Do I have the correct Spark Plugs?!?!?

[tdelandsheer]

Went to do some maintenance this year and found out the Spark plugs do not match the Plugs I was told to buy in the Indmar operators manual.  The Manual says to use MR43LTS the boat had MR43T in it. Visually the threads are about a half inch longer on the new LTS.

I did put one in, disconnect the cap and turn the boat over a few times. After the test the plug had no marks like the piston had hit it. I did this same experiment on a second cylinder and got the same results.

I did read some where that the vortex engine could be what makes the difference of which one to use. I do believe I read that on the master craft team talk and im not even sure if vortex was or is a thing for malibu. If vortex makes a difference does anyone know how to tell if i have a vortex (without looking at the type of plug).

I have a 1996 sunsetter VLX with a monsoon 320 and MPI.

Just for the record I do plan to use the NGK equivalent for these.

Does anyone know what spark plugs I need?

Thanks in advance!

[MadMan]

I don't know what year Indmar switched to Vortec (Chevrolet did in '96), but a Vortec use's the LTS plug.  A Vortec can be identified by having only 8 bolts attaching the intake manifold.

P.S. stay off that MasterCraft sight if they are calling them vortex.

[ski40mph]

An engine builder told me vortex engines have valve covers with the bolts running down the middle. That means my 1990 is a vortex. ? I think not.

[tdelandsheer]

2 minutes ago, MadMan said:

I don't know what year Indmar switched to Vortec (Chevrolet did in '96), but a Vortec use's the LTS plug.  A Vortec can be identified by having only 8 bolts attaching the intake manifold.

P.S. stay off that MasterCraft sight if they are calling them vortex.

Yea, "vortex" was my bad spelling. The manifold should work great for identification. Just to help me either get a positive or a negative confirmation would you know how many bolts a non vortec engine would have?

[MadMan]

8 minutes ago, tdelandsheer said:

Yea, "vortex" was my bad spelling. The manifold should work great for identification. Just to help me either get a positive or a negative confirmation would you know how many bolts a non vortec engine would have?

Vortec's will have 2 vertical bolts close to each corner.  Non-vortec's will have angled bolts near the center.

Edited May 15, 2017 by MadMan

[tdelandsheer]

That was so easy to tell I defiantly have a vortec and that means the last owner was using the wrong plugs. New plugs, cap, rotor and wires hopefully this thing runs better this year!

 

Thanks for the information guys I feel confident I have the correct plugs now. Once again 2 hours of reading online wrapped in 5 minutes on this forum.

[Dlow]

 Can anyone help me identify if I need the ACMr43t  or MR43LTS? I have a 99 response I just bought with a 5.7 throttle body EFI. Manual says it’s theMr43t  but the ones I took out were the champion equivalent of LTS. By the sounds of this post I have a vortec engine and should be using the 43LTS but that means the manual is wrong...