Help with spark plugs/ Engine ID

[geoff-nz]

Hi there

I'm a new member from New Zealand, new owner of a 1988 Glastron CX-19 with 3.0L Mercruiser Alpha1.

I'm in a bit of a bind regarding sparkplugs.

Engine serial# OC434492

I went and brought a set today from the local REPCO and his manual said to use NGK BPR6EFS.
The plugs that came out were NGK BPR4FS
The specs on the valve cover say AC MR43T which cross references to NGK BR6FS.
The manual I have been looking at online at boating info (Mercruiser#8) states champion RV9YC which is NGK BPR6FS.

I'm totally confused .

The plugs that I took out have a short threaded part approx 3/8" from seat and the BPR6EFS I have been sold are longer at about 1/2". I am scared to use them in case they contact the pistons.

Can anyone help out

Cheers

Geoff

 

[Don S]

Re: Help with spark plugs

Re: Help with spark plugs

The manual I have been looking at online at boating info (Mercruiser#8) states champion RV9YC which is NGK BPR6FS.

That manual is for a 470 engine, not a 3.0L

The specs on the valve cover say AC MR43T which cross references to NGK BR6FS.

Stick with what it says on your valve cover, it knows more than your auto parts store salesman

 

[geoff-nz]

Re: Help with spark plugs

Re: Help with spark plugs

Hi Don,

Thanks for your reply.

What got me confused was the plugs that came out of the engine being different from those specified.

Would you be able to tell me which manual relates to this engine?

Cheers

Geoff

 

[Don S]

Re: Help with spark plugs

Re: Help with spark plugs

Manual #10 is for an 88 3.0l engine, the serial number you posted is for an outdrive, not the engine. Look for a tag just aft and above the starter on the block.

 

[geoff-nz]

Re: Help with spark plugs

Re: Help with spark plugs

HI

The original plate is missing but there is a number stamped on a flat area on the stbd side of the block midway back - MO4318RA.

According to the manuals (if this is the number) the last 2 letters make it a 140hp-3.0L.

The ID sticker on the rocker cover says it is a 130HP MCM 3.0, so its all a bit contradictory.

The photo of the engine in the manual shows a totally different manifold/elbow setup and a side mounted shift linkage. Mine has a rocker cover mounted shift linkage. Does that matter?

I just want to make sure I get the correct parts.

Thanks for your patience

 

[Don S]

Re: Help with spark plugs

Re: Help with spark plugs

The blocks are the same 140 to 3.0. Manual #10 is the one you want.

 

[geoff-nz]

Re: Help with spark plugs

Re: Help with spark plugs

Hey thanks Don, thats very helpful.

Cheers

Geoff