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1984 mercury 60 hp 3 cyl

Jingle

Member
Hello everyone. I have a misfire at high rpm it comes and goes.how can I trace what cylinder is causing the problem and troubleshoot.
Thank you
 
Run at full throttle on the lake with a timing light hooked up as a " poor man's scope "------Might help pinpoint which cylinder has the miss.
 
Not really, but your problem sounds to me like that's what's happening. (I've had to replace a few of these over the years.)

If you live near the water, are ambitious, (and a cheapskate like me), you might buy one new coil and try it in all three locations. Then again, you could buy three new ones and...

Jeff
 
if you have a timing light, as Jeff said look at the light and see which cylinder drops, then you can swap 2 coils positive wires and plug loads, if the problem moves your coils are fine.

since we are all cheapskate, build yourself a diy dva adapter for $5 and test the trigger and stator. I had a 60hp 1985 same issue, just checking ohms on the 3 trigger wires showed a difference, after testing dva I found a drop right before the miss.

swapped trigger and worked fine since. I recorded some videos yesterday testing these mercs check YouTube in about a week or I'll try post a link here..
 
Ok guys I replaced the regulator and stator both new. Still wont charge to 14 volts. I'm getting 12v on the battery. Any suggestion. Same engine. Also I have strong spark on start up on all cylinder I checked. Once it gets hot it seems to get weaker spark on all cylinder. Now the stator and switch box, rectifier has been changed, even put on new coil to see if that would do it. Only thing I haven't replaced is trigger. Can that cause my problems.
Thanks
 
have you checked the coil resistance? coils can also start failing when hot, I would write down the numbers cold and compare when warm.. when last did you change plug wires?
 
No but I did but a new coil on just to see. And that didn't do anything. And it is on all the cylinders. Not just one. Never did plug wires. And I dont have a dva adapter.
 
Did you actually put a regulator on your Merc?

I am pretty sure that the original equipment on a 1984 60hp 3 cylinder is a rectifier.

There is a big difference.

With a rectifier it uses the battery as the stabilizing load and requires a lead/acid battery to work properly. AGMs and other fancy batteries will not work properly.

I know from my '85 60hp 3 cyl. the stater/rectifier combination put out about 12v at idle and about 17v at full speed, when the battery is fully charged it supplies about 13.5 volts from mid to full speed and the over voltage is absorbed by the internal resistance of the battery.

Hope this help .... Fish ..ON
 
Ok no rectifier. Ordered original part number battery was full charged so it will only show twelve at idle. But more at higher rpm
 
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