chrome hearts

chrome hearts

chrome hearts
chrome hearts

Thursday, April 17, 2014

no spark after new ignition coil

no spark after new ignition coil

I dont know much about small engines, trying to get this one working.

I replaced my old ignition coil because i read that it should read 25 ohms from plug wire to ground when it is disconnected. I did get spark before replacement, now I cant get any spark. The new coil doesnt read 25 ohms either! Did I get a bad coil? Is there something else I can try? I get a small reading on my voltmeter set to dc volts when the magnet passes by the coil. I replaced the spark plug also.

The old coil had wires entering a hole behind the flywheel. The new coils instructions told me to cut those wires. I ran the ground wire straight to a ground under the gas tank.

Any help would be awesome! Thanx!

Thanks, I didnt quite understand how the kill switch works and I had it wired wrong.

So, I now have spark. The engine idles smoothly, but under load it stalls. It also doesnt start very easily. I have to pull start it 5 times with the choke on then once with the choke off to start it, then it dies under load.

I have taken apart and cleaned the carb, new gaskets and diaphragm on the carb. I replaced the spark plug, ignition coil, spark plug boot. I took the head cover off and wire brush cleaned under there and replaced the head gasket.

After all this it still doesnt start easily and dies under load, any help? Whats next?

I have also replaced the breather and the rubber elbow grommets between the breather and carb.

When I had the carb apart, every port seemed clean. I could blow air freely thru every port. The only thing I couldnt do was remove the two plastic tubes extending from the carb into the gas tank. They have a hex head on them but I couldnt get them to budge. They were flexing and I was afraid to break them. I cleaned the screens on them as best as I could, and I was able to blow air thru them, they didnt seem blocked. I did not soak the carb in carb cleaner because I couldnt remove those tubes and I was afraid they would melt in the carb cleaner. I did spray carb cleaner throughout and everything seemed clean.

Today we got some snow, it seems to be running slightly better but still stalling under load. After all this work Ive done, it now back fires more than it ever has. I have attempted to tune the carb, but it seems I cant find a sweet spot. The slightest turn on that screw and it stalls.

I have tried running it without the gas cap also, no difference.

These pictures are before I took apart the carb.

Some times with a engine this old 1976 in this case you have to adjust those type carburators with the throttle wide open, work fast. You should be getting 3600 RPMs at full throttle.

While you got the cylinder head off you should inspect where the valves seat against the block, and check the valve guides. Just under the valve face is the margin where its tapered at a angle and meets the block. It should be the same width all the way around, if they arent you need a valve job.

While the valve is in the open position wiggle it, if there is a lot of side to side slop the guides are worn and maybe even the valve stem. If there is slop you need a valve job and new guides probably new valves as well.

No comments:

Post a Comment