Engine blow by

My 1975 350 OMC has a lot of blowby, I have ordered a new DUI to replace the GM delco HEI which whoever installed did a horrible job, it leaks oil all around the intake. It is coming out the dipstick in small amounts as well. Performed a compression check today and had 180-190 degrees on all cylinders and the engine runs well.   I bought it set up with 1 line from each valve cover joined together with a chrome item with a vent, it emits small amounts of smoke when idling. I do not know if it is a PCV valve or not. I have no where to connect to my flame arrestor unless I modify it. How should I vent the crankcase on this old little darling? That has to be the problem with compression that good. Previous owner (they are always good to blame) did not do anything right that I have seen yet so I know he probably ran these vent lines together from the valve covers. Bilge is full of oily water after an 2 to 3 hours of running now.

Where do you get vacuum on this old motor?

Jbradford wrote: By the way I have a new to me Rochester Marine Quadrajet Carb, the boat did not have a marine carb before.

Interesting.
if you are running a quadraflush i assume you have an adapter (and) wedge. Many times these (spacers) are fitted with ports. Not so? Thats OK, we can get around it. Pretty sure there is a vac plug in the plenum if needed.

Just for giggles do me a favor. Next time your aboard, fire it up and at idle, pull the oil cap and rest a dollar bill or other paper over the hole and see if the bill pumps.
I expect not but hate to overrule a broken ring none the less.
> Dumb questions:>
oil weight?
How much oil is in it?
Gotta start there.

Tried with a dollar bill and it just basically lays there at idle.   I took a pic of my carb and I know it is not the best but could not get a good angle. Where fuel comes In there is a barb that has rubber piece on it to seal off that below fuel entrance, the one above is going to hook to my new marine fuel pump I think is correct.

On the picture above, that port with the black rubber cap on it (just below the fuel inlet) is a good port for your PCV hose. Make sure to use a PCV valve -- don't just hook-up a straight hose from the valve cover port or you'll have a monster vacuum leak.

If you choose to not use a PCV valve, then you can run hoses from each valve cover up to the flame arrestor.

Also, don't over-fill the crankcase with oil. I've seen situations where an over-filled crankcase has pumped oil out from various locations.

JQ

Jbradford wrote: That will work Thank you.   The barb above fuel inlet is where I ran my new marine fuel pump overflow to, I assume that is correct?

Some marine carbs have a barb/port for the fuel pump diaphram rupture safety tube. Did the carb have the safety tube hooked up originally? If there is any doubt, put a rubber cap on the barb/port and run the fuel pump tube up to the flame arrestor.

JQ