Spark Plug Help, please

[Reming870]

Engine Serial # 6829350
Mercruiser 140 HP, 1984

Recommended: Autolite 144
Removed: Autolite 404

The 144's will not fit the hole bore size. Is it possible the block and head and different serial #'s and not original. Maybe the block is older than the head. I am getting the serial # from the tag on the head.

I am about to go strangle the guy I bought the boat from!!!

 

[IES99]

Re: Spark Plug Help, please

Engine Serial # 6829350
Mercruiser 140 HP, 1984

Recommended: Autolite 144
Removed: Autolite 404

The 144's will not fit the hole bore size. Is it possible the block and head and different serial #'s and not original. Maybe the block is older than the head. I am getting the serial # from the tag on the head.

I am about to go strangle the guy I bought the boat from!!!

Don't strangle him, after all the boat is 26 years old! Who knows what may have been done to it over that time. AC MR43T plugs are what most of these engines use. Good luck.

 

[NHGuy]

Re: Spark Plug Help, please

What plugs did you take out? Oops, you answered already. Check the temp rating of the two plugs, if same just copy what is there.

 

[Reming870]

Re: Spark Plug Help, please

There is a big length difference between the two plugs. The 404 is longer than the recommended 144.

 

[Fun Times]

Re: Spark Plug Help, please

You should try using either mercruiser part number 33-59571, (NGK BR6FS), Or if you can't find any of those numbers at a mercruiser dealer, then the new part number form mercruiser is 33-898264001, They are now AC Delco style spark plugs.

NGK BR6FS
AC Delco, MR43T
PS, Both of these spark plugs can be found at most auto stores as well.

See number 8 in this link.
http://www.mercruiserparts.com/Show...63&bnbr=100&bdesc=DIGITAL+IGNITION+COMPONENTS

And here is all of the parts to your engine.
http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=41261


Here's a cross reference sheet, If you would like to, Scroll half way down the page and look for a set of numbers, 4323 BR6FS .
http://www.angelfire.com/extreme4/skidoolympique/SPARK_PLUG_CROSS_REFERENCE.htm

Good luck.

 

[sethjon]

Re: Spark Plug Help, please

Didn'y you pull plugs out? Then replace with the same ones.