No spark on 1969 Big Twin 40hp

S

Sport240

Seaman
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Feb 16, 2012
Messages
61
Hi folks,

Got my Big Twin cleaned up, changed the plugs, did some re-wiring, got rid of the automatic choke...ready to fire her up and...nothing....

Got fire pretty much everywhere, including the kill switch under the flywheel (if i disconnect it, it won't turn) but took out the plugs and grounded them on the head...no fire...

What am I looking at as a problem?

Any help is good help...

Thanx ahead!

JD
 
Joe Reeves

Joe Reeves

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13,262
Re: No spark on 1969 Big Twin 40hp

Did the engine have spark before you did the rewiring?

What do you mean... "you have fire pretty much everywhere?" Spark, voltage? The term "everywhere" needs to be defined.
 
1946Zephyr

1946Zephyr

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Re: No spark on 1969 Big Twin 40hp

How does the ignition system look on that bugger? If the coils are cracked, they probably need replacing.
 
S

Sport240

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Re: No spark on 1969 Big Twin 40hp

Hi guys!

On the right side, there is a (fuel pump?) to which alot of hot wires connect, including the wire to the kill switch and the wire that goes to the harness and up under the flywheel to the (coils?). The (fuel pump?) is where i replaced alot of wiring, including some splicing to old frayed wire, but there is voltage there, no problem. So right now, I am thinking either points or (coils?) under the flywheel.

Am I close?

JD
 
Joe Reeves

Joe Reeves

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Re: No spark on 1969 Big Twin 40hp

Sport240 said:
Hi guys! On the right side, there is a (fuel pump?) to which alot of hot wires connect, including the wire to the kill switch and the wire that goes to the harness and up under the flywheel to the (coils?). The (fuel pump?) is where i replaced alot of wiring, including some splicing to old frayed wire, but there is voltage there, no problem. So right now, I am thinking either points or (coils?) under the flywheel. Am I close?JD
Click to expand...

That's not a fuel pump... fuel pumps do not have electrical wires attached to them. THat is a vaccum controlled kill switch that prevents a runaway engine from destroying itself. If you have voltage applied to the center portion of that vaccum switch, you have no doubt caused damage to the points, condensers, and coils.

If you intend to keep that engine for awhile, I'd strongly suggest you obtain a service manual for it.
 
S

Sport240

Seaman
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Messages
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Re: No spark on 1969 Big Twin 40hp

Thanx for the great advice guys! I must admit that my neighbor was doing the testing with his meter. When i spoke to him about this this morning, he knew that there was no voltage on the wires; its me that got it backwards. Sorry about that. These answers confirm what we were thinking, that what's wrong is probably under the flywheel. Will have it off this weekend and will let you know!

Thanx again!

JD
 
Joe Reeves

Joe Reeves

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Re: No spark on 1969 Big Twin 40hp

When you get around to re-installing the flywheel, be sure to torque the flywheel nut down to 105 foot pounds. Anything less will result in a sheared flywheel key and damaged flywheel and crankshaft tapers.
 
S

Sport240

Seaman
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Feb 16, 2012
Messages
61
Re: No spark on 1969 Big Twin 40hp

Joe Reeves said:
When you get around to re-installing the flywheel, be sure to torque the flywheel nut down to 105 foot pounds. Anything less will result in a sheared flywheel key and damaged flywheel and crankshaft tapers.
Click to expand...

Good advice! Thanx! I'm getting a manual this week...I promise!
 
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