No power when in water

[GavOz]

115 Johnson outboard motor model 115ML78C - this motor is truly baffling us! Total engine rebuild been done, running full power with muffs on but as soon as in water - no power and runs rich. It seems like the motor exhaust gases cannot escape? have checked exhaust outlet - appears to be fine. All clear, is there something we are missing? Or need to investigate further?

Any ideas would be helpful.

Thanks Gav
Australia

 

[faztbullet]

Do a drop test as it will run fine and rev up on just 2 cylinders on muffs

 

[racerone]

How did you TEST full power on muffs ??-------It can sound really good to you running on only 2 cylinders and it will roar.----------Test for spark on all leads.--------------Check to make sure the orange wires from powerpacks are going to the correct coils.---------You did install a new diaphragm in the fuel pump I hope.

 

[Boobie]

Follow Fazt's advice and see what happens.