Bob Tankersley
Recruit
- Joined
- Mar 24, 2019
- Messages
- 4
The recurring similarity of reported events of loosing engine power on Volvo Pinta boats after normal operation for 10 to 20 minutes could be correlated to the absence of adequate venting of the fuel tank. The symptom of engine running normally for a short time and subsequently stumbles and dying fundamentally indicates fuel starvation.
As fuel is drawn from the tank the volume (space) above the liquid is increased and without venting, the static air pressure is proportionally lowered, forming a partial vacuum. The fuel tank must be vented in order to maintain normal atmospheric pressure on the liquid surface. The reported symptoms reflect a pattern of engine restart and run normally after a short interval supports this hypothesis ,because the time interval has allowed limited venting to restore atmospheric pressure and allow the low pressure (lift) pump bring fuel up from the tank.
The fuel filler cap is the only route to vent atmospheric pressure into the tank, which cap it has an internal plastic “SURGE PLUG” that is intended to prevent fuel from spilling out on the side of the boat when making sharp turns. The surge plug can become wedged in the cap and remain closed, preventing air from freely entering the fuel tank. The reported varying time intervals between stalling events is explained based on the fuel level in the tank. The time interval between the stall is predicated on the fuel level at the time. The time interval would be shortened when the fuel was almost full, because the air space above the liquid would be small and without adequate venting a partial vacuum would form sooner than if the tank was nearer empty
As fuel is drawn from the tank the volume (space) above the liquid is increased and without venting, the static air pressure is proportionally lowered, forming a partial vacuum. The fuel tank must be vented in order to maintain normal atmospheric pressure on the liquid surface. The reported symptoms reflect a pattern of engine restart and run normally after a short interval supports this hypothesis ,because the time interval has allowed limited venting to restore atmospheric pressure and allow the low pressure (lift) pump bring fuel up from the tank.
The fuel filler cap is the only route to vent atmospheric pressure into the tank, which cap it has an internal plastic “SURGE PLUG” that is intended to prevent fuel from spilling out on the side of the boat when making sharp turns. The surge plug can become wedged in the cap and remain closed, preventing air from freely entering the fuel tank. The reported varying time intervals between stalling events is explained based on the fuel level in the tank. The time interval between the stall is predicated on the fuel level at the time. The time interval would be shortened when the fuel was almost full, because the air space above the liquid would be small and without adequate venting a partial vacuum would form sooner than if the tank was nearer empty