Plug Selection

1987 Merc classic 45 USA calls for the NGK BUHW-2 plug. The alternate plug for Canada and Belgium is the NGK BUZHW. This motor is currently running premix, auto blend was removed. Is there any risk or other reason to run either plug? When I was ordering parts at the local marine store, this is what I was supplied with, but had been running the USA BUHW-2 prior. Should I return them or give them a run through?

The "Z" plugs are meant for suppression of radio interference, which can affect sensitive instruments on the boat, and on outboards with an ECM, could cause interference with operation.

The CDI-type system on your classic 45 won't care about that. But if you run radios etc on your rig you may want a suppressive-type plug.

The difference between the BUHW and the "-2" is that the "-2" has more gap. So the ign system would have to develop more voltage for firing the spark plugs, which would tend to reduce fouling.

If your motor ran fine on the BUHW-2 spark plugs, and you have no RFI issues, there's no reason to run the "Z" plugs.

Last thought, perhaps Canada and Belgium have different rules/laws regarding RFI and the mfr is required to use the "Z" plugs. Just speculating!

HTH..........e

I was obviously sold them in error..should I go through the hassle of returning them or give them a go and see how it runs?