Originally Posted by
jeffie8696
Surging at WOT can be a glow plug issue
It can also be an undersized fuel line. It collapses under suction, engine leans out, suction reduces, line opens up, engine goes rich, suction increases, then line collapses again. It has happened to me before. One time the line wasn't so much undersized as it was a very thin wall. It was an unusual sized line that came with the ARF fuel tank.