My 90 honda civic has gas in motor.What causes that'?

My 90 honda civic has gas in motor. What causes that'?

Please be more specific.
gas in motor as in gasoline mixed with engine oil? If so you have a stuck open fuel injector, fuel pressure regulator is bad or bad FPR vacuum hose. Even a bad sensor will cause the ecu to dump excess fuel in the mix if left alone.Eventually your engine oil will smell like gasoline and will self destroy due to the change in oil viscosity…

if its not the engine oil but the engine bay then there's a fuel leak somewhere. You need to stop the car and find it NOW! Or else you take the risk of appearing on the local news as " this just new… A car on fire… Hopefully the owner is ok."

IF no fuel leaks(as in visible wet areas) then inspect the charcoal canister vapors line and inspect it.It could be abroken hose or that the gasses coming from tank are leaking out the evap canister due to a defective caharcoal canister purge vale.Again fix this inmediately.
gl