Cylinder issue

[cenrique]

I have a 75 hp seahorse johnson 1983, 3 cylinders, two stroke. Today i put it in the water and it only went to 15 miles per hour, seems like of the cylinders is failing because the motor seems very lazy.Test compression is good on 3 cylinders, carbs just cleaned up, new spark plugs. Any ideas of what could be causing the loss of power?. Thanks in advance.

cenrique

 

[thefairlaneman]

Re: Cylinder issue

Are all three plugs firing? Each one has its own set of points and coil. One can stop and the others continue to fire.

 

[thefairlaneman]

Re: Cylinder issue

Are all three plugs firing? Each one has its own set of points and coil. One can stop and the others continue to fire. Also one bad/shorted plug wire will cause the same issue.

 

[Benny1963]

Re: Cylinder issue

dont think it has points .check spark on all cyls with spark tester
and post back

 

[kenmyfam]

Re: Cylinder issue

I have a 75 hp seahorse johnson 1983, 3 cylinders, two stroke. Today i put it in the water and it only went to 15 miles per hour, seems like of the cylinders is failing because the motor seems very lazy.Test compression is good on 3 cylinders, carbs just cleaned up, new spark plugs. Any ideas of what could be causing the loss of power?. Thanks in advance.

cenrique

Good starting point would be to know what kind of boat it is pushing !!!! and whatever other symptoms it is giving !!!!

 

[cenrique]

Re: Cylinder issue

Are all three plugs firing? Each one has its own set of points and coil. One can stop and the others continue to fire. Also one bad/shorted plug wire will cause the same issue.

The center plug is not firing, could this be a coil issue?

 

[cenrique]

Re: Cylinder issue

Good starting point would be to know what kind of boat it is pushing !!!! and whatever other symptoms it is giving !!!!

Its pushing a 17ft mfg fiberglass boat rated up 120 hp. The only two symtoms i noticed are, the loss of power, it only goes up to 15 mph and the other is that its using too much gas, i noticed how fast the gas went down in the tank.

 

[iwombat]

Re: Cylinder issue

How did you determine the center isn't firing?

Swap the coil to another cylinder and see if the problem follows it.

 

[ezeke]

Re: Cylinder issue

Swap the ignition coil, spark plug wire and spark plug with another and see if the problem follows the coil.

Edit: You are too quick, iwombat.

 

[cenrique]

Re: Cylinder issue

How did you determine the center isn't firing?

Swap the coil to another cylinder and see if the problem follows it.

A friend of mine pulled the plug cable of the spark plugs and the engine did not do anything.

 

[ezeke]

Re: Cylinder issue

"A friend of mine pulled the plug cable of the spark plugs and the engine did not do anything."

That won't tell you if the ignition coils are good or not. Try swapping the coils so we can see if you need to move on to more serious possibilities.

Oh, and disconnect the rectifier while you do these ignition tests.

If you want to do this yourself, you can download and print the free Troubleshooting Guide from CDI Electronics:

http://cdielectronics.com/portals/0/downloads/Troubleshooting Guide 2006.pdf

 

[cenrique]

Re: Cylinder issue

"A friend of mine pulled the plug cable of the spark plugs and the engine did not do anything."

That won't tell you if the ignition coils are good or not. Try swapping the coils so we can see if you need to move on to more serious possibilities.

Oh, and disconnect the rectifier while you do these ignition tests.

If you want to do this yourself, you can download and print the free Troubleshooting Guide from CDI Electronics:

http://cdielectronics.com/portals/0/downloads/Troubleshooting Guide 2006.pdf

Thanks, i will try to do that and would let you know. When you say other serious possibilities, what are you refering to?

 

[ezeke]

Re: Cylinder issue

Ignition coils are relatively cheap and easy to replace. Did you download the troubleshooting guide?