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Aftermarket trigger timing way out, backfiring

dickjacq

dickjacq

New member
I own a 1995 Mercury 50hp, 2 stroke.
There was no spark, so I replaced the stator and trigger with aftermarket parts.

When starting there would occasionally be large explosions. When I removed the spark plugs, cylinder 1 and 3 had a lot of lingering smoke. Motor never started.

I bought a timing light, and when turning over with the starter motor the timing marks did not show, indicating either I had wired it wrong or the part was wrong.

I looked up marineengine.com part details

Mercury Marine 50 HP (3 Cylinder) Outboard Motor Parts by All Engine Parts & Diagrams

Lookup Mercury Marine 50 hp (3 cyl.) outboard motor parts by component and buy discount parts from our large online inventory.
www.marineengine.com www.marineengine.com

The new trigger had right number of wires, and all colour coded correctly.

I ended up replacing the new trigger with my old trigger, the motor turned over fine, and timing was spot on now, 2° ATDC at idle and 20° ATDC with full throttle. Turns out it was only the stator that was dead.

My question is, what's wrong with the new trigger? Did I stuff up the installation or is the part wrong, or something else?

Screenshot_2024-01-26-21-23-30-69_e4424258c8b8649f6e67d283a50a2cbc.jpg


99021A3 is what I was after.
Screenshot_2024-01-26-21-23-48-47_e4424258c8b8649f6e67d283a50a2cbc.jpg

I bought this on eBay, same code as above.
Screenshot_2024-01-26-21-24-29-54_e4424258c8b8649f6e67d283a50a2cbc.jpg
 
Is that normal that the timing is completely off?
There was no issues with triggering the spark, but the timing must have been more than 30° ATDC, or 40° BTDC, because the stroke light showed a black area on the flywheel, compared to the old trigger.
How could it possibly be so far off?

I'm very sure the wires were connected correctly, hard to get it wrong when they are colour coded.
 
I had the same issue with a new Chinese trigger I put on a 40 hp. The new trigger was off replaced with a used trigger I found on EBay which worked fine. It must be a common issue with some of these aftermarket triggers.
 
I ended up returning it and getting a refund.
I don't understand how they can get it so wrong.

The replacement stator works fine though.
 
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