Hey Guys,
I am doing a complete rebuild/overhaul of an 05 rubicon. I have rebuilt the engine from crank up, new oil pump, new seals/o-rings, 2 rough bearings, new rings, new water pump, and gaskets. I have it back in the frame and trying to start it. I have cleaned the carb and blown all the jets out, clean as a whistle.

Some of the problems I am having now is that with the plug in, the starter has a very hard time turning over. Sometimes it will catch its stride and turn over for 10-15 seconds and other times it wont even touch it. I am jumping it from a parallel battery (diesel truck) so I know it is getting more than enough cranking amps. When the starter finally does turn it over, it is trying to fire, but won’t keep running without the starter. The plug has a yellow spark, and I am going to replace that, but I don’t think that is my main problem.

Another symptom is that when the starter is turning it over, and I add some choke, the engine will bog down and completely stop the starter. I’m not real sure why this would be happening.

I thought the timing might be 180 out, but I took a slo-mode video with the plug out and can see the spark with both valves closed. If it was 180 out, then the spark should be going just before the intake valves open. So I don’t think this is the issue.

Any ideas? I am going to replace the spark plug, make sure the muffler isn’t clogged and adjust the valve clearances. But after this, I am out of ideas.

Thanks in advance. I plan to post some pics in a bit.

Hey Guys,
I am doing a complete rebuild/overhaul of an 05 rubicon. I have rebuilt the engine from crank up, new oil pump, new seals/o-rings, 2 rough bearings, new rings, new water pump, and gaskets. I have it back in the frame and trying to start it. I have cleaned the carb and blown all the jets out, clean as a whistle.

Some of the problems I am having now is that with the plug in, the starter has a very hard time turning over. Sometimes it will catch its stride and turn over for 10-15 seconds and other times it wont even touch it. I am jumping it from a parallel battery (diesel truck) so I know it is getting more than enough cranking amps. When the starter finally does turn it over, it is trying to fire, but won’t keep running without the starter. The plug has a yellow spark, and I am going to replace that, but I don’t think that is my main problem.

Another symptom is that when the starter is turning it over, and I add some choke, the engine will bog down and completely stop the starter. I’m not real sure why this would be happening.

I thought the timing might be 180 out, but I took a slo-mode video with the plug out and can see the spark with both valves closed. If it was 180 out, then the spark should be going just before the intake valves open. So I don’t think this is the issue.

Any ideas? I am going to replace the spark plug, make sure the muffler isn’t clogged and adjust the valve clearances. But after this, I am out of ideas.

Thanks in advance. I plan to post some pics in a bit.