6hp evinrude running on 1 cyl

[thegreenrabbit]

I have a 1977 6hp Evinrude twin cylinder (model 6704m). The top cylinder is not receiving spark. I have replaced the coil for the top cylinder and it is still not receiving spark. I have checked the wiring and it all looks like it is in excellent condition. I have not checked the parts inside the flywheel.
My Questions:

Am I correct to assume the next likely culprit is the power pack? The Motor has sat for over ten years but was used less than 50 hrs prior to being stored. I think the capacitors might have degraded.

Is there a way to bench test or test the power pack?

Since it is a CDI the only part in the flywheel is the magnet and trigger mechanism?

Are there two trigger mechanisms? one for each cylinder?

Many thanks,

 

[AlTn]

Re: 6hp evinrude running on 1 cyl

go to shop2.evinrude.com...find your year model and hp and you'll find diagrams of all your motor parts..were I in your shoes I'd unplug the connectors from the powerpack to the coils and clean the inside connections with electrical contact cleaner. I'd do the same with the connections that comes from under the flywheel to the powerpack. I'd then clean and sand the powerpack ground. If still no spark then the powerpack is the likely culprit. If you want to do further testing, a dva meter or dva adapter for a dvm is gonna be necessary, unless you have access to a known good powerpack.

 

[thegreenrabbit]

Re: 6hp evinrude running on 1 cyl

If I wanted to pull the flywheel to have a look at all of the electronic bits hiding underneath, what would be the proper protocol for that? I see the large nut in the center. is that the only thing holding it on? Do I need to note the position of the flywheel when I take it off and put it back on?

 

[Trickle56]

Re: 6hp evinrude running on 1 cyl

Yep. Your also gonna need a puller though. Just removing the nutt won't free that fly wheel. As for the position of the flywheel just line up the woodruff key (shear key as some say) on the crankshaft with the slot on the flywheel.

 

[AlTn]

Re: 6hp evinrude running on 1 cyl

you'll need 3..1/4" x 20 bolts at least 2"long with washers < use no.8 grade or higher for bolts and washers > and a harmonic <or bolt> puller..I got one from harbor freight part no. 37824...if you're missing on one cylinder only..it's unlikely that the 2 components under the fw are the culprits...you are correct < I think > that your power pack is suspect...or the connection in your plug boot to sparkplug is bad...if you got a new one with your coil, that would eliminate that....are you sure your coil is grounded?

 

[F_R]

Re: 6hp evinrude running on 1 cyl

Go ahead and look if it makes you feel better. But there is nothing in there to cause the problem. There is a driver coil and a sensor. The driver coil charges the power pack (BOTH cylinders), and the sensor tells the power pack when to fire a cylinder (BOTH cylinders, according to polarity of the passing magnets). So both devices are active in firing both cylinders, no way can they just do one.

You must have either a bad power pack or a bad coil. And you replaced the coil, so that leaves.....guess what.

 

[thegreenrabbit]

Re: 6hp evinrude running on 1 cyl

Thanks everyone. I was curious about the sensor and charging coil. I was wondering why there were not two, one for each cylinder and your replies answered that. The new coil came with a new plug wire. I checked the grounds and wiring first and after I put the new coil in. I'll be ordering a power pack and let everyone know. thanks again.