1997 E225txecs Johnson problems need Help

[retiredDon]

I went out the other day and she started fine. As soon as I started to power up she ran nice 30-31 mph at 4900 rpm's. When we slowed down she was fine then when we went to take off we had it floored doing 8-10 mph and it would only go to 4000 rpms. When we powered down to 2000-2500 rpms we did the same speed.
Before it goes to the mechanic for a look see I'm hoping someone can guide me in the right direction.

The Johnson is pushing a 24ftWellcraft Coastal

 

[DangarStu]

You may have lost spark on one of the cylinders. If you disconnect one spark plug lead at a time (and earth it to protect the coil) you can see if things change and identify the cylinder causing the problem if that is what is going on.

Stuart

 

[retiredDon]

When you say earth it to protect the coil what do you mean. I never heard that before.

 

[Docksidemarineservices]

When you say earth it to protect the coil what do you mean. I never heard that before.

In other words, use a spark tester.