Outboard randomly loosing power

Hi<br><br>It´s my first time posting on the forum. It has allways been a great tool for getting information.<br><br>In first place I am from Argentina where we speak spanish so i apologize for my bad spelling.<br><br>Unfortunately I am having a problem with my outboard engine (a 60hp yamaha 2 stroke from 2009 with 520hs that was only used in a river) that my mechanic can´t seem to fix.<br><br>Engine works fine but it randomly looses power at any speed. Engine keeps running, rpms lowers and it dosent push the boat forward. I can fix it by going to neutral for a few seconds and then giving it thrust again. Some times this happens once in a halfhour trip or maybe 10 to 15 times. <br><br>My mechanic cleaned the tank, carburator, change spark plugs,  change parts from the fuel pump (it´s a kind of filter) and after all of this he thinks its not a fuel problem. I think he is right because i can run the engine at full throtle and  it runs great some times.<br><br>His latest suspect is the starter box or ignition box, i dont know the right name of this part in english.<img src="http://www.marineengine.com/boat-forum/attachment.php?attachmentid=22067&stc=1" attachmentid="22067" alt="" id="vbattach_22067" class="previewthumb"><br><br><br>Has anyone had problems with this part? What kind of symptoms should i see if this is going bad?<br><br>Do you have any other ideas?<br><br>Thank you very much!

Hello.

That picture is showing the ignition coil assembly. You should have 3 of those. If one is going bad, its resistance it will be different than the other 2. So you can try measuring the resistance for each with a multimeter.

If the coils all have a similar resistance, I would get a spark tester and make sure each plug wire can produce a strong enough spark to jump a 9mm gap. It's an inexpensive tool that is good to have. If one coil can't jump that gap and the other 2 can, then you know that coil is failing. Try doing this test immediately after the issue occurs. Also try doing the resistance measurements when the engine is cold and again when the engine is hot (to see if they change).

I really don't know if the ignition coils are related to your problem, but this is how you can do some basic testing on them.