DF140 fuel leak down

[xchief]

Having problems with my fuel leaking down. I pump the bulb on initial startup. Not always but in many cases, I can take off with no problem. Sometimes the engine stops and I have to pump the bulb again. If I stop to fish, I always have to pump the bulb. Sometimes it run til I get on plane and stops and sometimes I can run full open for miles with no problem until I stop to fish.

I have changed the bulb out, replaced the water separator, replaced the fuel hose from tank to bulb. All clamps are as tight as I can get them.

Have not changed hose from bulb to pump, but I see no leaks nor smell no gas under the top cover.

Could it be a bad fuel pump? How do you check the pump?

Could it be an injector problem?

Any and all help is appreciated.

xchief

[Moonlighter]

Possibly the anti-syphon valve on the tank. Not required, so remove it. You can unscrew it from the tank, punch out the ball spring and seat inside and reinstall it. Or, just replace it with a brass barb of the correct size and thread.

Even if this is not the problem, it is a no-cost item to do and there is no downside.

Also, have you checked the tank vent line? Make sure the line is not kinked somewhere or the vent is not blocked - those mud wasps like to build nests in the end! If you can, take the line off the inside, take the tank cap off amd blow through to make sure the vent line is clear.

My money is on the anti-syphon valve though. We had very similar symptoms on our Striper a while ago, did everything like you did and it didnt work. Eventually did the anti-syphon valve as described above and problem was solved.

[nelbur]

The anti-siphon valve is required in boats in the US. It is a check valve which, if it is working correctly, should prevent fuel from running back into the tank.

DF 140's, mine included, occasionally have a vapor lock problem where the fuel vaporizes in the fuel line and the low pressure pump seems to have problems getting rid of the vapor. The fuel line snakes between the block and the intake manifold. I plan to reroute mine this winter through a cooler location. Suzuki did a fix for folks under warranty, if they were persistent, which consisted of an electric fuel pump and a pressure regulator, to force fuel into the low pressure pump. Suzuki has recently come out with a new low pressure pump which has a V in the part number. I have not heard if the new pump solves the vapor lock problem. Fortunately pumping the primer bulb with the engine idling seems to solve the problem when it occurs.

[Moonlighter]

The anti-siphon valve is required in boats in the US. It is a check valve which, if it is working correctly, should prevent fuel from running back into the tank.

DF 140's, mine included, occasionally have a vapor lock problem where the fuel vaporizes in the fuel line and the low pressure pump seems to have problems getting rid of the vapor. The fuel line snakes between the block and the intake manifold. I plan to reroute mine this winter through a cooler location. Suzuki did a fix for folks under warranty, if they were persistent, which consisted of an electric fuel pump and a pressure regulator, to force fuel into the low pressure pump. Suzuki has recently come out with a new low pressure pump which has a V in the part number. I have not heard if the new pump solves the vapor lock problem. Fortunately pumping the primer bulb with the engine idling seems to solve the problem when it occurs.

Just correcting that: anti-syphon valves in US boats are only required in inboard powered vessels, not outboards, so he doesnt need one. Check the CG regs and I think you will find this spelt out there.

They are known to fail and be a possible cause the types of issues described.

You may be right with the vapour issue being the problem, i have seen reports of that issue and it also makes sense.

But removing the anti-syphon valve as a first step also makes sense. If the Op is really keen, he can always fit a new one in place of the suspect one if removing it solves the problem.

[xchief]

Thanks to ALL for the input. I was at the local dealer yesterday and he told me about the check valve being the possible problem. I bought a new one and will put it on today along with checking the other items mentioned. Will let you all know how it goes.
Again thanks.

[xchief]

Well NO LUCK on the fix. I have replace everything from tank to discharge side of bulb. Mine did not have the check value on the tank but I installed one since I did purchase a new one. Went out and ran it this afternoon. Still have to pump bulb after setting for a while and trying to crank. When I get it running after pumping it up, it might run 100 yards and shut down. Pump it again and it will run wide open for miles or until I stop again. I even took the fuel cap off to see if there was a vacuum problem and still shutting down.

It does not run long enough to have a vapor lock problem. After setting and fishing the engine should be cool. Then again it will run for miles once I get it going, so if heat/vapor lock was an issue, you would think it would stop after getting the engine hot.

To the shop on Tuesday, I guess. Nothing left to check but fuel pump. Anyone ever test a fuel pump??

If there are any more idea's out there, let me know

[michealstich]

My fuel pressure drops like a rock and is zero within the hour. I haven't tracked down why yet because my car always starts instantly and runs strong. When it becomes a problem i will track it down. :cheers: