1995 Speedster engine shutting each other down!

[renegade250]

Ok, yes I am new to this place, but Hi everyone.
Now for the reason I am here. I have looked but did not find any posts like what mine is doing.
I had one engine rebuilt and has less than 10 hrs on it. The other engine has good compression on it.
BUT.... when i start both in the water and start to plane out they both will die.
Then when I restart them and start to throttle up the non rebuilt engine will die out. Then when I restart that engine(nr) and throttle it up first then the rebuilt one will die out. It is like they are countering each other out.
Can not figure out why!
All connections look and feel good, no corrosion or loose rubbing bare.
Any help would be greatly appreciated!!!!

 

[Dr Honda]

Wow... no idea. If it was electrical... I would think it would shut down as soon as the other engine was started... not after you are throttling up.

I guess I would look for an air leak in the fuel system first. I would also clean the fuel select valves. They can have a leak, or be plugged up. Or better yet... just replace them.