Spark Plug Gap

[skibumtx]

Just picked up a 2006 21V Launch and wanted to put some new plugs into it. Got the plugs, but I am not sure of the gap; the manual says .090, the old plugs were at .060 and the dealer said .045??? Is there a link to a spark plug gap table somewhere?

[Engine Nut]

Just picked up a 2006 21V Launch and wanted to put some new plugs into it. Got the plugs, but I am not sure of the gap; the manual says .090, the old plugs were at .060 and the dealer said .045??? Is there a link to a spark plug gap table somewhere?

The gap depends on what type of plug you bought. If you are using the platinum plugs (41-932) the gap should be .060. If you got conventional plugs (MR43LTS) the gap should be .045". What manual had the gap specified at .090"? I do the manuals at Indmar and I don't recall an error like that.

[skibumtx]

Thanks for the reply.
I am using Champion Double Platinum plugs 7940. The owners manual I found on the Supra website had the .090 on it. Where do I find the Inmar manual for this engine?

I put the plugs in at .060 and it runs real smooth, just need to figure out why I have a hum on the radio. Should I be using resister plugs?

[Engine Nut]

Thanks for the reply.
I am using Champion Double Platinum plugs 7940. The owners manual I found on the Supra website had the .090 on it. Where do I find the Inmar manual for this engine?

I put the plugs in at .060 and it runs real smooth, just need to figure out why I have a hum on the radio. Should I be using resister plugs?

The .090 is way wrong. I did a cross reference fron the AC 41-932 and came up with a Champion 7013 Double Platinum. You really don't get much benefit from platinum plugs in your engine.The conventional plugs (AC MR43LTS or Champion RS12YC) work just as well and a are a lot cheaper.

Did you have the radio noise before you changed the plugs? All the plugs we specify are resistor plugs.

You can get a copy of the Indmar Manual fromour website. Here is a link http://www.indmar.com/About/ContactI...Presentweb.pdf

[skibumtx]

I just bought the boat and it has been raining for a week, so I went ahead and changed out the spark plugs. So, I did not really notice it before. I'm going out today, so I will check it. Beaffed up the ground so it may be better.

[86Pirata454]

the noise go away? try to move speaker wires away from any wires with battery power

[skibumtx]

Yes, the noise is gone. I found the ground oin the amp was loose, tightened it up and cleared up the problem.