'65 40hp dropping lower cylinder

Paul Moir

Admiral
Joined
Nov 5, 2002
Messages
6,847
Re: '65 40hp dropping lower cylinder

Lawn mower shop or marine shop by the foot. Some NAPAs will have metal core wire. You have to use 7mm wire for it to fit in the coils. I think 4' will cover it for a Big Twin.<br /><br />It really suprised me that the .5k or so of the carbon wires really did affect spark. Until I did a little reading up on the details of spark ignition. It turns out that most of the energy is transferred to the gas after the arc is established and the voltage across the arc drops to something about 100v. The wires eat up so much of that energy that misfires at part throttle are <br />a real problem.<br /><br />One of my engines, I'm embarrased to say, has a couple tubes of heat shrink shrunk over one of it's wires. It's been like that for two years now. :D <br /><br />Check the flywheel for signs of cracking around the hub and clean the hub & crankshaft with acetone (or whatever degreaser you have) before you re-assemble. Torque the flywheel nut to 50 lbs or so to exorcize (sp?!?) the torque wrench before going to 105.
 

dafox99

Petty Officer 1st Class
Joined
Jul 8, 2005
Messages
203
Re: '65 40hp dropping lower cylinder

Well, a buddy of mine pulled some old copper wires off a junk boat (at last count, he has over 60 in his lot), and I cut to size, and installed. Didn't spot any flywheel cracking and cleaned with degreaser. Runs like a striped ape again!<br /><br />I've read just a tad on spark ignition. Non-trivial, and while we seem to know quite a bit about it, I think there is quite a bit we don't. It's amazing that we have studied lightening (that's one big spark) for thousands of years, and even with the recent scientific advances, we still don't completely understand it.<br /><br />Kids have it out on lake austin right now for new years. Expect more repairs in the morning.
 

MCM

Lieutenant Junior Grade
Joined
Jun 1, 2005
Messages
1,201
Re: '65 40hp dropping lower cylinder

Glad to here ya got it goin Dave ;)
 

dafox99

Petty Officer 1st Class
Joined
Jul 8, 2005
Messages
203
Re: '65 40hp dropping lower cylinder

Thanks, MCM ... took it out with a buddy of mine who has a 60 mph Baja. Holy moly. About 400 ponies in a 25'boat. Out all day on the lake. His certainly got us places quicker, but at the end of the day, I enjoyed my little runabout just as much. Thanks for the help!
 
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