Hello!

An explosion is not likely, but engine damage could possibly result if an attempt is made to start the engine. A large quantity of fuel such as you describe will travel down therough the intake manifold, and enter whatever cylinders have intake valves open at that time. If the engine is cranked over with liquid in the cylinders, it could hydrolock: liquid will not compress like air does, so when the piston comes up in whatever cylinder may have liquid in it, it is like striking a solid object. Mechanical damage to the head, valves, piston, or connecting rod could result.

My suggestion would be to remove the spark plugs in the engine, and then making sure the ignition is turned off to prevent any accidental sparks turn the engine over by hand a few revolutions to force any liquid gasoline that is trapped in the cylinders out through the spark plug holes. You will probably find that a few of the plugs are fuel fouled and need to be dried anyway...

Next, as you suspect in your posting, any liquid fuel that enters the cylinders will tend to seep past the rings over time and end up in the engine oil, so changing the engine oil before starting the engine is a prudent thing to do.

Then, reinstall the plugs and the engine should start normally with no adverse effects.

I hope this is helpful; if so, please click my accept button! Thanks!