I've been chasing an oil leak this year that seems to keep getting worse. I had a mechanic friend over and his best guess is lots of small leaks from lots of small places.... Frustrating though it was to not find one spot to start with, we attacked a bunch of places that seemed to be leaking or seemed like they could start leaking. Tightened the oil pan bolts, removed and sealed the oil galley plugs, but probably the biggest one was removing and replacing the intake manifold gaskets. Since then, things have not been running like they should be.

The symptom: boat runs fine at idle and in neutral through the whole range of RPMs. In the water it runs perfectly up to 2000rpms and then it begins to backfire through the carb (I assume this is whats happening... it POPs and smoke comes out carb.) This only happens when it is in gear but (oddly) it seems to happen worse in forward than in reverse (I suspect this is only because it has reduced load on the engine when in reverse, the tranny seems fine?)

I've got the engine timed to 34degrees @ 3200RPMs. I've advanced and retarded this and the backfire remains always around 2000rpms. It seems to start, idle, and rev (in neutral) best at ~34degrees.

We sprayed carb cleaner around the carb gaskets and intake to head surfaces to check for vaccuum leak but nothing was apparent.

Two things that my mechanic friend noticed when we reassembled everything was that the advance mechanism in the distributor seemed really loose/old. The entire rotor wobbled around far more than what he thought was normal. I've already ordered a new distributor.

The other thing was that he didn't think my fuel pump was putting out enough flow. I have an electric in-line fuel pump and it seems to put out the 6-7psi required but (and we haven't tried with the engine running) it doesn't seem to flow very much. Could fuel starvation cause my issue? I've run out of gas before and it never backfired.... just died or experienced surging. I'm thinking the fuel pump is (hopefully) fine... but... anyone recommend a good marine in-line fuel pump? Does it have to be marine?

For reference -- it's a 454 with an Edelbrock intake and carb.