Need Help Getting at Carburetors on Mercury 650 (1970 model)

[scottwoodward]

I've recently acquired a boat with Mercury 650 engine (1970 model, serial 2804270). I'm fairly handy, but new to more in depth repair and maintenance. No experience maintaining outboards. I've been able to start the engine, but she won't run but for more than 10-15 seconds, presumably running on the seafoam I've put into the cylinders. It's starved for air or fuel, or both. Manual choke did nothing to help today.

I'd like to get at the fuel system -- filters and carburetors, but can't seem to figure out the best way to get at them. I tried removing the front plate where the wiring harness attaches and where the distributor wires attach, but could not get the two lower bolts that seem to attach to the lower cowel. Coming in from the left side of the motor (looking from front), looks complicated.

Anyone out there got tips on best method to get at the carburetors? (see photos). You can see in the photos that the choke solenoid is probably toast. It has leaked on to the top carburetor. I've got the original manual, but it doesn't seem to be of any help in figuring out how to best get at the carbs.

 

[Chris1956]

That is a pretty standard Mercury OB configuration. You will need to disconnect the battery, remove the 3 7/16" top cowling support nuts, and disconnect the choke wire.

Now remove the 4 bolts on the rear lower part of the bottom cowl, as well as the two bolts on the top front of the cowling support.

Now remove the top and rear cowling support as a unit. Next unbolt the front cowling support and let it hang on the switchbox wires.

It is a good idea to remove the starter (4 bolts, two cables), as the carb mounting bolts are partially covered by it.

The top carb will wiggle off past the distributor "finger". Don't break the carb plastic connection, as they can be hard to come by.

 

[scottwoodward]

Much appreciated Chris!