"Towing the Boat in Water" from my owners manual page 86 and 87, 2008 Challenger 180....I quote. Special precautions should be taken when towing a Sea-Doo Sport Boats in water. Maximum recommended towing speed is 24km/h (15 MPH). When towing your Sport Boats in water, pinch the water supply hose from the impeller housing to the exhaust manifold with a large hose pincher(P/N 529 032 500). This will prevent the exhaust system from filling which may lead to water being injected into the engine and filling the engine. Without the engine running there isn't any exhaust pressure to carry the water out the exhaust outlet. Caution: Failure to do this may result in damage to the engine. If your Sea-Doo Sport Boats must be towed in water and you do not have a hose pincher, be sure to stay well below the maximum towing speed of 23 km/h (15 MPH).
I recommend you purchase an owners manual, operators manual like l did. I bought my operators manual for the 2008 Challenger on EBAY for $19.00.