Mariner Spark plug problems!

[SimonStDavids]

This might seem like a silly question but i am trying to replace the spark plugs on my outboard and the I believe the correct ones to be NGK B8HS but the plugs that are already on the engine are BR8HS?

Apparently the extra R relates to a resistance version, but what does that actually mean and does it make any difference? So should i go with the B8HS or the BR8HS?

Has anyone got a Mariner 40E 6E9 and can recommend anything?

Thanks

Simon

[Jizm]

The R version means they have a resistor to prevent interference but you will be fine with the standard plug, B8HS.

[m chappelow]

it could be that the last time the plugs were changed that was the the only plug available at that particular time ,
,or that the last owner had a dodgy radio set up or something that was picking up interference from the engine perhaps .

[Locozodiac]

Originally Posted by SimonStDavids

the I believe the correct ones to be NGK B8HS but the plugs that are already on the engine are BR8HS? Simon

Does the factory recommended plug have a number 10 written to the right of the code number, if so, placing B/BR8HS standard plugs factory gapped to 0.7 mm will need to be regapped to 1.0 mm (that's what 10 stands for) to perform as same plug with 10 ending . If no number to the right can use any of the 2 as both costs same. Check service manual just to be sure.

It's the same example as B/BR7HS-10 (1.0mm) and B/BR7HS) (0.7mm) factory gapped.

Happy Boating

[SimonStDavids]

Ahh herein is a bit of the problem, I wasn't given a service manual when I purchased the engine so I have been putting pieces together from the internet!

The original plugs don't have any extra numbers and from speaking to a few people it seems like most outboards use the 1mm gap, so I figured I would regap to 1mm and see how it went.

Are there any symptoms I would recognise of incorrectly gapped plugs or am I letting myself in for a whole bag of trouble?

[uncle al]

the only spark plug listed on the epc for both electric and manual start is p/n 33-82372m or B8HS-NGK SPARK PLUG AND THE GAP IS 0.025 THOU

[uncle al]

i pressed the wrong button senior moment if you are experiancing intrferance on VHF fit suppresed spark plug caps p/n 814991m

[Polwart]

Originally Posted by uncle al

AND THE GAP IS 0.025 THOU

[Locozodiac]

Originally Posted by SimonStDavids

I figured I would regap to 1mm and see how it went.

Are there any symptoms I would recognise of incorrectly gapped plugs or am I letting myself in for a whole bag of trouble?

If no code number ending, do not regap, use as factory delivered, have not experimented using a 0.7 mm re gapped to 1.0 mm plug, definetely will work, but at it's optimum performance ?

Happy Boating

[SimonStDavids]

Originally Posted by Locozodiac

If no code number ending, do not regap, use as factory delivered,

Thanks for all the advise, I have installed the B7HS plugs as the factory supplied them and it is running like a dream!

Thanks again for helping me out.

Simon