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I need help timing a 3w-546

Discussion in 'Giant / Scale ARF Build Threads' started by RC Parts For Less, May 23, 2020 at 11:03 AM.

  1. Hey Guys,
    I am at my wits end. I am very familiar with DA and DLE motors but I only have a couple 3w motors. I purchased a 546 for a project I’m working on, it was used because the budget didn’t allow for a new motor. I bought this motor trusting the person selling it which I have found was a huge mistake. The carbs that came on it didn’t fit and were not the carbs meant for the motor. The ignitions also were not the proper ignitions for the motor. I have purchased a new intake as well as one carb to mimic the motors. I also bought the correct ignitions for the motor. So after all that now to the issues. I have mounted the intake and carb, that’s all good, I assume, won’t know for sure until I get it started. I also put the new ignitions on , this has a two magnet set up. The information that came with the ignitions is vague at best. The hall sensors are the ones that came with the motor, the ignitions have spark so I know they work. I have tried starting the motor but have not had any luck.
    My issue is I am not sure if the motor is timed correctly. To make matters worse there are 4 magnets on the hub, not sure why. Anyway, it looks like the magnets are somewhere around 40 degrees after TDC as seen in the instructions. I cannot get the motor to pop or show any signs of life at all. If there is anyone out there that has some documentation for timing a 3w motor PLEASE, help a fellow rc’er out. I want so bad to hear this monster roar to life. I need to understand the timing and what to put where. I will send or post any pictures you guys need I am desperate here so if you might know what I should do please let me know.
  2. dhal22

    dhal22 GSN Sponsor Tier 1

    I use the 'Easy Button', I send my engines to Gerhard (Aircraft International). He makes my 3W's sing like a sewing machine. Therefore I will not be much help as I don't work on mine.
    AKNick and pawnshopmike like this.
  3. AKNick

    AKNick 150cc

    Isn't that what @stangflyer does too...??
    There isn't a whole lot out there that I could find for information. I cannot even find a specific engine manual, just the generic.

    How are you starting this engine? Sounds like there is an arming sequence through rotating the propeller through? As in you cannot start this puppy by hand. Hmmmm not sure buddy.

    You can contact them directly:
  4. You're making a mountain out of a mole hill, in my opinion.

    First, the carbs don't know - or care - what engine they're on. If they're approximately the right diameter, if the vacuum port meets up with the diaphragm, if they're not leaking air or fuel, if the passages are not blocked with congealed oil deposits, and if fuel flows when you prime it, then the engine will run. Maybe not perfectly, but it'll start and run.

    Second; this, of course, presupposes the ignition is supplying a spark. Once again, as long as it's got the spark for the firing sequence (probably an alternatively firing boxer, where the two front fire at the same time and then the two rear fire at the same time), then because in essence, it's just a spark unit for a twin but with enough juice to arc two plugs at a time, then the ignition module doesn't have a clue what engine it's on, either. Please don't overthink this; it's just a simple 4-cyclinder 2-stroke engine . . . and it's not complicated.

    Third; and as always, does it have compression? Yes, this is basic, but if it doesn't have compression it also isn't producing a vacuum signal for the carbs to flow fuel. If the rings aren't sealing to the walls of the cylinders, then it's also not creating a vacuum signal so maybe add a tiny bit of oil to each cylinder to help it seal (if it's totally dry). Anyway, if it's getting fuel, and makes a spark at the right time, and has compression, then it's going to start and run - physics! Oh, speaking fo fuel, regular pump gas and 32:1 oil is all it needs but the gas can't be old, capice?

    Bottom line? Answer these three questions, does it have fuel, spark, and compression in the affirmative and the engine will start and run. Once it's doing this, you can fiddle with tuning it. And if this is all more than you have experience with or feel comfortable ascertaining, then by all means do what someone above suggested, send it in to Aircraft international where they can quickly sort it because of their great experience. Speaking of experience, if you're reading this and are not super experienced with engines 'and' would like to know a bit more, I produced a DVD on the subject to help get you up to speed (and making it perhaps the best $20 you'll ever spend).

    aboutENGINES DVD - https://www.promodeler.com/RCB003
    AKNick and dhal22 like this.
  5. AKNick

    AKNick 150cc

    Had no idea you had a video out there! Always something to learn. You got a teaser video?

    As far as the timing question, I still think it would be beneficial to contact 3Dub directly for information If you hoping to do it all yourself. When I'm defeated it does usually mean to call the pros or pay someone else to do it. You can check the timing when you get it back to verify how it ended up.


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