Just because your motor starts to knock...it doesn't necessarily mean that you need a rebuild. It is, however, wise to stop running the motor immediately as to not cause serious and costly damage.
Some times the knocking noise may be your lower unit.
First, have a compression check done on the motor. If that checks out, then pull the lower unit from the mid-section and start the motor, if you don't hear the knocking, you have an issue with the lower unit. You can also pull the drain screw on the lower unit and check for milky looking oil or metal in the oil.
Friday, March 28, 2014
1.) Check to see if the state you live in, requires a title on both the boat and the motor.
2.) It's not enough to see the boat running on the hose. See if the seller will let you lake test it and always have compression checked on the motor.
3.) Check the gear oil in the lower unit to see if water has entered. If the gear oil looks, white kind of milky, the lower unit will need to be resealed. If you find any metal like substance, then the lower unit needs to be replaced or rebuilt.
4.) If buying a pontoon boat, pull the plugs on the pontoons to ensure that they are not taking on water.
5.) Find out from the seller, how long the boat has been sitting and when any maintenance was performed.
6). If the boat has been sitting for any length of time, you will want to have the carburetors/fuel system checked out, remove any old fuel, check the fuel lines, change the gear oil and install a new water impeller, change the spark plugs and thermostats.
A little maintenance can save you thousands!