Flathead with no spark

Swampthang

New member
Hey guys, it’s been a LONG time since I’ve been on Bob’s, so I’ve come back for some help! I have two questions to pose to you all. First, I have a flathead Briggs (old retired race engine) on alky, gets no spark. Air gap is correct, magnet is good, should I replace the coil next?

second question, it has a crank gear that has three different settings, I assume for standard timing, advanced timing, etc. if I put it on the standard timing, which timing mark do I use? My old engines never had adjustable gears in them so I don’t know which one to use! Thanks guys!
 
If the engine is not getting spark - replace the coil.
Obviously make sure that it is not grounded through a switch or something else first.
The plug wire is a likely culprit (possibly just the metal plug end.) You might try replacing it first. Have you checked the plug wire for ohm resistance? good quick check


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Brian Carlson
Carlson Racing Engines
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I will try that, hadn’t thought about testing that. It looks ok on inspection, doesn’t have a rubber boot or anything so it’s easy to check out. I will check it for ohms and see what we have. Thanks all for the input!
 
) I will assume that you're very sure the plug is good? A new one is not all that expensive!
Carlson made some good points, but I'm lazy, I would just buy a new coil and wire and plug boot, be done with it.
I doubt that the firing position is all that important, it should run at any of the indicated positions. Timing, just to get it running, or testing for spark, is important, but if it's anywhere near the right position, you should get spark. It's a 4 cycle so it should spark every time you turn the engine over one turn.
Are you able to pull the head off the engine? Both valves should be open at top dead center (TDC) on the first rotation, (exhaust stroke) and both closed on the 2nd rotation (compression stroke). Sorry if you know all this. Not this is going to help if it's not flattering, but it will help you make sure that your flywheel is close to the right position at the right time. Is the purchase of a degree wheel out of the question?
 
Alvin, "Its a 4 cycle so it should spark every time you turn the engine over one turn." doesnt really make sense at first but I guess it would have to with the newer pointless coil. Im assuming it would fire every other revolution with the old point setup.
 
Alvin, "Its a 4 cycle so it should spark every time you turn the engine over one turn." doesnt really make sense at first but I guess it would have to with the newer pointless coil. Im assuming it would fire every other revolution with the old point setup.
The old point setup also fired every revolution.
The reason being is that the points are also driven off the crankshaft. No way to get spark every other revolution unless driven from the camshaft. (camshaft turns at half crankshaft speed)
 
it has a crank gear that has three different settings, I assume for standard timing, advanced timing, etc. if I put it on the standard timing, which timing mark do I use? My old engines never had adjustable gears in them so I don’t know which one to use
That's a Dyno Cams billet cam. It's got a bunch of allen head screws on the front and markings to allow to advance or retard cam timing.
If I recall correctly, with the two lobes pointing towards the top, you'll want to use the mark between the tips of the two lobes.
I'm pretty sure that's correct, all my flathead stuff is in storage so I'm relying on memory.
 
I "think" he's talking about the timing gear on the crank, Bob, not the cam gear.
There are offset crank gears that offer 3 keyways machined in to them (for advance, retard, and stock cam timing.)
Think old-school like the Horstman crank gears of 30+ years ago.
 
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