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dpolen
03-27-2007, 02:06 PM
My 5.7L Vortec engine has just over 500 hours on it. How often are you supposed to change the plugs?
I bought the boat last year with 475 hours. I have no idea if the spark plugs were ever changed. I think this would be cheap way to buy a little peace of mind, but I have never changed plugs with the exception of those on my old SeaDoo...this is a little more complex of an engine than that guy was. Thoughts?

Thanks!
Doug

erkoehler
03-27-2007, 02:26 PM
If you do change them, do it one at a time, and don't mess up the plug wires!

BrianM
03-27-2007, 02:26 PM
I would go ahead and change them. It is a pretty simple task and will give you piece of mind. I would also go ahead and change the wires, cap and rotor while I am at it. That will fix you up for the next 2-3 seasons.

east tx skier
03-27-2007, 02:47 PM
I do the plugs every spring and the wires, cap, rotor, and PCV valve about every 3 years or so.

wesgardner
03-27-2007, 03:41 PM
When you change plugs (yearly) don't forget to gap them...

east tx skier
03-27-2007, 03:54 PM
On the Ford, 0.035.

Engine Nut
03-27-2007, 05:06 PM
My 5.7L Vortec engine has just over 500 hours on it. How often are you supposed to change the plugs?
I bought the boat last year with 475 hours. I have no idea if the spark plugs were ever changed. I think this would be cheap way to buy a little peace of mind, but I have never changed plugs with the exception of those on my old SeaDoo...this is a little more complex of an engine than that guy was. Thoughts?

Thanks!
Doug

Our maintenance chart says spark plugs every 300 hours or annually, whichever comes first. A Vortec 5.7 Indmar/MasterCraft engine takes AC MR43LTS plugs gapped at .045".

Engine Nut

Doug G
03-27-2007, 05:09 PM
I do the plugs every spring and the wires, cap, rotor, and PCV valve about every 3 years or so.

Any reason why every year for the plugs? Do you put that many hours on?

east tx skier
03-27-2007, 05:20 PM
Any reason why every year for the plugs? Do you put that many hours on?

No, I don't put that many hours on it. An engine tune up is listed as annual maintenance in my manual, but I think a full annual tune up given my roughly 40 hours per season, is overkill. However, the plugs are, as mentioned previously, cheap, and I can't imagine that sitting in the fogging oil over layup is all that great. So I change them each spring (AL 764 copper).

dpolen
03-27-2007, 05:51 PM
Thanks guys! This is one of the reasons why I really like this forum.

dpolen
03-28-2007, 10:10 AM
Our maintenance chart says spark plugs every 300 hours or annually, whichever comes first. A Vortec 5.7 Indmar/MasterCraft engine takes AC MR43LTS plugs gapped at .045".

Engine Nut


Dumb question...Can I pick these up at a local auto parts shop like NAPA?

east tx skier
03-28-2007, 10:19 AM
Yes, you can.

jraben8
03-28-2007, 10:19 AM
You should be able to though you might have to look around a bit. Not all auto parts stores carry marine plugs all of the time.

east tx skier
03-28-2007, 10:26 AM
You should be able to though you might have to look around a bit. Not all auto parts stores carry marine plugs all of the time.

I didn't think those were marine specific?

mpm32
03-28-2007, 10:29 AM
The only difference is that the marine plug bodies are made of stainless. The auto ones will work fine if your engine compartment is relatively dry.

east tx skier
03-28-2007, 10:34 AM
Good to know. NAPA should have no problem getting those plugs.

Link (http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=430&OEMPartNum=MR43LTS)

wesgardner
03-29-2007, 02:59 PM
For my motor - it's MR 43 T (I think), the "M" prefix just means "marine", and as you will change your plugs yearly, there will be no difference in using the less expensive automobile cousins. Maybe a little anti-seize on the threads and you're good...

Kevin 89MC
04-01-2007, 11:53 PM
Like so many other things, many different opinions on plug changing frequency. I had the same plugs (Motorcraft) in my boat for at least the 8 years I owned it. I checked a different one each year, and they always looked to be in great shape. We didn't put many hours on it, ~300 hrs in that 8 years. Finally replaced them last year, just because of their age. All looked good, I'll keep them as a spare set!
Good luck!