Ok. I am going to offer you some advice here. I too am on a budget and I have been in this hobby since 1984. Here is my 2 cents worth. You will hear all different kinds of opinions here. Here is mine.
1. Bar none the best lasting engine and lasting quality is the O.S. series. You do not have to buy the 40 or 45 AX series. They have more to offer in this size, take a look at the LA,FP or ABC versions. Might check RCuniverse classifieds for these or a good local hobby shop that sells new/old stock engines.
2. Super Tigre (Italy) if you can find an Italian made Super Tigre like the GS-.40. This is a ringed engine and is a powerhouse. it is sometimes tempermental to tune but once dialed in, it is very reliable and will give you years of great service.
3. Magnum pretty good engine, reliable and not too expensive. Good on power.
Thereare numerous others out there that are pretty good.You have the Fox, K&B, Royal etc. Bottom line is, itall boils down to what you can afford and what you can find that is quality. Dont be afraid of an engine that has been used, but be cautious of bent cranks and burnt or worn out cylinders due towrecks orpure negligence. If you are going to buy a used engine pull the muffler off and look at the cylinder. It needs to be just showingsome signs of a brownish color on the side of the piston. If it is black or there are severe scratches on the cylinder wall, put it down and move on.Rotate the prop and feel the bearings turning as you turn the propellor through. It shuold feel smooth, if it feels gritty or rough as you turn the prop through the bearings are worn and need replacement. Look inside the carb venturi and see if the spray bar is straight and look around the crankcase where the carb bolts are holding the carb in. Make sure there are no cracks around that area. If there are it more than likely has been in a crash. These are just a few visual inspections you can do to ensure you are buying quality instead of someone else's junk.
Do some research on the RCU forums. Here is an excellent link for you go there and you will see that it is an excellent source for some of your questions you may have.
www.masportaviator.com
If I can help you with any questions feel free to e-mail me.
Good luck
Glenn
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