Suzuki 2012 d40 surges

[Neilll]

My 2012 d40 suzuki surges when I accelerate in neutral but out in the lake it seems to run ok but about 25% slower at full throttle. Ran good last fall before putting away only thing I did was put on new 12 gallon tank filled with new gas and used old adapter for tank from previous tank. Any ideas.

[Moonlighter]

It has caught us all out sometime ....... But I have to ask: Have you opened the breather vent on the new tank?

Accelerating in neutral will result in the over-rev protection cutting in at about 2000rpm, so that would likely explain the surging you described.

Also possibly think about a new connector, old one could be letting air in?

Have you checked fuel lines lately? Old fuel lines can deteriorate internally and partially block flow, without any external signs.

Is this motor a DF 4 stroke one or a 2 stroke DT?

Especially for the fuel injected 4 strokes, a separate Racor style water separating fuel filter is essential. They do not like dirty fuel at all!! Not a bad idea on the 2 strokes either.

[Neilll]

suzuki surges

Yes the air breather is open, I installed the old adapter with teflon tape I will get a new one. It is a 2012 4 stroke. I will check or replace the gas filter. Anyone have any idea why I seem to have less power?

[Solarman]

Grant/ moonlighter is right on old connector, and filters. Even for 2 strokes, lol.

When surging as you mention, does pumping bulb do any good? Or, is any air in fuel filter on side of motor when this is happening?

Post back when able.

[Neilll]

Pumping does not change anything and yes you can see air in the filter.

[Moonlighter]

Then you have an air leak in the fuel lines somewhere. Find that and you probably solve your problems. Check all fuel lines, every connection, and the first thing is to change that connector on the engine to a new OEM one.