Fuel flow restriction on Gambler 2100

[jmo]

Good Morning!

Has anyone experienced problems with the gambler fuel fill vent? My 2002 2100 Merc 250XB runs great up to "full speed" but on long runs it will shut down to an idle (but doesn't die). After 3-5 seconds I can apply throttle and it will run with no issue. I haven't experienced any performance issues at mid RPM range 4500-5500. The dealer recently serviced entire fuel system from tank back, new lines, clean flow injector, all new lines under cowl, VST clean, rebuilt pulse fuel pump, new filter, etc. So I don't think this is engine related. I'm thinking vent or fuel pickup restricting fuel flow?...and the issue was there prior to this work....was hoping replacing the old lines would fix it. Engine received a clean bill of health with regard to compression and leak down so it is healthy.

Please advise if you have any thoughts on how to check or what to check?

Thanks..Justin

[low slung cruiser]

sounds like fuel line needs replacing...
ive seen 2 different boats do this...
need replace from tank to motor...may need to rebuild Fuel pump on motor...

[jmo]

It is all new fuel line from tank to motor and all lines under cowling including pulse fuel pump. No change...

[TNbasskicker]

Maybe something built a nest in your vent line to the tank. A spider or some kinds of bees are bad around here to put mud in the lines and stop them up. I even have to put a stick in key hole on my lawn mower to keep them from filling it up with mud and plants. There're called leaf cutter bees and will build in any kind of small hole. Other than line problems could it be kicking into guardian mode some how where the computer slows you down ? Does your alarm beep sound when you turn the key on ?

[Gamblerman65]

I have seen the anti siphon cause a lot of different fuel flow issues..

[Gamblinman]

I have seen the anti siphon cause a lot of different fuel flow issues..

Ding ding ding ding...we have a winner.

I would be very careful about running at full throttle and losing fuel. I have a 300X I bought and hanging on stand that was experiencing the same issues...it leaned out. Its fixable, but he pushed the limit and paid the price.

[jmo]

Is the anti siphon valve in the tank or in the 90 degree fitting on top of tank? They replaced to 90 so I’m guessing it’s in the tank. I’ve looked at the fuel cap it doesn’t appear there’s a true vent line it appears there is a seal on the cap that allows air in the filler neck as required. It’s happened 2 times. Once before service work and this weekend. That’s why I want to get opinions on a fix....before it gets costly. Is there a method to test to determine if it’s the anti siphon valve?

[Gamblinman]

Anti-siphon valve IS the 90° fitting on top of tank. There should be 2 hoses that run from gas spout to tank. smaller one is vent, larger one is tank fill.

At this point, I think I would run on a remote tank and see if you can duplicate the issue, That would at least narrow down the possible trouble spots.

[jmo]

I will try a separate tank and see how it goes. Thanks for the input guys!