1997 Venom 200 knocks when in the water but no noise on the hose

[cwestTX]

New to this page. Ive been raking my brain trying to figure out this Venom 200. Just bought the boat a week ago and ran it on the hose and check compresion when i bought it. Runs perfect on the hose no irregular noises in or out of gear even when a given a little throttle. When I get it on the lake I hear a knocking sound in the motor. Only when in the lake. Carbs have been cleaned tune up done ect. Has a 24 pitch 14.5 Raker prop and good water pressure from the pump. Could a bent prop cause this? Any ideas before I send it to a mechanic to check out? Thanks

 

[cwestTX]

It is a two stroke with the oil pump removed

 

[racerone]

Are your compression numbers a secret ?-----And they all run perfect on a hose as there is no work to do.-----Will sound really nice running on 5 of 6 cylinders.-----Do you have spark on all 6 leads ?

 

[cwestTX]

all cylinders were between 105-110. I put new plugs NGK gapped to .030 in when I bought it havent checked for all six to have spark. That didnt cross my mind in this case

 

[Bosunsmate]

Pull out all your spark plugs and look for one/some with different colours

 

[Faztbullet]

When it knock in water is this in gear or neutral?

 

[racerone]

Check gear oil.----See if there are chunks on the drain plug magnet.

 

[cwestTX]

Just changed the plugs when I bought it last week. The new ones all still look new. Makes the noise in gear and in neutral. Boat is in the storage building will pick it up tomorrow and planned on draining the lower oil friday night.