Review on 🔧 MerCruiser Thunderbolt Distributor Ignition Sensor Kit - 87-91019A3 Replacement | 4.3L, 5.0L, 5.7L, 7.4L, 8.2L Engine - Upgrade: 87-91019A2, 87-91019A6, 87-892150Q02, 87-861780Q4 - Ignition Pickups by Matt Welch

50%. So far this has been my measure of success. I bought two of these to replace my old devices. I thought companies like Seirra and even Quicksilver would contract for these devices. There are only a few companies that manufacture them. The only difference is the name on the packaging. But for now I think I'm wrong. Of the two I bought, only ONE works! I just spent 8 hours troubleshooting why I had no spark on one engine, but my other engine was working fine. Finally. I put a worn, rusty, old block on top of a block that wouldn't catch fire. up to. I'm so pissed that I wasted an 80 degree weekend in Minnesota trying to fix this and now I'm questioning another device I installed! OEM price is about 3 times higher and Sierra price is about 2 times higher. IT WORKS OUT! 50% success is very bad! Even for electronic parts! If you can, go to OEM or at least "brand"!