ST G90 overheating
05-22-2002, 10:39 PM
#1
ST G90 overheating
*I would like so advice here since i am stumped but i want to bring you up to speed. I had tried everything possible. Plugs, Fuel, Fuel lines, New Fuel Tank, Different carb (Perry), Props, the whole thing. Engine would run a couple minutes in the air and quit. I sent it off to Hobby Services and they are sending it back saying nothing is wrong.
* I am running a BCm Pitts muffler. Now I asked my local Hobby guru about this. He agreed with hobby services in that just because a muffler is made for a certain engine does not mean it will work right.
*He stated that not enough back pressure from this pitts would cause an overheat. Here is what he said to do and i would like some comments. Get my engine dialed in as best i can. While at full throttle put on a glove and plug up one of the exhaust tubes. If the engine goes immediately rich, this is a clear sign of not enough back pressure and that I should plug up one hole permenently and re-tune. What do you think?
* I am running a BCm Pitts muffler. Now I asked my local Hobby guru about this. He agreed with hobby services in that just because a muffler is made for a certain engine does not mean it will work right.
*He stated that not enough back pressure from this pitts would cause an overheat. Here is what he said to do and i would like some comments. Get my engine dialed in as best i can. While at full throttle put on a glove and plug up one of the exhaust tubes. If the engine goes immediately rich, this is a clear sign of not enough back pressure and that I should plug up one hole permenently and re-tune. What do you think?
05-23-2002, 01:22 AM
#2
My Feedback: (5)
ST G90 overheating
what is the mounting like- that is how much air flows over this engine? if it is mounted in a cowl it may not be getting enough cooling.
also- the super tigers run best when they are set up so they have a smoke trail in the air. not super rich but enough to see a smoke trail.
be sure to check the needle valve setting by holding the nose of the plane straight up to be sure the engine doesn't slow down- if it does when the plane is vertical then the engine is set too lean.
also- how long have you run it? my tigers need at least an hour and a half of break in before they settle down. that is they do not really idle well until they break in some, and after an houor so you can really start tuning them in- especially in the midrange. until they break in you need to keep the idle up as they do not draw fuel real well at idle and they will shut down.
also- use an idle bar glow plug. i have used fox longs but also recently i have used a short k&b plug with an idle bar which works well.
i have used the bisson pitts muffler with my super tiger g90s and have not seen any more tendency to overheat than with the standard quiet muffler. i am not saying he is wrong but i have not seen a noticeable difference myself.
also- the super tigers run best when they are set up so they have a smoke trail in the air. not super rich but enough to see a smoke trail.
be sure to check the needle valve setting by holding the nose of the plane straight up to be sure the engine doesn't slow down- if it does when the plane is vertical then the engine is set too lean.
also- how long have you run it? my tigers need at least an hour and a half of break in before they settle down. that is they do not really idle well until they break in some, and after an houor so you can really start tuning them in- especially in the midrange. until they break in you need to keep the idle up as they do not draw fuel real well at idle and they will shut down.
also- use an idle bar glow plug. i have used fox longs but also recently i have used a short k&b plug with an idle bar which works well.
i have used the bisson pitts muffler with my super tiger g90s and have not seen any more tendency to overheat than with the standard quiet muffler. i am not saying he is wrong but i have not seen a noticeable difference myself.
05-23-2002, 11:25 AM
#4
My Feedback: (8)
Join Date: Dec 2001
Location: Colorado Springs,
CO
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Ringed Engine
If you tried to speed up the break in and ran her hot one time too many, you may want to take her apart and check out the piston, ring, and liner. If liner isn't scored, you may want to replace the ring (4-5 bucks cost) and try again to break her in. Ringed engines need VERY Rich breakings for a long time. 1 to 2 hours is not unusual.
