Carefull when adding electric pumps.
If the MH did not have a factory installed pump (some that were factory installed as well) there could be a HUGE safety concern as the fuel flow is only controlled by the float in the carb.
If the pump is at the engine end it is not as much of a problem as the fuel path is visible, but if the pump is mounted near the tank you could have big problems.
Given the following.
Older MH that is poor starting and fuel starved under power
Runs ok when idle after it finally starts up.
New fuel filter and hose from engine mounted pump to carb.
Older MH, check valves in engine fuel pump may not seat real well and unit not able to pull good vacuum.
(it must have been ok when new...)
Electric pump added at engine end
Pump runs for awhile then stops, pulls fuel from tank and charges the system, engine starts like new and power is restored.
Electric pump added near tank
Pump runs for awhile fast and charges the system
Engine runs fine and power is restored
MH does not seem to get the same mileage as before?
Funny smell of gas when we stop?
First off, if an electric fuel pump is added anywhere in the system it needs to have a safety system, simply put, it needs to only be running when the engine is running or starting (safety bypassed), this is simple as an oil pressure switch to countrol the pump, when oil pressure is present then the pump can function. During STARTING this is bypassed via power from the starter relay, this allows the pump to charge the carb in the seconds that the engine is cranking, then once oil pressure is present it can resume.
If there is an accident, broken line or other issue that causes the engine to stop the pump will stop so there is not a constant fuel bath from the leak.
Loss of fuel?
If the MH is older there is likely small hairline cracks in the fuel line, these allow air into the line which reduces the ability of the engine mounted pump to pull the fuel up under the slow cranking speeds and also allows the fuel to drain back into the tank.
Adding a pressure to the line via the new electric pump mounted at the tank gets the fuel to the engine but also sprays or seeps the fuel out of the above holes and causes loss of fuel and coating things with the gas, now with fuel and air all one needs is a spark to light it up, and if there is no oil pressure interlock the engine will die when the fuel line melts, but the pump will continue to feed the fire until one turns off the key, but since the fire is under the MH and it is rolling down the road turning off the key is not the usual first action.
So, fix it correctly as the factory intended.
REPLACE the fuel line end to end (all rubber and non-metal parts).
Replace the fuel pump, filter and all clamps.