‘92 Johnson 60HP seems like not full power

[spacerust]

Motor was running great, but the other day while coming back from a fishing trip, it seemed like I lost some power while running. I had to putt back in because I couldn’t get back on plane. My first thought was a spun hub. Ruled that out today. I had just put new plugs about three weeks ago, compression on all three cylinders is between 135-140. I don’t hear grinding when engaging in forward or reverse. Carbs were cleaned around March of this year. It turns on fine and isles as it always did- any suggestions as to where I should start from here?

 

[racerone]

Test spark.----Good spark will jump a gap of 3/8" or more with ease.----Compression was tested today or last month ?-----And does telltale hose come off side of the block or the top ?---Water pump impeller changed recently ?

 

[spacerust]

Compression was checked this morning. Telltale hose is out the side and it spurs out water as it always had. I just came in from turning it on (I was thinking about taking the carbs off again and cleaning them) but read on here about pulling each individual spark plug while running. Turned motor on, pulled top plug wire- motor turned off. Plugged back in, turned motor on again and pulled middle plug wire- motor turned off. Plugged back in, turned motor on and pulled bottom plug wire and it idled fine. So, in conclusion, pulling the top and middle plug wires turns the motor off and bottom one pulled will keep motor idling. I did get a little shock pulling the first two plug wires. Sounds like I’m not running on all cylinders although compression is good. Could it be the bottom coil?

 

[spacerust]

I will check the spark on the bottom spark plug and report.

 

[racerone]

Does the tell tale hose come off the side of the engine block ( exhaust manifold ) or off the top of the block.-----Good spark will jump a gap of 3/8" with ease.

 

[spacerust]

It comes off the left side of the engine block.

 

[racerone]

There was a service bulletin that came out in 1994 to move the telltale hose to the top of the block.-----The latest water pump kit comes with parts / instruction on how to do cooling system modification.

 

[spacerust]

I will look into doing that mod. I checked the spark gap and the bottom coil wasn’t getting any spark. I cleaned the connections and it is getting 3/8 spark now. I have an spare coil and if it does it again- will change and order another spare. I will do a test run tomorrow and post how it goes.

 

[spacerust]

Took it out today and still doing same thing. I did feel like it was surging a few times and I did get on plane once; but I would stop and try again and out of maybe six or seven times, only got on plane once. Checked coils and they are within spec, checked spark plug wires and new plugs. It looks and feels like a spun hub, but I marked the hub and it didn’t move at all. Gears aren’t grinding, starts right up and everything; but wondering if I should drop the the lowe unit and check the forward gear?

 

[oldboat1]

Think I would try the drop cylinder test at speeds. Might repurpose a timing gun -- no light means no spark.