Testing Mantis Tiller Coil

[OverKnight]

Thanks for the explanation; it makes sense. Doesn't help me very much if I need a coil, but from a business perspective, it's understandable why parts for a 20-year old machine are no longer available.

[OverKnight]

Okay, getting nowhere fast...

I pulled the muffler off to check the screen, but there was no screen, so we can rule a clogged screen out. I was able to push on both rings and they moved easily, so I don't think the problem is there. I put my spark tester on, and couldn't see any spark at all. I put the new NGK BPM6A plug on (gap set to 0.025", and flywheel-coil clearance is 0.012"), and now there's a spark. I tried starting it, but it doesn't even pop. I took the flywheel shroud off and used a drill motor to turn the engine over quickly. I could hear it trying to run, but when I took the drill motor away, it immediately died. I looked at the plug again, but now it doesn't look like it's getting gas. Off comes the carburetor, and I do a quicky cleaning (disassemble, spray carburetor cleaner into everything, reassemble). When a press the primer bulb, nothing is going into the carburetor, and the primer bulb pumped vigorously before I removed the carburetor. I inspect the fuel lines, and the clear one going to the primer bulb is rotting.

I'll try to pick up a new set of fuel lines tomorrow. Is it really important to have the spark arrestor screen in the muffler? If so, I'll pick one of those up, too. Is a service manual for these engines available? I couldn't find one on-line.

Why there was no spark through the tester, I don't know; I'll try it on another running engine. It's not like there's much that can go wrong with these...

Thank you.

[OverKnight]

Success!

I bought a new fuel line kit, and went through the carburetor, but didn't find anything amiss. After a few pulls, it started started. and after a few minutes of warm-up I adjusted that carburetor. It now runs great; I dethatched my backyard, and it didn't miss a beat.

I'm figuring the spark plug was the initial issue, and then the fuel line, because when I first suspected the coil, it was getting enough gas for the spark plug to be wet. After installing a new spark plug, I could see a spark, but the plug remained dry. The lesson here is, when you fix one thing and it still doesn't run, go back to the basics; compression, fuel and ignition.

Thanks again for everyone's advice.