After spending a lot of time doing maintenance and service checks on my old 97 XP I was getting ready to fill the new oil injection lines and winterize it with RV anitfreeze. As the injection lines were getting primed by the pump at idle I noticed that the mag cylinder line was filling at a slower rate than the PTO. After they appeared to be primed I turned off the engine and checked the mag line. The oil was very slowly being drawn back up to the pump and emptying the line which was the exact opposite I was expecting if my check valve was leaking.
I pulled the carbs and used a pressure tester on it. At 30 lbs it was still holding air. I used paper clips and carb cleaner and it cleaned up the valve. It now held and then popped at about 2-3 lbs and held a vacuum over 10 lbs. Cleaned the PTO valve too just in case and it tested at about the same values as the MAG valve. This engine ran great the last time I had used it so the oil had to be flowing since I sometimes run wide open for a while. The line plugging must have happened from sitting for 3 years since I was careful when putting in the new oil lines. This engine would have blown if I had left it as is and not looked into the issue.
Now my 99 XPL (rebuilt in 2006) has me worried too since it sat for three years too I was not going to change the oil lines since they are not brittle and no leakage. Not sure if it is even possible to check those valves properly with oil in the lines since there is no writeup for that type of procedure. Checking these valves probably requires pulling the head pipe and carbs just to get down to them. A whole day of work at best.
I pulled the carbs and used a pressure tester on it. At 30 lbs it was still holding air. I used paper clips and carb cleaner and it cleaned up the valve. It now held and then popped at about 2-3 lbs and held a vacuum over 10 lbs. Cleaned the PTO valve too just in case and it tested at about the same values as the MAG valve. This engine ran great the last time I had used it so the oil had to be flowing since I sometimes run wide open for a while. The line plugging must have happened from sitting for 3 years since I was careful when putting in the new oil lines. This engine would have blown if I had left it as is and not looked into the issue.
Now my 99 XPL (rebuilt in 2006) has me worried too since it sat for three years too I was not going to change the oil lines since they are not brittle and no leakage. Not sure if it is even possible to check those valves properly with oil in the lines since there is no writeup for that type of procedure. Checking these valves probably requires pulling the head pipe and carbs just to get down to them. A whole day of work at best.
