40 Johnson on Bass Tracker

P

Pumpkin Creek

New member

• May 27, 2014

• #1

My boat started running about half speed right after I switched tanks. The fuel line and ball are fine, I also changed the plugs. I have ran a few tanks of fuel through it and added sta-built. It will get up to 3000 RPM when a load is put upon the engine but will rev to max without the load.

 

R

racerone

Gold Medal Contributor

• May 27, 2014

• #2

Do a compression test . follow that up to see if you have strong spark on both.----Must jump a gap of 7/16" or more.

 

P

Pumpkin Creek

New member

• May 27, 2014

• #3

HTML:

racerone said:

Do a compression test . follow that up to see if you have strong spark on both.----Must jump a gap of 7/16" or more.

Click to expand...

I sure hope I didn't drop a piston.

 

P

Pumpkin Creek

New member

• May 27, 2014

• #4

What should the pressure be at for this 1995 Johnson 40 hp

 

P

Pumpkin Creek

New member

• May 27, 2014

• #5

Thank you so much for the valuable info. I guess it is not a secret, I know little about outboards.

 

P

Pumpkin Creek

New member

• May 28, 2014

• #6

Did the compression test, both chambers came back at 95, the engine was not warmed up. Top spark plug had oil on it, lower one didn't.

 

P

Pumpkin Creek

New member

• May 28, 2014

• #7

I don't think I did the test correctly, should both spark plugs be out?

 

R

racerone

Gold Medal Contributor

• May 28, 2014

• #8

Top spark plug had oil on it.-----That may indicate a number of things.----Bad spark plug.----No spark on that cylinder.----Too much fuel on top cylinder .---Is this motor running on a VRO pump or a simple pump off the side of the top cylinder ?

 

P

Pumpkin Creek

New member

• May 28, 2014

• #9

The book says it has a VRO pump

 

R

racerone

Gold Medal Contributor

• May 28, 2014

• #10

To me it sounds like the motor is running on one cylnder.-----Should not be hard to figure out why.

 

P

Pumpkin Creek

New member

• May 28, 2014

• #11

That's what I have been thinking. What should I do next?

 

P

Pumpkin Creek

New member

• May 28, 2014

• #12

It runs just fine on the bottom cylinder, the top cylinder ran but very shortly both plugs are brand new

 

P

Pumpkin Creek

New member

• May 28, 2014

• #13

Just removed the spark plug wires one at a time. Both cylinders are firing