I used a spanner to remove the boot of the first spark plug. Then I removed the plug and it looked OK, not oily or corroded. Even though it was the "easiest" one to access, it still put up a lot of resistance (removing the boot). I tried number 2 but it was impossible, there was no good purchase on the boot to pull it safely out and I did not want to push it laterally with the spanner. Removing the other four which are behind the first two is impossible because the bulkhead is too near the engine block and there is not enough room there. There are things on the way and I did have the ait filter cover off but it did not help much. The other side of the engine is even harder.