Engine surges and runs out of gas

[jorgeinmiami]

Went out today by myself to try out the new Garmin and it works great and reads at a fast speed.

Now the engine is still doing the same thing. Starts and idles fine, get up on a plane and runs great.
A minute or two the engines bending to surge and runs down like it's out of gas. Checked the bulb and it was flat. Tried to pump it but being alone it's tough to do. I recently changed the favor filter and the filter in the VST. I'm running fresh Rec90 and added ring free plus so I don't think the gas is the issue.

Plan on getting a external gas tank and running it off there to see what happens.

Any other ideas ????

[Kwaugh5p]

If the bulb is flat sounds like it isn’t getting fuel. Is your vent working. Is there a restriction somewhere in the fuel line fuel filter is not plugged

[jorgeinmiami]

Tomorrow I'm going to start at the tank and work my way back to the engine checking to make sure all the hose clamps are good and no kinks in the hose. I didn't think of the vent so I'll look at that also. It probably something simple but takes time to go through it . I pretty sure it's not the tank since I cleaned it out pretty well before I reinstalled it. Glad I haven't sealed the tank lid yet

[bmajvi]

Does the pickup tube have a mesh screen over the intake? Crud floating around in the tank can get sucked into the pickup and cause that starvation issue. I think trying the external tank is the right next move. Good luck.

[Fr. Frank]

Originally Posted by bmajvi

...I think trying the external tank is the right next move. Good luck.

What he said.

[jorgeinmiami]

Went to the boat today and the 1st place I looked was the hose to the vent . Sure enough it was kinked. Removed the straight line vent the goes thru the hull and will replace it with a 90° angle one tomorrow. Hopefully that takes care of that.

[jorgeinmiami]

Sealed out the vent to a 90° fitting and ran the boat ....still surging. Went to a external tank and it works great. I'm done in islamorada this weekend so I'm going to get a 6 gallon poly tank till I get back home.

[Capt Terry]

Jorge-
After I put a Racor filter and vacuum gage on my ETEC I found I was at or near the vacuum limit even with a brand new fuel filter. I had replaced the fuel tank a few years before and had used the original 90 degree elbow on the top of the tank. I discovered it was also an anti-siphon valve. So I drilled out the elbow to remove the ball and my vacuum dropped in half. I routed the fuel line with an increase in elevation so it would not siphon if there was a downstream leak. I did not experience your problem, but thought it was worth mentioning. Good luck

[jorgeinmiami]

So I'm back from Islamorada after to nice days down there. The boat ran well on the 6 gallon tank.
So things I noticed .....the 6 gallons ran out faster than I expected...wonder how much I'm burning?

I pretty sure I need to raise the engine up 1 hole. I'm only getting 4900 rpms at full throttle, and maybe a different prop. I'm going to get the cables etc...to connect the engine to the Garmin and that should give me some burn numbers. I don't like the way the lower clunks when shifting into gear. The transducer works great but it sprays up so I need a spary guard.

Off to Nashville this week for work so I get to it next week.

[Beaver]

Did you recently fill the fuel tank to overflowing? Sometimes you can get fuel pushed into the breather hose. If there is any sort of dip in the hose, the dip will fill with fuel and keep air from passing. Try pulling up any slack on your fuel line to take any bow out of the line. You can also try blowing air into the breather hose to force any fuel back into the tank.

Another possibility is that you are using Mecury Quicksilver fuel lines. These lines have a thin liner on the inside of the hose that is affected by Ethonol. The liner will collapse making it impossble for fuel to be drawn through. Think of drinking a chocolate shake through a very thin straw.

How these idea help. Good luck.

Rob