toxic231 engine pulsating up and down

[skiboy]

Yes the other day I was flying my Spectra G arround and the engine started pulsating up and down and when I got it about a foot off the ground it reved up and tilted over nothing major, boom, blades, flybar servo gears, tail blade, and skids, but anyway got parts and working on gear sets and noticed that the 611 gyro came up bat low, yes I did not check my bat level so I figured that that was the problem . Repaired the heli got her running and started to go up and the engine was pulsating again, took the cover off and white tied hose fittings and found the the cap on the fuel jug was really loose , tighted it up went to fly again and the same thing with the engine pulsating any thought s on this , any help would be greatly app...

[ddavison]

Check carb to see if it is loose ,check for air leak between the carb and insulator, graphite plate. Check insulator to see if it is warped. Dave

[skiboy]

Ok carb is not loose , but how do you check to see if there is air leak between the carb and insulator an graphite plate????

[rbort]

Check the throttle servo and make sure its not gone bad. You may need to hover (if possible with this oscillation) without the canopy and observe the throttle servo horn in a hover and see if there is any unwanted movement. Very possible you have a bad servo.

Running out of a battery should be a no no! I'd say get an on-board generator but that's just me!

-=>Raja.

[Peter]

To test for air leaks , idle the motor , and spray the suspect area with wd40 (lubricating spray ) or similar .. You'll soon know if theres a leak!!

[skiboy]

Thanks guys I app. the info , I will give it a try this weekend about the air leak and I am thinking very seriously about the generator with the voltage display, after the weekend I will tell the results that I got ..again thanks..