Merc 5.7L no power under load

[gmartindell]

I have a 2004 Mecruiser 5.7L. Toward the end of last season, I lost power under load (towing a skier). The motor idles and runs fine with no misses as long as I accelerate slowly. When I try to accelerate quickly, The motor bogs down. I noticed black goo that appears to be leaking out of the ignition coil near the coil wire. Is it possible that a bad coil could cause these symptoms? Can I check the coil by checking the resistance? If so, how do I know what the resistance should be? Thanks in advance for your help.

Glenn

 

[Fun Times]

Re: Merc 5.7L no power under load

Is this EFI or carbed? Is the coil hot?

 

[gmartindell]

Re: Merc 5.7L no power under load

It is carb'd. The coil was hot when it occured. I could rev the engine in neutral with no problems so I suspect that it is not a fuel problem but am open to anything at this point.

 

[Fun Times]

Re: Merc 5.7L no power under load

It is carb'd. The coil was hot when it occured. I could rev the engine in neutral with no problems so I suspect that it is not a fuel problem but am open to anything at this point.

It kind of sounds like the accelerator pump in side of the carb is not pumping the extra fuel when you hammer it, But if you accelerate really slow up to speed you could still reach top end. The accl pump will give the carb a extra shot of fuel for out of the hole.

 

[erikgreen]

Re: Merc 5.7L no power under load

To answer your question, a bad coil could cause those problems. The black goo might be the dielectric "filling" for the coil coming out. Or it might be unrelated.

I'd try a replacement if you think it might be melted.. a spare coil is about a $15 item.

With a completely bad coil the engine probably won't start at all, with a partially bad one it'll run very poorly.

Erik