Mercury losing power

[harbo]

I have a '93 40 HP Mercury 4 cyl. Approx 30 min. after running down the lake at full throttle the motor sounds like it loses RPMs and starts slowing down. (I am not sure about RPM Tach is acting up also) I have checked my fuel tank vents and have replaced the fuel filter. Does the same thing. While it is in this condition you can squeeze the bulb and not nothing changes. The voltmeter says that the stator is charging while I am running at full throttle. I have had several mechanics tell me that I need a new stator. Any suggestions?

 

[JB]

Re: Mercury losing power

Hi, Harbo.<br /><br />I agree with your tech that it is probably an ignition related problem. Seems to be heat related, too. <br /><br />See what happens if you remove the bonnet and add some air cooling to the top end.<br /><br />If it works then, put it on the muffs, at idle, and apply heat from a hair dryer to various ignition components to see if you can make it misbehave with heat. You may be able to identify what part is failing. Coils and powerpaks suffer heat failure also. If no luck there, replace the stator.<br /><br />Good luck.