easily as you put more gas into its tank!
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