63 mercury runs like crap

[dennis1980]

I have a 65 hp mercury 650 that i just bought i take it out get 30 seconds down the river and it bogs out after that no matter what it runs like crap for the rest of the time. out of the water with the earmuffs it runs great full blast in or out of gear i dont get it mixing 40:1 this is my first boat i havent experienced ob motors yet but im gonna try any suggestions to help

 

[John Reynolds]

Re: 63 mercury runs like crap

My '56 Mercury was kinda acting like that. Turned out that the rubbing block on the points, where it rubs around on the cam shaft in the distrubutor, was wearing down so that the points were too close together. I needed to grease the cam lobe and readjust the points.

 

[JB]

Re: 63 mercury runs like crap

Do some basic troubleshooting, MM.<br /><br />No-load means nothing.<br /><br />Do a search for power loss. If you are getting 30 seconds of correct performance you may have fuel supply problems or you may have a heat problem.<br /><br />Good luck.

 

[12Footer]

Re: 63 mercury runs like crap

Buy a spark tester at any auto store, that has adjustable gap, or make one out of an old plug.<br />My guess is you are missing one or more cylinders. You can also tell somewhat by placing a hand on the head near each plug, after running it for a while. It will show which cylinders are not doing anything, as they will be cooler than the others.<br />And you need to cut the oil a bit, to 50:1, or 3oz to 1 gallon. You may have fouled the plugs by using too much oil. And she is an old girl. Test the compression on all four. They were great motors, as proven by it's vintage. but everything wears-out sooner or later.