Adding a Primer to your intake can help engine starting problems. Your cheap lawnmower has one, why shouldn’t your airplane? Infact most airplanes do have them. It also depends a bit on what type of carburetor setup you have, but this could work good for most setups.

It’s best to use an injection system that sprays into the intake valve area. When cold it is difficult to get the fuel mist up to the cylinders from a carb mounted under the engine. You need a primer unit (small pump type device), some 1.8″ copper line and then drill/tap into the intake area; probably right in your intake tube/manifold above the head. Preferably you do both sides of the engine. Two cylinder injection will suffice. You will need a small jet screwed into the intake. You can solder up the hole in the fitting that you screwed into the intake. Drill about a #70 or 1/64″ hole thru the solder. This should produce a mist at the intake valve when you push on your primer. Fuel for the primer is taken from a convenient place on the fuel line. Usually about 2 to 3 pushes of the primer is enough to start the engine. Make sure you lock the prime after pushing on it. Otherwise the engine will suck fuel from the primer system and flood itself or run rich.

This all sounds a bit complicated but it really isn’t. This should solve most starting problems.