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Won't run in the water

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Matthew A

New member
I have an 80s model 90hp Johnson 2 stroke. It will run like a champ out of the water and attached to the water hose. Once it's in the water, it takes several attempts to crank and will idle in nuetral and rev up. Once it is placed in gear, forward or reverse, it will cut off. If it does begin to run, it will only rev up so much, is very sluggish and will not go very fast and seems to start slipping like it's in neutral and will eventually die. Any ideas. Thanks in advance
 
Remove spark plugs.... check compression. What are the psi readings of the individual cylinders?

The spark should jump a 7/16" air gap on all cylinders with a strong blue lightning like flame... a real SNAP!... does it?

The terminology "crank" pertains to having the flywheel rotate... I believe what you meant to say is "it takes several attempts to start." If the electric starter is turning the flywheel... it's cranking.
 
Some will argue.-----My tester would show 120 + on these motors.---But perhaps wires from powerpack are going to the wrong coil.-----Plug wires going to wrong plugs ?----Sounds like it is running on 2 of 4 cylinders.--------Cylinder heads running same temperature on both sides ?
 
The tester I'd a cheap one, but since the readings are consistant on each cylinder would that possibly indicate that the cylinders are good and the gauge is faulty? Plug wires appear to all be correct. How do I check the temp on the cylinder heads? Could it be a lower unit problem?
 
Matthew A said:
The tester I'd a cheap one, but since the readings are consistant on each cylinder would that possibly indicate that the cylinders are good and the gauge is faulty? Plug wires appear to all be correct. How do I check the temp on the cylinder heads? Could it be a lower unit problem?
Click to expand...

Run it for a while, stop and feel the base of the spark plug or use an thermal radiation, infrared, temp gauge.
 
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