Spark Plugs

[kerryoneal]

I have a 2008 Moomba LSV with Indmar 325 V8.

I'm looking to change spark plugs myself.
Is there anything difficult about this, or is it as simple as taking out the old and replacing with the new?

Thanks!

[Badfoot]

Pretty simple. Take em out and put em in. Might have to check the gap depending on the plugs you get. Make sure you get the plug wires back on the correct plug. Shouldn't be any problem.

[kerryoneal]

On the spark plugs I bought the gap is .06, which is what the manual calls for.

Regarding the plug wires, I guess to be safe, change 1 plug and wire at a time.

One more question, How tight should they be?

Thanks!

[brain_rinse]

Here is the scoop on spark plugs for all Indmar 5.7L Vortec based engines (1996 or newer). If you have a 2006 or newer Assault 340 with catalyst exhaust, I recommend using the AC 41-932 or 41-993 platinum plugs gapped at .060". If your engine is not equipped with catalytic converters, I recommend using the AC MR43LTS conventional plugs gapped at .045".

Platinum or iridium plugs in an engine without catalysts are an un-necessary expense. Platinum plugs like to run HOT and LEAN. Our non-catalyst engines run relatively COOL and RICH. Save some money and use the MR43LTS plugs in those engines. The catalyst engines run a little warmer and a whole lot leaner, enough leaner in fact that they get better fuel economy, so the platinum plugs are much happier.

If you have an older, pre-vortec engine, use the AC MR43T plugs. The MR43T plugs are short reach plugs and the MR43LTS plugs and 41-932 or 41-993 are long reach plugs. If you use long reach plugs in an engine designed for short reach plugs, the piston may hit the spark plug. If you use short reach plugs in an engine designed for long reach plugs, you will experience incomplete combustion and poor performance.

I have no recommendations on aftermarket plugs. I know that the AC plugs that we use in the engines work, they are good plugs and the correct plugs for the engines and will not cause damage to the engine.

Straight from Indmar

[z28ke]

On the spark plugs I bought the gap is .06, which is what the manual calls for.

Regarding the plug wires, I guess to be safe, change 1 plug and wire at a time.

One more question, How tight should they be?

Thanks!

I would buy the same plug that's in it currently. Looks like a .045 gap is what you need on the 325hp vortec 350.

As far as tightness, I usually put my hand as close to the ratchet head as possible and get them good and tight. You can only put so much torque on it like that, and is virtually impossible to strip the threads in aluminum heads unless your the hulk.

Another tip: get some anti-seize and put a dab on the spark plug threads before you install. I also put some dielectric grease in each plug wire boot.