Need some help here

[BobbyD]

Just built 39" boat, 3674 bl motor, stinger strut, 1.73 x1.6 prop..
Issue is, just cavetate and wont get going.

Ideas ??

[Alpha]

Hi BobbyD What is your complete setup? If ESC? Battery?

[BobbyD]

Esc 120 amp, batt, 3s 5200ma

[Alpha]

When you say your prop cavitates and "won't get going", have you checked that the prop is firmly connected to the shaft, and isn't just free spinning? Also, what is the prop's specs? Is it matched to that motor/kv and to that boat size?

Has the boat run fine before, but is now not working? Or is this an entirely new setup? I read that you just built the boat, but I'm asking about the power system itself (motor/shaft/prop/ESC/battery). Has that power system proven to run fine before?

[BobbyD]

Its same motor/prop combo used in the sonicwake 36"
it never ran before, i just built it.
And no prop/shaft is not slipping.
Prop is 1.7 x1.6
Motor, prop, shaft, all is new

[mr.frankenjet]

can you lower the strut a but ? Move the cg back a little ?

[BobbyD]

Mr. Frankenjet,
Going to try relocate batt back a bit next time out....

[mr.frankenjet]

for tuning, strut (depth and angle),prop(dia, blade count,balance and pitch),cg, trim tab settings all need to be set to make boats perform best and handle well,

surface drives like this are fast as less drag is produced by lifting much of the drive hardware out of the water, the design is to have 1/2 or so of the prop out of the water so they tend to cavitate a bit more before they catch. good luck.