Troubleshooting a Mercruiser 5.0

Just a quick tip today for any of you DIY people out there.  This is regarding troubleshooting low power/acceleration of any carbourated boat motor.

My boat would not get up on plane last summer.  I would peg the throttle forward, and only get sputtering and sporadic bursts of power.  I was perplexed and annoyed so I pulled it out of the water and began troubleshooting.

Originally I suspected bad gas, or something wrong with the prop.  Prop looked fine, and I filled the tank with fresh gas and added fuel treatment to it to remove any water if there was any.

I also changed the spark plugs as after checking one of them, it was rather corroded and warn out.

Put the boat back in.  No change!  Same problem.

Pulled the boat back out.

Moving down the line of electrical connections, next I removed the cap/rotor.  This is what  is pictured above.  Bingo.  As you can see, all the contacts are green with corrosion. 

Now, there are 2 solutions to this problem.  1. Take a wire brush and clean each contact until it is back to shiny copper color.  2. Buy a new cap/rotor to fit your motor.  I went with option 1 and the boat ran great all the rest of the summer.  Will probably buy a new part next year.

Feel free to comment with any boat questions as I have been through many repairs  and problems.  Always happy to help.

Thanks for reading.