"...even though i have fuel turned off while trying to get it working..."

While it may not be the source of your troubles, it's worth noting that the Limited Fuel option only determines whether you can spawn a boat with full fuel tanks or not. Fuel is still needed for engines to run even with that setting on.

If you grab a digital display from the display category, and connect its green logic node to a logic node for your fuel level (Standard tanks have a liquid level output. Custom tanks will need a fuel level sensor pointing inside) you can look at it and see how much fuel you have.

It could be overheating, but that's fairly dramatic. The engine speeds up a lot before bursting into flames.