Thread: Which is the culprit?

This may be way out there is it going into limp mode idles fine but will not get above 2500 rpm`s. Check fuel lines first and see if you have an onboard filter on the engine. It could be your plugs are getting bad plugs will show up more when the engine is pulling harder causing missing, versus ideling. Could be water in the fuel system

here is another thing you can try and I have seen this before also on a friends boat !!!!

https://www.youtube.com/watch?v=IPsqPnFkhAg

Vent on tank open?

It should be fairly easy to figure out. Since it ran good with the other tank & fuel line the culprit has to be one of those 2 things and I'll add it could be the gas too I guess.
1st test I would make is swap out the fuel lines. If that doesn't do it, I'd swap the lines back.
2nd is I would swap out the gas tank. One thing I didn't see mentioned is most of those portable tanks have pick up lines that go from the tank fitting to the bottom of the tank. Those lines have a filter attached to the end of that line on the inside the tank. That filter could be blocked if there is something (crud) inside the tank.
3rd would have to be the gas.
Those are the only variable that changed to make the motor run good again.
Good luck with it.

put zip ties on hoses at /near all clamps . Bought a new hose with bulb at walmart that needed this to run smooth .Worth a try ,cheap also .