Fuel pump or carb?

[LSmiley]

I have a 72-74 Mercruiser 140 in an old Intrude tri-hull. It ran like a top when I stopped using it about 8 years ago. I fogged it regularly and kept it drained. I recently started getting it back running.
So far I have:
Replaced the points, condenser & cap, rotor.
Replaced the fuel lines, cleaned the tanks.
New battery.
I am waiting for a timing light but if timing was off I figure it would not start so easily. it fires cold with no cranking. It fires warm easily also.
The coil checks out OK, all electrical has been checked. It actually fired off and ran with only about 10 seconds cranking, after sitting all those years!

It runs a little rough at idle but not bad, accelerates OK but at about 3000-3200 RPM it surges a little and max RPM is about 3400 and rough. The plugs are black sooted and it smells like it is running a little rich. I added an in-line fuel filter just in case I have any latent gunk and it barely has any fuel in it while running.
I am guessing either fuel pump or carb.
Also, my book says 4200-4600 WOT (I assume Wide Open) and I only get a rough 3400+/-, which seems to point at fuel flow to me.
cing parts?
Any suggestions before I start replacing parts?

 

[zx9rstv]

Re: Fuel pump or carb?

The adults only section has a fuel system check list if you have questions about your flow. On a side note. If the boat has been sitting that long, I would highly recommend rebuilding the carb regardless. There has got to be some gunk built up in it at this point and you'd only be doing yourself a favor. As for the fuel pump. Follow the list in this link
http://forums.iboats.com/showthread.php?t=283269

 

[Leaddog]

Re: Fuel pump or carb?

I agree with the carb cleaning, gas evaporates and leaves a waxy tarnish in the carb that restricts flow.

 

[jones01m]

Re: Fuel pump or carb?

I suggest you get your timing and dwell set correctly before going any further.
I haven't been long with the boating forum, but with any engine (boat or car) I always start with these two first.