The Weed Whacker attachment is in the quarters of Captain Ziggs, on top of the Hub. You have to complete the Mech in the garage next to Sully's, then attach the Whacker to it. This will let you enter the door at the far left of the island, using the spacebar to activate the Whacker.
Once you have attached the Mech Crank and the motor, enable the Mech Weed Whacker and use the spacebar to whack the weeds (you need at least two hits per section on weed growth).
Clearing the weeds from the entrance at far left (the Storeroom) will have to wait until you finish building the Mech walker, which is in the garage next to Sully's. The weed whacker attachment for the Mech is in Captain Zigg's quarters on top of the Hub. When the Mech is finished, climb aboard and use the weed whacker card. Aim with your cursor and press the spacebar to whack weeds.
Clearing the weeds from the entrance at far left (the Storeroom) will have to wait until you finish building the Mech walker, which is in the garage next to Sully's. The weed whacker attachment for the Mech is in Captain Zigg's quarters on top of the Hub. When the Mech is finished, climb aboard and use the weed whacker card. Aim with your cursor and press the spacebar to whack weeds.
its in the museum on mainstreet of steamworks island :)
It's Steamworks Island #14th Island
(The solution is at the related question "How do you beat Steamworks Island")
Well First you have to get the weed wacker. Then you go to the 2nd garage all the way to the left and start to hit them!
the crab on steamworks island is next to the living quarters
You go to Steamworks and head to the museum and there is the Deogen
steamworks island
There is a video walkthrough at the related link below. There are written WikiAnswers solutions at the related questions, as there are for all Poptropica islands. (How do you beat Steamworks Island) (What is the walkthrough for Steamworks Island)
Steamworks island