Very common to see ignition problems, they are repairable although not always "cheep". So I'd pull all the spark plugs, stick 'em back in the plug wire boots, ground the bodies of the plugs to the block or metal cowling, and crank-over the engine. Hopefully you'll have a fat, bluish-white spark off each plug, if not you'll know where to concentrate your efforts.
Also take a compression check before you get too deep and spend a lot of money on a motor that is internally shot. If you loosen the rear cowling support, such that the lower cowling "pan" can drop down, you can get a flexible-hose-type compression gage on #4 cylinder. If you don't have a gage, they are inexpensive at Sears, etc or you could rent one from Autozone for "free", just a full-price deposit which is refunded when you return the tool. Can't beat that!
If you have spark and good compression, count your lucky stars! Probably fuel system issues as suggested already. A good minimum service would be to rebuild the fuel pump(s) with inexpensive diaphragm kit(s). In the bottom of each carb is a brass plug with 7/16" head. This is the main jet plug and it has a small gasket ring on it.
Pull the top main jet plug, hook up fuel to the motor, and pump fuel thru the carb. It should flush out the main jet hole, and hopefully comes out clean. If it's full of gunk or nothing comes out, you'll want to take the carb apart for servicing. Reinstall the plug/gasket and flush the bottom carb in a similar manner.
With spark, compression, and hopefully fuel, you'd be ready to attempt to run the motor. Put the lower end in a water barrel or use flushing muffs. Pump the bulb up hard, give the controls some fast idle in Neutral, and choke while cranking the engine/hold choke in until it starts.
After you get it running, be sure to replace the impeller before taking it on an outing. Nothing like burning up your powerhead the first time you take it out, to ruin your day! A $20 impeller is excellent insurance.
Just a brief overview, there is a section off of the main forum page on "how to awaken a sleeping motor". Lots of excellent tips there for the studying.
G'luck & let us know how it goes...........ed
