2002 Honda BF200A shuts off as soon as we increase throttle

I have a 2002 Honda BF200A. I replaced all fuel filters: Low pressure, high pressure, insulator in fuel pump, made sure the float body was clean. Installed all new "o" rings and gaskets and new plugs. Checked for air leaks. and even purchased a diagnostic kit and have no codes. Removed fuel line going into gas tank and screen is clear. Clean air screen on top of motor. and cleaned IAC.

Problem: the motor starts and sounds like its runing good for about 2 seconds then it goes into a real ruff idle it will stay running at this ruff idle. As soon as we give it any throttle at all the shuts down. When its running it seams to be running rich. Thanks

Have you checked compression, sounds like it may have jumped a tooth or two on the camshaft timing

Did the motor run like that before you did the work on it?

Not sure about skipping a tooth - haven't heard of one of these engines jumping a tooth on the cam on it's own, but Ian has a lot more experience than I have. Certainly check compression as Ian suggested. Use topped off or fresh batteries, all plugs removed, throttle wide open, kill switch activated, crank for at least 5 seconds for each cylinder test. Given it's a 2002, compression in the 180 to 200 range would be good as long as there is no more than a 10% difference between the high and low compression readings.

Couple of quick checks...

Make sure that the vacuum tube on the IAB diaphragm has been reconnected. It's easy to forget to reconnect it after you've changed the HP filter. Don't ask why I know that.

Make sure there are no fuel leaks - around the cover to the HP filter, the VST around the connections to the LP fuel pump, LP filter and the onboard fuel/water separator.

Next, I would get a portable fuel tank with fresh fuel and run a fuel hose directly to the LP fuel filter and try to start her up. If it starts, and runs fine, then you know you either have an obstruction in the fuel line, or a serious air leak.

If that doesn't fix the problem, run a clear plastic hose (the same ID as your fuel lines) from the LP fuel pump to the top of the VST as shown in the link below. Start her up and look for air bubbles.
https://www.boats.net/catalog/honda...a2-la-vin-baej-1000001-to-baej-1099999/piping

If not, I would pull the VST again and check float valve and float level and make sure that the passages in the VST are all clear.

If all that checks out, come back at us.

Running rich is a sign that the screen under the fuel pressure regulator is clogged. It'll cause excessive fuel pressure by not allowing the excess fuel to flow back into the VST. You can pull the plugs to see if you are running rich but if it hasn't done it for very long the plugs may not show it. I ordered this adapter https://www.amazon.com/gp/product/B008213NSA/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1 from Amazon to be able to permanently mount a fuel pressure gauge. If your fuel pressure is high or low this would show. Your problem points to high fuel pressure due to a restriction in the return line or screen. Of course it could still be an assortment of other things but you have to start eliminating possibilities.

FYI - fuel pressure should be between 41 and 49 psi at idle.