I have a beta 722 that I am installing in my Bayfield 32. The bottom of the fuel tank is about 3 feet below the fuel pump inlet on the engine. The instructions that came with the engine say to route the return line in a loop where the bottom of the loop is at the same level as the bottom of the fuel tank. I assume this is to attempt to prevent the HP fuel pump from draining it's prime back to the tank. Could I achieve the same thing by returning the fuel to the tank via a second fuel pickup/dip tube fitting rather than using the loop. I believe the dip tube would achieve the same effect as it would prevent air from entering the return line (and thus prevent draining) when the engine is stopped. Adding the loop in my installation is a little clumsy as there is no simple way to fasten the loop in place without causing future service problems.
Another question: I've had the engine since 2011 and am just now getting to the final installation. (Other refit issues with the boat delayed the engine install.) Are there any special considerations I should address with the first start-up for an engine that has sat for so long?
Finally, do you think I'll need an additional electric fuel lift pump for this installation? If so, can you recommend one and how to wire it? I assume I'd want it on when the engine panel key is switched on.
You are not the first (or the last) to take longer than initially expected to complete your boat project. I suggest that you crank the engine over with oil in it and with the stop button depressed for two periods of 10 seconds each. This will allow the oil pump to push oil to the vital parts of the engine for lubrication.
As far as the fuel supply and return are concerned, from your description the simple way to fix all your concerns is as follows;
1) install a low pressure (1.5 to 2 PSI) 12V electric fuel pump and wire this into the ignition system. Connect the positive to the AC terminal at the back of the ignition switch so that it only works with the ignition on. There is a yellow wire in the extension harness that run from the engine to the panel which is not used so this is a good candidate to get the pump power from the panel to the pump. We do have a low pressure electric pump in stock if you cant find one locally.
2) Work a loop in the return line at the back of the engine to stop any drain down. This only needs to be about 8 to 12" to work in this instance.
We installed an electric fuel pump on Beta advice, because the fuel level, when nearly empty is about 3 ft below the engine. The pump runs on a manual switch with the choices between "off" "run when engine on" and "always on"
We find that we do not need the pump to run the engine. Switch is normally OFF.
We find the pump great when changing oil filters or bleeding the fuel system. Just run for a few minutes with the fuel bleed discharge open (we have a valve on ours)
We did not install the loop in the return line that Beta recommends. Our fuel return runs in a dip tube to the bottom of the tank (recommended by a diesel mechanic for our first engine, to avoid foaming in the tank.) We have never seen any sign of the "drain-down" Beta mentions, probably because of the reason you cite, no air can get back up
