Mercury 850 cap and rotor

[Thistledew]

Hello! My mercury 850 recently wouldn’t start due to no spark. I found the cap and rotor to be the culprit. I cleaned the metal on the inside of the rotor and cap and it started and ran fine. My question is should I replace the cap and rotor assembly or will it run as is for a while? Curious if anyone else had cleaned it up and had luck with the old parts. The cap and rotor are each $250!!! Very expensive for this old of a boat. Anyone know where to get the parts cheaper? Thanks for the help!

 

[Scott Danforth]

have you looked on ebay

 

[racerone]

Your location ?

 

[Faztbullet]

I have bead blasted many a cap and no problems. Just clean rotr with soft wire brush and replace the carbon and sprng….

 

[Thistledew]

Michigan. Very expensive used on eBay too. I’ll leep looking. Carbon and spring look great. Thanks!

I see some some oily residue inside the cap. Is that normal on these?

 

[merc850]

There's a gasket that goes between the cap and trigger housing, if it's missing fuel could enter the cap. I buy them at my Mercury dealer; there is also a sealed bearing on the shaft above the trigger disk that could be leaking. Smell the residue if it's gas/oil you'll know.

 

[racerone]

Find somebody that can test the cap and rotor.-----These are not automatic replacement items like on grandpa's 283 chevy !

 

[Thistledew]

Ok. Thanks everyone!