hi all, 87 crx si, i get about 300 miles or 500 km to a full tank, problem is i think i smell fuel in the exhaust so i think its running rich. Its a stock motor with no addons so i want to know if that mileage is normal. If not what can i do to increase it?

 

That sounds pretty good to me, assuming it has a 10 gallon tank, then thats 30 MPG.

 

To answer your question we would need to know how much you actually fill up with rather than just "a tank". My personal experience is that I have to drive the living snot out of my 87 Si to make it get less than 30mpg. With that said, the most common reasons for our cars to get poor mileage, especially if you suspect an over rich condition, are ...

1) your engine needs an overall tuneup
2) dirty air filter
3) partially blocked and restrictive exhaust system
4) bad O2 sensor
5) bad FPR (fuel pressure regulator) or restricted fuel return line

Inspecting the plugs will give you a general idea but only an emissions sniffer test will tell you for sure.