8.1l Volvo Penta issue

[Viirrma]

Over the last month I noticed my cobalt losing power and running a little rough. After some quick checks, I’m getting spark to all plugs but two of them are getting washed out with fuel. They are very clean compared to the rest. They are the first cylinder on the left and the third back on the right, facing the rear of the boat towards the engine. Any ideas on why that’s happening?

 

[alldodge]

No spark on 1 and 6

2-4-6-8

1-3-5-7

The 8.1 using individual coils, I would see if the coils have power when key is ON. If they do swap coils around to see if the problem moves with the coil.

If it does not move with the coil then Need to check connections

 

[Viirrma]

Wouldn’t there be no spark if coils weren’t getting power?

 

[alldodge]

Wouldn’t there be no spark if coils weren’t getting power?

Not necessarily, the coil has 2 windings, a primary and secondary

The primary is powered by 12V and when the negative terminal on the coil is grounded the magnetic field collapses and sends the spark out the secondary winding. The ECM grounds (switches) the negative terminal on/off

Things that can keep the coil from working
One of the windings are damaged
The ECM stops switching the coil
Bad connection to/from the ECM