New Spark Plugs for Mercruiser 4.3L V6 1991

[Adk1]

I want to install new spark plugs in my islander. anyone know off the top of their heads what particular brand and model of plug I should be getting?

[Chas0218]

AC Delcos.  GM motors run best on those for some reason.  But if you can't find them champions have been around for a while.  Just make sure it is a resistor plug or it will interfere with your electronics.

 

According to NAPA these should work.

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Spark-Plug-Copper-Core/_/R-ASP25_0388754273

Edited April 25, 2014 by Chas0218

[Glenn -Brazee]

Mercuiser service manual 1988-1993 4.3L (262 /V-6)Thunderbolt IV calls for spark plug 59571. As a personal suggestion, I would run NGK BR6FS or AC -MR43T. You may find others have a preference. Obviously don't forget to gap. Hope this helps.

[traveling man]

I am with chas, ac delco for your motor.

[bigblue]

AC Delco marine plugs they are plated and don't rust. MR43T for the 4.3 and 350 Merc .1991. Later Vortex engines take a different plug.

[Adk1]

Thanks guys will be buying the ad delcos. I have owned the boat for one and a quarter seasons. No idea when there have been new plugs installed. Will be replacing them none the less. Having said that and knowing the maintenance on the engine really, what else should I be looking to replace that I can do myself? Distributor cap I am thinking? Plug wires?

Edited May 6, 2014 by Adk1

[TileMan Dan]

Not a bad idea to due a complete tune up change oil and filter and new gas filter while your at it

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[TileMan Dan]

I know you said you had a whine on start up might want to check if a belt tensioning pulley is going bad on you if engine is equipped with one

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[Adk1]

I always change the engine oil and filter and lower unit oil. Haven't changed the fuel filter yet but that's a good idea...now to just figure out that part number

[TileMan Dan]

Just look on the filter

[Adk1]

Mercuiser service manual 1988-1993 4.3L (262 /V-6)Thunderbolt IV calls for spark plug 59571. As a personal suggestion, I would run NGK BR6FS or AC -MR43T. You may find others have a preference. Obviously don't forget to gap. Hope this helps.

Well, I went to Autozone expecting to get the AcDelcos..no dice. Ended up with the NGK's