What spark-plug 4hp Yamaha/ Mariner

[sam_uk]

Having some problems starting my outboard & thought I would change the plug.

Only problem I couldn't get the spark plug out. Off to buy a spark plug spanner now..

But does anyone know what plug goes into the 4hp 2stroke engines to save me two trips?

It looks like this

http://wn.com/Impeller_Change_Mariner_Yamaha_4_HP_Outboard

https://encrypted-tbn1.google.com/i...klZ6NUsw-SzoNEKwdwa3spNaKmrMgvqJ5di6BIHNeMgSB

Thanks

Sam

 

[VicS]

You dont say what year !! or give the serial number


However you should be able to find an owners manual for the mariner at http://download.brunswick-marine.com/download/preparesearch?mod=4&lang=EN
Not always easy to find the right one . Sometimes best to just enter "outboard" and search "all"

You may also be able to find the plug number in the parts lists at http://www.boats.net/parts/search/Merc2/Mariner/parts.html but is not always given

Probably something like NGK BPR7HS-10 or Just B7HS if its the old re-badged Yamaha


where B= 14mm, P= Projected insulator, R = resistor suppressed. 7 is the heat rating ( lower number is hotter with NGK), H= 1/2" thread reach, S= standard centre electrode.
-10 indicates that it is supplied ready set at 1.0mm gap but you may have to alter that to the gap specified in the manual

0.55 mm if its the old re-badged Yamaha . 1.0 if its a later US or European model

 

[ghostlymoron]

The recommended plug in the 2000 manual is NGK BR5HS
21mm plug spanner
gap 0.6 - 0.7mm
Assuming it's the same model as mine,

 

[VicS]

This I think is the manual for the old Japanese built models

http://download.brunswick-marine.com/filereader/file/pdf/4/enen/outboard/1985/mariner/43897r85.pdf


and this for later US and European models

http://download.brunswick-marine.com/filereader/file/pdf/4/enen/outboard/1998/2-stroke/10102z80.pdf

 

[sam_uk]

Thanks all

Managed to get the bugger out eventually.

It's a NGK BR7HS in case anyone finds this thread in the future..