Advice on '64 Mercury

[Big Al1]

I've been tinkering with this old Merc60 6hp for a while now and I just can't seem to get her running good. It sometimes takes 20 pulls to start but has always started eventually. I've rebuilt carb, fuel filter and hoses, new fuel line, new plugs. I've got the carb adjusted to slightly rich. I think the problem is that the compression was 80 and 90. It was cold when tested and since the pull rope is on the cowling I had to test it with a rope tied around the flywheel. So I couldn’t pull it very hard, so the numbers may be higher. My question is: is this too low of compression? The motor idles pretty good @600rpms. But WOT is only @4600rpm (manual says 5400). At idle it seems to sputter or kick and sometimes dies when this happens. Does this engine need new rings (if pistons are good and cylinder walls are smooth)? Or could this be a symptom of points or coils?

 

[steelespike]

Re: Advice on '64 Mercury

Big Al,Your motor has a low speed mix. adjust <br />screw.Turn it in gently till it bottoms then out<br /> one turn. Then with the engine warm and under load Idling at 550-600 rpm adjust to best setting.<br /> Max rpm in my manual is 5,000 to 5400 rpm.<br /> If you are beefy and the boat doesnt plane I would say you probably wouldnt reach max rpm.<br /> Compression is low and slightly out of the 10%<br />tolerence.I think it should still start in a few pulls.It should have a good snappy spark blue and <br /> you should here it snap.<br /> It wouldnt hurt to check the system out.<br /> Before ser. number 1583853 point gap is .018<br /> after is .020.<br />60s before ser. number 2126764 use a 3/8 inch reach plug old number J7J set at .025. motors after 2126764 use a 1/2 in. reach old number L7J<br /> set at.030 <br /> If you dont have a ser. manual it would be very good to get one. After market manuals are available every where.<br /> Good luck.

 

[ODDD1]

Re: Advice on '64 Mercury

Al, I have fixed many of these old girls over the last 20 years, and compression in the 80 to 100 psi range is fine....they 'kick' at idle because the mix is too lean...are you testing this in a barrel with the fuel tank on the ground? the fuel pump will only pull up about 2 1/2 feet, making an engine intermittently lean out and die....leaking crankase pulse line to the fuel pump does this too, as will a leaking crankcase parting line...and like steelspike says, cleaning and setting the points will always help this little one idle better...

 

[Big Al1]

Re: Advice on '64 Mercury

Thanks for the responses. I do have a Seloc manual and I know that I have the wrong plugs in. When I bought the motor it had Champion CJ6 plugs (a common plug). I replaced it with the same. Do ya'll think the plugs may be making it hard to start? Can you buy the J7J plugs at an auto parts store? I haven't yet pulled the flywheel to check the points. Maybe tonight if I get my friends puller I'll pull the flywheel and check the points condition and setting. I'm not too sure on how to test for spark though. I've tried holding the plug close to the block and turning the flywheel with my hand and nothing. Must you turn the flywheel really fast? As you know, the rope is on the cowling. The motor is hard to start even after running it for some time. It starts easy when still warm though. I replaced the crankcase pulse line so I know it isn't leaking (it was leaking bad before). I may try the ole soapy water around the crankcase line to check for leaks.

 

[SpinnerBait_Nut]

Re: Advice on '64 Mercury

BIG Al1 Said

I'm not too sure on how to test for spark though. I've tried holding the plug close to the block and turning the flywheel with my hand

BIG Al, they make a tester that plugs onto the plug in which you can put the plug wire on it and when you spin the engine it will show the fire in a clear window.