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Power loss

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Oldenburg17

New member
Hi,

I have a mid 90's Mercury 60hp outboard which starts and runs perfectly up to around 15mph. The problem is if I try to put the engine under full load and get above 15mph there's almost no extra power there. It will struggle on up to about 20mph but it sounds like there is a misfire at this point.

I have done a compression test which reads great and there is is spark on all 3 cylinders.

Any suggestions as to what the problem might be would be great!
 
what does the compression read?will the spark jump 7/16 inch with a good snap?is the timing advancing?is the vent open on the gas tank?if you squeeze the gas bulb does it perform better? the decision is whether you have a gas or fire problem.....use an inductive timing light and see if there is a fire problem at the failure point...how long has the motor been setting since it was run?....any work done to the engine prior to the problem?
 
Sounds like a carb problem. One of the three carbs might have a jet blockage issue, or it might be flooding (more likely). If so you can find out which one by performing a full power test: Open her up and let her do whatever she does. Give a minute of this nonsense, then shut her down instantly and pull the plugs. One of them will be...different.

Concentrate on rebuilding its carb.

Jeff
 
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