df140 not going more than 4000rpm

[knightridyer]

i have a suzuki df140 2010 model and it was over-hauled lately and it isnt going more than 4000rpm when on load, and on free boat it only goes up to 5100rpm still inst enough before was getting 6200rpm maximum on load when trimmed.

please advice on theses problem. thank you

[boats.net]

Prop could be be large of pitch, don't know if engine did turn more rpm's before it was rebuilt. Check compression, check fuel pressure, check that all cylinders are firing.