150 Merc

[LHarreld2]

I have a outboard mercury that will start and run in the yard with a hose hooked up. When I get on the lake and give it power it shuts down and eventually runs down and quits. Any ideas?
Lharreld2

 

[CharlieB]

Re: 150 Merc

A engine needs three things to perform, compression, ignition and fuel.

Check compression to ensure all cyl's are near the same.

Test the ignition with a 7/16 gap spark tester to ensure a hot ignition to perform well on ALL cyl's.

If BOTH of the above check out well then you can be sure your problem is in the carbs and it is time to clean them completely, reset the floats to factory specs and drive on.