Dtwo1946
Active Member
Good afternoon Gents.
My Suzuki DF70 will always start first turn then run perfectly for up to an hour before running down and stopping. Pumping the bulb gets it going again for up to ten minutes, still starting first turn, then it does it again. This can be done repeatedly. Coming back from a recent trip my mate sat in the stern and pumped the bulb when the engine started to falter. Every time, the engine picked up again for five minutes or so before needing the bulb pumped again. We did this for about four-five miles. This motor is running perfectly as long as it's got fuel.
The high pressure fuel pump and both filters were replaced in November and there are no fuel line leaks. Air is not getting into the lines or the system anywhere. I replaced the mechanical low pressure pump this weekend and the problem persists.
This problem is recent and coincides with hot weather. Research shows that this is not unknown. Apparently It can be caused by temperature related fuel vapourisation in the lines forcing the fuel back towards the tank or simple vapour locks. The new mechanical low pressure fuel pump's check valves (non return) are OK so the problem should not be between this and the High pressure pump. Unwisely, I think, this is a short hose across the top of the motor. I've re-routed it so it follows the side of the motor next to the inlet mnanifold. It should run cooler. I took the thermostat out to get more cooling water around the motor but 'no joy'. I've fitted a non-return valve in the line near the union of the fuel tank to the motor to try and stop the fuel flow reversing but this has also failed. After the motor failed when testing all of these potential solutions on muffs it still starts first turn of the key after the bulb is pumped.
I can't see that it's anything other than fuel starvation and my next step is to fit an inline electric fuel pump near the tank to simulate pumping the bulb before I give in and tow it to the Suzuki dealer. This has worked for a number of people in the past and was actually recommended by Suzuki. Problem is there's no information I can find about what Psi this pump should deliver. I don't want to overstress the lines and unions leading to dangerous fuel leaks in the engine. The options seem to be 1.5 to 4, 4 to 7 or 7 to 11 Psi.
Please, can anybody advise me on a safe maximum Psi level for this pump? I need to avoid it being too low as that will mean buying a second pump and a good one is not cheap!
My Suzuki DF70 will always start first turn then run perfectly for up to an hour before running down and stopping. Pumping the bulb gets it going again for up to ten minutes, still starting first turn, then it does it again. This can be done repeatedly. Coming back from a recent trip my mate sat in the stern and pumped the bulb when the engine started to falter. Every time, the engine picked up again for five minutes or so before needing the bulb pumped again. We did this for about four-five miles. This motor is running perfectly as long as it's got fuel.
The high pressure fuel pump and both filters were replaced in November and there are no fuel line leaks. Air is not getting into the lines or the system anywhere. I replaced the mechanical low pressure pump this weekend and the problem persists.
This problem is recent and coincides with hot weather. Research shows that this is not unknown. Apparently It can be caused by temperature related fuel vapourisation in the lines forcing the fuel back towards the tank or simple vapour locks. The new mechanical low pressure fuel pump's check valves (non return) are OK so the problem should not be between this and the High pressure pump. Unwisely, I think, this is a short hose across the top of the motor. I've re-routed it so it follows the side of the motor next to the inlet mnanifold. It should run cooler. I took the thermostat out to get more cooling water around the motor but 'no joy'. I've fitted a non-return valve in the line near the union of the fuel tank to the motor to try and stop the fuel flow reversing but this has also failed. After the motor failed when testing all of these potential solutions on muffs it still starts first turn of the key after the bulb is pumped.
I can't see that it's anything other than fuel starvation and my next step is to fit an inline electric fuel pump near the tank to simulate pumping the bulb before I give in and tow it to the Suzuki dealer. This has worked for a number of people in the past and was actually recommended by Suzuki. Problem is there's no information I can find about what Psi this pump should deliver. I don't want to overstress the lines and unions leading to dangerous fuel leaks in the engine. The options seem to be 1.5 to 4, 4 to 7 or 7 to 11 Psi.
Please, can anybody advise me on a safe maximum Psi level for this pump? I need to avoid it being too low as that will mean buying a second pump and a good one is not cheap!
