Spark Plugs

[dejoeco]

I have an 02 22IR with the Mecr 5.7L 315 hp engine. It came with AC Delco 41-932's and the number has since changed to a 41-993. I try to do as much maintenance as I can, but when I had it into a shop they changed my plugs and put Ac Delco MR43LTS plugs in it.

1. I feel like I am burning more fuel these days. (is it an ethenol issue?)

2. Is this the correct plug?

3. recommendations please

[dogbert]

I have an 02 22IR with the Mecr 5.7L 315 hp engine. It came with AC Delco 41-932's and the number has since changed to a 41-993. I try to do as much maintenance as I can, but when I had it into a shop they changed my plugs and put Ac Delco MR43LTS plugs in it.

1. I feel like I am burning more fuel these days. (is it an ethenol issue?)

2. Is this the correct plug?

3. recommendations please

How many hours on your boat? It might be time to de-carbonize it.

[dejoeco]

I have about 550 hours on it.

[illiniboarder88]

what do you mean by "de-carbonize"

[dogbert]

Removing the carbon buildup that invariably forms on the valves.

[dejoeco]

Back to my original question about the plugs and then how do you remove the carbon?

[dogbert]

Not sure about the plugs. However, if you're burning fuel, then it may not be the plugs. At 400 hours, you want to replace the plug wires, too. I'd also check your distributor cap. Merc distributor caps don't last very long.

I put some Sea Foam in my gas to remove some of the deposits. SPBFAN's got a better way, but then he has all the cool toys.

[chpthril]

Not 100% sure of the plug cross-ref, but the MR is a Declo Marine plug. Ethenol will reduce fuel mileage. If your engine is port injected, the valves get de-carboned each time the injectors pulse, at least the back sides do, which is where carbon has a tendency to build up on carburated engines and can soak up the fuel-charge, creating a lean condition, low performance, thus more throttle in put from driver resulting in more fuel consumption. Carbon build up on the pistons and combustion chambers tend to cause an increase in compression ratio which creates more heat in the cylinder resulting in spark-knock/pre-ignition. I would be more worried about this then a drop in fuel range.

[dejoeco]

The engine is a throttle body fuel injection.