What kind of grass do you have? Bermuda loves reel mowers. Bluegrass, ryes and fescues usually are better cut with a rotary.
90% of "broken" lawn mowers are suffering from bad gas or problems caused by bad gas. Unfortunately, the wonderful ethanol that is being added to our gasoline (for no good reason) is a literal sponge for water. That water causes corrosion in carburetors when the gas isn't drained as part of winterizing. It can happen in the spring with a month's sitting around. If the gasoline you are using isn't stored in a sealed container and less than 2 months old, get some fresh gas. Buy premium as the alcohol degrades octane over time. For example, gas powered string trimmers such as a Stihl brand require 89 octane, not 87 and in a few months 91 is down to 89 easy. Draining the gas out of the old mower and replacing it, using a little carburetor cleaner and some compressed air could return your mower to life. If this doesn't help and the spark plug isn't filthy, and the thing is rattling apart, (and you really want a new mower) maybe it's time to retire it.
First let's hear what kind of grass you have!
Some may never live, but the crazy never die. -HST BOTOC Power!