1974 650 Mercury 65 Hp No Power

BIGDOG2594

Cadet
Joined
Jun 23, 2008
Messages
13
I took the plugs out, look to be in good shape. Nothing out of the ordinary. Took off the distributor cap and noticed that the points were corroded and the rotor was also a little corroded with a little bit of dust in the bottom of the cap. So I took my handy little dremel and polished them up a bit. Gonna put the muffs on and start it up to see if it will idle high again. Then I will pull the spark plug wires, one at a time and make sure I have spark on all three. Does this sound right? Is it possible I was just not getting a good connection on the points and the rotor and that caused my problem. Boat lacks power with WOT, but no other noticeable sounds or problems that help me go in a specific direction. Sounds pretty fine but just won't get up. What would be next to check? Compression? I can check that with a gauge and just turning the starter wheel one at a time right? Do I leave the other plugs in if and when I test the compression one at a time? Thanks in advance!
 

BIGDOG2594

Cadet
Joined
Jun 23, 2008
Messages
13
Re: 1974 650 Mercury 65 Hp No Power

Help....fishing Derby This Weekend And Need To Get Back To 100%. Anyone?
 

BIGDOG2594

Cadet
Joined
Jun 23, 2008
Messages
13
Re: 1974 650 Mercury 65 Hp No Power

Ok, update.....Replaced the plugs, cleaned the distributor cap connections. Ran it with muffs and sounded good. Put it in the water, same lack of power. Pulled the spark plugs, two were visibly firing (black marks on the connector), one didn't. There was gas in the water for sure. I think the bottom cylinder isn't being fired. checking compression and spark testing today! Does anyone have any suggestions? What about parts, where the heck can I get a distributor and wires for this bad boy? Thanks in advance.
 

noahnsteph

Seaman
Joined
Aug 4, 2007
Messages
58
Re: 1974 650 Mercury 65 Hp No Power

Unfortunately distributer parts especially the cap is getting hard to find for 1973-1975 Mercury 650s anymore due to them being discontinued. New old stock caps go for over $200 nowadays. I found a place in KC that had good used ones for around $100 and new ones for $200 but otherwise your best bet is Ebay.
 
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