When rebuilding a 55H 3rd Port Quincy/Merc deflector with single ring Turners and gawd awful compression, the first time I tried to start it and doing so it snapped off the timing belt. I seen the same thing happen at a racesite to a Alky 44 on a Buyers hydro. Same thing happened the second time, so I went looking for a tighter belt in the pile I got finding 2 similar tighter ones out of some twenty new and used ones. I heard that someone had the same problem as well that the problem also happens with Mercs self energizing Lightning Ignition they used on some Merc 500s. That they resolved it by using an spring loaded idler pulley on the system to deal with slack belts or abrupt changes in belt tension. Does anyone have a picture of such an idle pulley setup system to stop belts from snapping so easy?