oil and fuel mixed

what does it mean if my motor oil is mixed with fuel on my rebuilt y block??

 

maybe Some sparkplug's is not working?

 

Does the engine start and run fine? If it does check fuel pump diaphragm for possible leaks. If not look and see if carb needle and seat are stuck and allowing fuel to run into engine when the engine is shut off

 

do an oil change before you wash your bearings!

 

In addition to the above suggestions; a slight leak in a carb needle & seat, combined with an electric full pump that is not being turned off when the engine isn't running, can add a LOT of fuel to the oil over time.

........ and cylinder walls. +1 on the oil change.

 

the engine starts but turns off after 30 seconds im guessing the timing is off...i just did the oil change

 

leaking mechanical fuel pump., or an electric pump pushing fuel past the needle seat.or leaking of carb down the manifold

and as said, dont run it with fuel deluted oil..you'll be sorry

 

Magic... just kidding I vote leaky fuel pump diaphragm

 

ok. the carb was leaking i fixed that, and did the oil change. now gotta set the timing right...

 

The first thing you need to do is get that oil out of that engine before you need to rebuild it again ! Gas from the carb is draining down when the engine isn't running and washing the cylinder walls down and cleaning all the oil film you have on every part you have in that engine !
First it is probably your carb so a simple carb rebuild should fix the problem . When you change your oil add a container of Lucas engine break in to your oil . That will help coat all the parts as you start your engine . You can buy that in Advance Auto and any place that carries Lucas products . You also need to use the proper oil for flat tap cam . DON'T use the thin synthetic oils either ! Use a good 10-30 or 10-40 oil and make sure you add the additives with ZDDP OR oils that have them in it . Not many in the stores where you buy oil but easy to get and don't use Diesel oil either !
Amsoil , Brad Penn , Comp Cam , Joe Gibbs , Mobil 1 original are a few that has what you need .
If you use good oils and a good filter and not FRAM and the other junk parts store sell , the engine will last a long time ! I use either a K&N or WIX racing oil filters on my engines ! They are the best ones to buy out there !
Keep us posted on how your engine makes out !

Retro Jim

 

thanks lots for your help. my engine hasnt been driven on the road yet. it should still be fine right?