Roy's Magneto Service, Inc.

10/07/2026

ROY’S WEDNESDAY CHALLENGE — IT CLICKS, BUT DOES IT WORK?

A starter relay clicks when you turn the key, but the engine won’t crank. The battery passes its load test, and the starter and engine have been verified good.

With the relay energized and the circuit connected:
• Power input at the relay: 12.4 volts
• Power output at the relay: 0.6 volts
• The relay’s control power and ground both check good

What’s the most likely problem, and why would the relay still click?

We’re looking for the diagnosis AND your explanation!

Drop your answer below. Answer reveal tomorrow!

— Roy’s Magneto Service, Inc.

10/07/2026

Yesterday’s challenge answer was B — excessive resistance in the ground return circuit!

Ryan Krueger takes this one! He picked B and explained that the ground-side issue was keeping the starter from getting the voltage it needed. The actual ground-side voltage loss was 2.5 volts.

Shout-out to Ronald Fisk for being first to comment and recognizing a cable resistance issue! Ryan gets the win for choosing the specific answer and explaining why.

Thanks to everyone who participated!

— Roy’s Magneto Service, Inc.

10/06/2026

ROY’S TUESDAY CHALLENGE WOULD YOU REPLACE THE STARTER? 👀

An engine barely turns over, but the battery, starter, and engine all pass their checks.

WHILE CRANKING, you get these readings:

🔋 Battery voltage: 10.8 volts
⚙️ Voltage across the starter: 8.1 volts
📏 Voltage lost between the battery’s positive post and the starter’s power terminal: 0.2 volts

What do these readings point to?

A. Excessive resistance in the positive cable circuit
B. Excessive resistance in the ground return circuit
C. A faulty alternator
D. A seized engine

Drop your letter below! Bonus bragging rights if you explain your answer. 😂🏆

Answer reveal tomorrow!

— Roy’s Magneto Service, Inc.

10/06/2026

ROY’S MONDAY CHALLENGE

ANSWER REVEAL!

Somebody hide Ryan’s toolbox… he’s done it AGAIN! 😂🏆

The answer is a STRAP WRENCH!

Its strap wraps around the object and tightens as you turn the handle, giving you a grip without metal teeth digging into the surface.

👏 Ryan Krueger nailed the answer AND both bonus examples:
🔧 Oil filters
🔧 Plastic pipe/PVC

Thanks to everyone who played and shared! Keep an eye out for today’s challenge we’re still determined to stump him! 😂👀

— Roy’s Magneto Service, Inc.

10/05/2026

ROY’S MONDAY CHALLENGE — NAME THAT TOOL! 👀

Let’s see who’s spent some time in a shop…

I have no teeth, but I grip.
The harder you turn me, the tighter I bite.
My handle gets the attention, but my strap does the work.
I’m especially useful when you don’t want to leave marks.

What am I? 🤔

🏆 BONUS: Name TWO things you’d use me on.

Drop your guesses below. Answer reveals tomorrow!

— Roy’s Magneto Service, Inc.

10/05/2026

ROY’S FRIDAY CHALLENGE — THE ANSWER!

Ryan Krueger does it AGAIN! 😂🏆 Apparently, taking the challenge straight to the workbench didn’t slow him down!

The mystery part is a governor, and its job is to control engine speed! ⚙️

As the engine’s load changes, the governor adjusts throttle or fuel delivery to help maintain a steady RPM. Ryan correctly identified the part AND explained its purpose! 👏

Thanks to everyone who watched and took a guess! Keep an eye out for today’s challenge—we’ve got to find something to stump Ryan! 😂👀

— Roy’s Magneto Service, Inc.

10/02/2026

As things slow down for the season, now’s a great time to tackle those repairs you’ve been putting off!

Roy’s Magneto Service, Inc. offers parts, sales, repairs, and rebuilds, including:

⚙️ Magnetos and ignition units
🔧 Motors, starters, alternators, and generators
🚜 Engines—including oilfield engines and antique tractor applications
🛠️ Carburetors and clutches
🏍️ Razor electric dirt bikes and scooters

We also carry engine parts, bearings, bushings, belts, hoses, filters, spark plugs, gaskets, batteries, engine controls, gauges, and more!

We’re also connected with Mt. Pleasant Radiator LLC, specializing in:

🚜 Industrial, farm, and antique radiator repair
🔧 Gas and fuel tank repair

Dependable, quality workmanship for customers who need specialized radiator and fuel tank services!

Have something else that needs attention? There’s no harm in asking we may be able to help! Send us a picture, message our page, or give us a call. 📸📞

📍 Roy’s: 602 Industrial Ave., Mount Pleasant
☎️ (989) 773-9341
🕖 Monday–Friday, 7 AM–5 PM

Help spread the word by sharing this post. Thank you for supporting our businesses! 🤝

— Roy’s Magneto Service, Inc.

Call now to connect with business.

10/02/2026

ROY’S FRIDAY CHALLENGE — NAME THAT PART!

Today’s mystery comes straight from our shop! ⚙️📸

Look closely at the part video and tell us:

🔩 What is it called?
⚙️ What does it control?

Naming it gets you on the board… explaining how it works gets you bragging rights! 😂🏆

let’s see if you can identify this one without a part number! 👀

Drop your answers below—we’ll reveal the answer Monday!

— Roy’s Magneto Service, Inc.

10/02/2026

ROY’S WEDNESDAY CHALLENGE — THE ANSWER!

We owe you all an apology for going quiet yesterday the first of the month paperwork took over, and apparently invoices don’t care that we have a challenge to run! 😂📑

Now… we said we were done playing nice, and Ryan Krueger STILL came prepared! 😂👏

🏆 Ryan nailed the explanation, and James Hill had the right idea too!

When you hand-crank the engine, the impulse coupling briefly holds the magneto rotor while a spring winds up. Then it releases—SNAP! That spring spins the rotor quickly through its firing position, creating a strong starting spark. 🔥

If the electric starter turns fast enough to disengage the coupling, the dogs no longer catch, so there’s no spring-powered snap. The magneto is now turning directly with the engine.

Even though the ENGINE is cranking faster, the rotor can actually be moving SLOWER at the firing point than during that snap! If it’s still too slow to produce a strong spark, the engine won’t start. ⚙️⚡

The coupling also retards the spark for starting, so disengaging it changes the firing timing even though the timing adjustment hasn’t moved. 👀

Ryan, we’re starting to think you need to write the next challenge so the rest of us have a chance! 😂

Thanks to everyone who played! Keep an eye out for today’s challenge!

— Roy’s Magneto Service, Inc.

09/30/2026

ROY’S WEDNESDAY CHALLENGE!

Alright Ryan… we’re done playing nice. 😂👀

Today’s challenge is for the mechanics, farmers, oilfield guys, and old-school troubleshooters who really know their stuff.

An older engine equipped with a magneto and impulse coupling will start almost immediately when it’s hand-cranked.

But when you use the electric starter, it cranks the engine faster and refuses to start.

Here’s what you know:

⚙️ Fuel is good.
⚙️ Compression is good.
⚙️ Plugs and wires are good.
⚙️ Timing hasn’t moved.
⚙️ The magneto makes a strong spark on the bench.
⚙️ The impulse coupling snaps hard when checked by hand.

So here’s the question:

How can cranking the engine FASTER with the electric starter actually cause it to have a WEAKER spark than hand-cranking it? 🤔⚡

We’re not looking for a part name this time — tell us what is actually happening inside the magneto system.

NO PRESSURE. 😂🔥

Let’s hear it! 👇

— Roy’s Magneto Service, Inc.