mercury 100 problems (I am afraid to ask)

[bmorton]

I have a middle 199X mercury 100. I had not used it for while when I took it out for a spin. Seemed to be running fine when it shut off (sort of like overheating). Restarted fine but when I returned I heard too loud of a knock.<br /><br />The compression in all 4 cyl.is 150. It starts easy. At idle it stumples badly every few seconds putting out a lot smoke. Over 1500 RPM it runs OK but with the knock. <br /><br />Is this the rods, reeds, or could a carb problem cause it. Guess which answer I want?<br /><br />Thanks for the help.

 

[Yepblaze]

Re: mercury 100 problems (I am afraid to ask)

Could it be one of the magnets in the flywheel coming loose and catching on the stator? (if so equipped?)<br /><br />Maybe a mechanics stethoscope or just a chunk of garden hose held to one ear whilst probed around the knocking motor might help locate the sound.

 

[Hooty]

Re: mercury 100 problems (I am afraid to ask)

Welcome to the iboats forum, bmorton. <br />The forum where we almost always tell folks what they want to hear. But not this time. When I hear "over-heated", I always think the worst. With the engine running (and knocking) you might try shorting each sparkplug out and see if you can detect any difference in the knock. If you can, it's more then likely a rod.<br /><br />c/6<br /><br />Hooty

 

[bmorton]

Re: mercury 100 problems (I am afraid to ask)

Thanks for the help. <br /><br />Yepblaze. fly wheel is OK <br /><br />Hooty, I will give it a try this week end. Also, if I move the pistons to TDC would I be able to see or feel any play if the rod or bearing was busted?

 

[Hooty]

Re: mercury 100 problems (I am afraid to ask)

Maybe. Give it a try.<br /><br />c/6<br /><br />Hooty