Correct sparkplug on 1991 200 HP

[Keithm18]

Hi Guys. Another quick one.

I noted in my manual that I should be running NGK BU8H plugs in my 1991 Mariner 200 HP, however the motor currently has NGK BUZHW plugs fitted.
The BUZHW plugs are shown for use in the 225 Motors and not the 200.

They are both surface gaps plugs.

Can you confirm what the difference between the two is and if I can continue to run the BUZHW plugs or should change them out?

If you've read my other thread I am having a few cold start and igling issues would these plugs have any impact on that?

Thanks.

 

[galamb]

Put in the specified plugs - hotter, colder, different resistance "could" = poor starting, crappy gas mileage etc.

The BUZHW's are a "colder" plug with more resistance than the BU8H's.

Surface gap plugs are "crappy" anyhow for cold starts and lower rpm running. A gapped plug will always start/idle better.

Surface gaps are designed for "sustained high speed running", unfortunately there is no spec for a "gapped" plug for your model.

Any gapped plug is "hotter" than a surface gap...

 

[Keithm18]

Hi All. Quick update. I got the correct plugs BU8H.

Hard start problem sorted now, will take it out on Sunday and see how she goes.