This has me puzzled. There was a 235 engine in my truck when I purchased it last fall. After hooking up everything, it would not start. I cleaned the fuel tank, fuel lines, replaced the coil. points and condensor. I was getting spark and gas. A friend had another 235 in a truck that ran and was in great shape. I started the engine in the other truck and checked the compression. Engine started, ran good with good compression. We pulled the engine and put it in my truck. I'm now trying to start the engine in my truck. It will not start. I'm getting fuel and spark. The new engine was 12 volt when in the other truck. I used all my 6 volt parts when installing it in my truck. I'm not a mechanic. Any ideas?