Engine surges and runs out of gas
 

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 ????

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

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

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.

What he said.

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.

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.

Anti-siphon valve?
 

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

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.

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

As inexpensive as they are, put a new primer bulb on it. I've had several go bad over the years. Had problems with upstream and downstream ends.

Now that you know the engine runs fine on an external tank, identifying the core issue is a pretty straightforward process of elimination. An easy way to test if the starvation is caused by a blocked fuel tank vent is to just remove the internal gas tank fill cap while underway, and see if it "solves" the issue. If no change, maybe Uboo's suggestion of a new bulb would be worth trying. I know you said you cleaned the tank out really well not long ago, but I think it's still possible that something is getting clogged in the pickup tube (probably because my cousin had the same exact problems and symptoms not long ago, and he found algae clogging up the mesh on the pickup tube). He actually took OFF the mesh from the pickup tube (after cleaning the tank and refilling with fresh fuel), as he has a clear bowl Racor water separator/filter, figuring that it would be better to capture crud in the bowl where you can see it, rather than trapping it invisibly inside the tank.

When I ran it off the internal tank I did open the fuel cap and it didn't do anything. The bulb is new or at least new 6 months ago but easy to swap out. When I get back home I'm going to inspect the pickup in the tank and work my way back. It's either in the tank, on the pickup or the filter so could be easy to fix.

I am going with the comment that maybe your pick up screen is plugged. Is this a older tank that was empty during your rebuild. Try blowing air through you fuel line back to the tank. If it fixes it you need to clean out your tank.

Yes I think it's in the tank. What sucks is that I have close to 60 gallons in there to fool with

Jorge- with what you have already eliminated, my leading theory is the tank like the piece of paper or part number tag on my dad’s Pontiac tank- it was intermittent. But easier things first. Replace the fuel bulb with an OEM bulb, not an aftermarket one like a mechanic ripped off mine one time, exclaiming get rid of this piece of crap

Did you inspect the fuel lines yet?

strick

Could it be that a lot of crud was loosened up and didn't come out. Maybe clogging a screen in the pickup (which I don't see what its purpose is) , or clogging up the fuel filter, which I assume is ahead of the bulb.

Some pickups have a check valve in the elbow on top of the tank - they can get screwed up easily.

Got back from New York today visiting my daughter. Plan is to work on it tomorrow afternoon.

I run 3/8 alum pipe with a v notch at the bottom.

Sometimes the racor housing can corrode and have pin holes
as well, but probably not his issue.

How old is your fuel line? Some fuel lines have an internal liner that has been known to delaminate and cause a blockage!

Also, you mentioned recently cleaning the tank. Did you use any sealant on the sending unit gasket? Years ago when I was young and dumb, I used RTV/ silicone, which is not resistant to gasoline, and a bunch of it got into the tank and plugged the fuel line, causing exactly what you’re seeing! I wouldn’t use any sealant but No. 2 Permatex, the type that does not harden.