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914 wont go over 3000 RPM

in 912 / 914 Technical Questions 7 years ago
Last year we synced carbs on my buddies 914. Ran great. Month later was rattling the gearbox and missing. We found a sunk float and changed all four. He let the plane sit a while (7 months) and it ran ok a couple times now it just wont go over 3000 rpm. Idles smooth, vacuum at the intake manifolds is the same at idle (still need to check at WOT.) I own a 912 and am learning the differences between the 914 and the 912. Fuel pressure regulator to enrich under boost all makes sense. Im thinking the float bowl gaskets might be leaking and am going to use a smoke machine to pressurize the intake to 2 or three PSI and see if we get smoke coming out anywhere. Anyone have any tips or seen anything besides float bowl gaskets causing a symptom like this? It runs smooth, just wont go over 3000 RPM. Like the air filter has a massive restriction but we ran it with it off and makes no difference. The engine has 150 hours on it so it shouldn't be anything too stupid one would hope. Im of the mind to double check everything we touched and from what I have read the float bowl gaskets can cause a symptom like this.

Thanks for any input anyone has.

  • Re: 914 wont go over 3000 RPM

    by » 7 years ago

    Where was it sitting for 7 months??? mice.... spiders.... squirrels also like to chew through things... had a squirrel get in the our car in the driveway chew through 2 wires last week .... we have had squirrels at our house for over 20 years and never chewed anything....so... go figure... at least the little dude chewed through wires in the front of the engine.....I guess so I could see what he did.... :) anyway just a thought.
      
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  • Re: 914 wont go over 3000 RPM

    by » 7 years ago

    Here is what RobSeaton had to say about that (on another thread, just search "engine will not go over 3500") This fixed the problem.

    you will not see any leaks or stains as the fuel is comes out as a vapor (unless you use avgas as it has a lot of blue dye)
    check if the float bowl sealing surface is even (check with a "straightedge". If the bowl plug has been over-torqued the bowl will be distorted and you will not be able to seal it.
      
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  • Re: 914 wont go over 3000 RPM

    by » 6 years ago

    During maintenance work on the ROTEX 914 engine, we dragged the bolt of the carburetor float chamber and the fuel no longer flowed into the jet due to the fact that the jet blocked the jet the engine did not want to dial above 3000 rpm. Break through the bolt of this bolt it is 5 newtons by hand and replace the gasket of the float chamber as she shrank
      
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  • Re: 914 wont go over 3000 RPM

    by » 6 years ago

    Having a simular problem with a 912 ULS, has water in bowls, serviced both bowls and now very rough ops (2-cyl) near or at 3900...? Ran engine for 1/2 hour with tape over the oil cooler to get it up to 175 ish. Start up and mid power all normal...?
      
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