I have this ancient MRC Trainer Hawk (Foam plane w/ glow engine) and the engine starts right up and throttles up properly for the first few minutes or so. After a couple of minutes, however, the engine seems to lose power and doesnt throttle up properly anymore. Then, when I try to idle the engine, it dies. Also, when the plane is tilted, the engine seems to lose more power. What gives? Is the needle not set properly or is it the gas tank or what?

Sounds rich on the LSN, what engine is it specifically?

It sounds too lean to me, especially losing power when the nose is tilted up. Losing power after running for a while is a sign of over heating from being lean also.

Yea now that I re-read it I am confused

Here, try this for help http://www.hooked-on-rc-airplanes.co...ning-tips.html

Recheck all your plumbing, especially that inside the tank. Make sure clunk is free and no holes or disconnected lines inside the tank.

Its an Enya brand, like .15 or so. Not a big engine.

What prop are you running ?, too big of a prop can also load the motor too much and make it overheat which will cause a loss of power.

The original prop, which was wood, broke so I got some new synthetic ones that were the same size. I used to have the "scimitar"-shaped props which seemed to greatly aid in climbing power, but theyve since broke and i havent got new ones. Now I just have the normal shaped ones.

Originally Posted by Chris_S

Its an Enya brand, like .15 or so. Not a big engine.

Uh oh...that might be your problem. If it's an SS15 then they're ABC but if it's a 15-V or earlier then they use an iron piston which needs a fuel with at least 20% all castor, normal RC fuels will make them overheat/wear out from lack of suitable amounts of decent oil.

A friend of my dad's who flies RC or something suggested a while ago that overheating could be a problem. So is that 20% castor fuel still available? And btw, the link was very helpful... Never knew that part about never letting it run lean.

There are a number of companies in America that make a suitable fuel for the Enya so your best bet is to go to different company's web sites and check out their blends. Don't bother going to Morgan though, I know for a fact they don't have one. Try Sig, Fox or similar. Those Enyas are very good engines and if you treat them right they'll last practically a lifetime .

If its lasted this far, with the amount of abuse it has been put thru, I think it'll be fine. At least I hope so, anyway. It used to be my dad's and he tinkered around with it awhile when he was a kid, but he never got around to flying it.

Its not the fuel it's the mixture of fuel and air...sounds too lean to me too much air.....ask a more seasoned flyer to help you tune your engine

btw tune the engine (needle setting) so that when you hold the plane with the nose at about 45 deg the engine runs fine; this is ussaly a few steps rich (open) then full power when the plane is horizontal.
btw is your prop a 8*4 size?