1966 110 hp Mercury inline 6 no spark on 3 cyl

[allenprimo913]

i have this motor running and in the process of adjusting the carbs and guess
WHAT!!!!!!
now it does not start... i have no SPARK on 3 spark plugs
i have 110 hp 6 cyl: 2 coils, 2 set of points, 2 condensers and 3 carbs.

which part could be bad. HELP!!!!

 

[CharlieB]

Re: 1966 110 hp Mercury inline 6 no spark on 3 cyl

Switch the coils to see if the problem switches to the other 3 cyl's, if Not, then clean and regap the points.

 

[allenprimo913]

Re: 1966 110 hp Mercury inline 6 no spark on 3 cyl

thnks i will do that when i have the chance agai

 

[gungalunge]

Re: 1966 110 hp Mercury inline 6 no spark on 3 cyl

I have a different engine .. but here is what i found out one day . i started to see spark drop off . and perfermance problems . it s a late 74 inline . again dont't asume i am right , the distribitor bearings where wiped out , i used an ir temp gun pointed it all over .. "snap on tools " the red dot temp reading thing > the distribitor was hot while running . red hot . I dissassembled the distribitor unit . the bearing the top one where the timing gear picks up the timing belt was shot . it dry rotted the t belt as well . I replaced the bearings in the distribitor housing with real good new ones .I put grease on them too . and wow what a difference , and a new timing belt .I used the dial indicator method . this was a mechanical failure that made 3 of my cylinders low on spark . simple fix perhaps is a new disrtibitor . pushing the bearings off and greasing them and cleaning everythng was a 40 dollar repair and the leg work , there or so finding the right bearings .

 

[allenprimo913]

Re: 1966 110 hp Mercury inline 6 no spark on 3 cyl

i can not perform the dial indicator setup process

when i had the #3 piston on TDC and move my distributor,

i dont see any changes on my Ohmeter reading? what should i expect to read?

help

 

[cjack56]

Re: 1966 110 hp Mercury inline 6 no spark on 3 cyl

i can not perform the dial indicator setup process

when i had the #3 piston on TDC and move my distributor,

i dont see any changes on my Ohmeter reading? what should i expect to read?

help

A couple of questions:

(1) Where are you taking the ohm meter reading?

(2) Did you try swapping the connections on the two ignition coils like someone else suggested?

If you have spark on 3 out of 6, you have to figure what parts of the ignition system are associated with only 3 cylinders. The coil is one, the points and condenser are the two others that come to mind. Unlike the coils, you can't just swap the wires on the two sets of points, but you CAN disconnect them from power and see if they make & break contact as you turn the flywheel (with ignition off and all the plugs out).

By the way, WHICH 3 have spark, and which 3 are dead?

It's a simple system, troubleshooting is straight forward. Don't let it beat you.

Here's a good place to start: http://maxrules.com/oldmercs/timing/57.pdf

Good Luck!

 

[emckelvy]

Re: 1966 110 hp Mercury inline 6 no spark on 3 cyl

Pull the coil wires from both coils. Check for spark directly out of the coils. If you have an extra chunk of spark plug wire sitting around it's a bit easier to check by sticking one end in the coil and the other end <1/2" from the block. Otherwise you can unscrew each coil wire from the distributor and then plug back into the coil for spark check.

If you get spark out of both coils, but no spark at 3 cylinders when everything's put back together, the rotor is bad. It handles both sets of sparks (for cyl's 1-3-5 off one set of points/coil and 2-4-6 off the other set) and one section of the rotor is arcing to ground.

If you get spark out of only one coil, the most likely cause is a dirty set of points. Clean/gap/set dwell on both sets of points.

You can check the points for continuity by using a meter on ohms scale. Disconnect the brown and white points wires from the terminal block on the Port side of the motor. Check one wire at a time to ground, as you move the flywheel thru at least one full revolution. You should alternately see an open circuit when the points are open, and a short (or very low ohms) when the points close. If you don't see this on one set, that's the bad one.

If you remove the points to clean them you'll definitely need to set the dwell. The attached pic of the dwell plate should come in handy. A search of previous postings should find good instructions for doing so (or check your manual).

Anyway, there's a few things to look at. Let us know what you find.....ed

 

[Fuzzytbay]

Re: 1966 110 hp Mercury inline 6 no spark on 3 cyl

If you were setting the max timing, with a dial indicator, and you tried to find the point where the point opens, by turning the distibutor, you must first have removed the cap, and held the rotor so it to didn't turn. Otherwise, it won't work. If you do Emckelvy's test of turning the flywheel, through one rotation, and your points do not open, IE infinity reading on the ohms scale, then you have to re gap the point, since they are not opening. Obviously one of the two points is opening, the question is, if your lack of spark is from the other point, or the other coil.