66 Merc 650 ignition

[nos1013]

I just bought this boat in Feb, which is my first boat motor. But I was an ASE auto mechanic several years ago, so I'm not totally clueless, just "a fish out of water", so please help! Question: I'm having problems keeping her running, would a weak coil in a magneto create a rich mixture scenerio? I tried one of those spark testers, and couldn't get any light, but it will start and run for up to 30 seconds, but not every time. It seems like the longer between times I try to start her, the more eager she is willing to start, but only for a short time. <br /> For the record, I've been thru the carbs (floats, needles,seats, gaskets), fuel pump, new seals/water pump parts/lube in the lower unit, adjusted the "looks like new" points, put new J4C plugs in her, wires check ok, compression is 105-115, had new brushes put in the starter (per Laddie), no arcing tracks in the cap, nor rotor, and I'm getting frustrated. Do I need to spend that $60 (oldmercs.com) for a new coil, or does someone have another suggestion? Any ideas will be helpful at this point! TIA!<br /> B

 

[Laddies]

Re: 66 Merc 650 ignition

1013, that engine may not light a neon it sounds like a mag problem, the mag should arc a plug with the ground electroid cut off on each plug wire, at crank speed, if not remove the mag from the engine, with the cap and the coil output strap exposed it should arc a min. of a 1/2 to 5/8 spark by turning the mag shaft (get a good ground on a vice or something it will poke you) Chances are it's pts. and cond, seldom a coil. the pts. are bad enough for price. I have never had luck cleaning them. They are dwelled at 48 degrees or gapped about .010, they should have from 33 to 37 oz. of tension to run properly. Any small engine shop or decent marine center should have equipment to test your coil and condensor

 

[nos1013]

Re: 66 Merc 650 ignition

Update: I took the mag apart and discovered a failing bearing with lots of small metal bits that appears to have been locking up the mag. The marine dealer sold me their last 2 points sets after the mechanic said he's never even heard of one of those coils going bad. I have to go to BRC for the bearings. Mercury no longer sell em. <br /> On a lighter note, the last time I stabbed the lower unit, it was stuck in reverse instead of forward. So I'm learning.<br /><br /><br />"I have not failed. I've just found 10,000 ways that won't work." Thomas Edison

 

[Laddies]

Re: 66 Merc 650 ignition

1013, if you can't find brgs they are available thru Sierra or NAPA

 

[nos1013]

Re: 66 Merc 650 ignition

Ok, I'll keep that in mind. Thanks Laddies

 

[nos1013]

Re: 66 Merc 650 ignition

Update: after replacing the magneto bearings, points and condensor, the motor actually fired cold without touching the cold start lever (I did have my thumb on the elec choke button).<br /> And if that weren't enough good news, I finally have the lower unit synched. It actually goes into Forward, Neutral and Reverse now!<br /> Thanks for the input on both, Laddies

 

[timmathis]

Re: 66 Merc 650 ignition

GOOD WORK GUYS!!!!