Looking for the right spark

[Colosupra]

Hello everyone,

This is my first post I just bought a 1991 ts6m comp I was told it has a Ford 351. I'm very excited about the boat and I want to keep up the maintance as best I can but I'm not sure about the engine I have. The owner's manual called for a spark plug that was'nt even close to the one that was in the block. I was at a auto parts store do I need to find a marine engine store? I also need to replace the spark plug wires but I'm not sure where to find them or do I need to buy the best Ford spark plug wires I can find and then cut them down to fit.

Thanks for any help......

[riveredge]

Autolite 24's would be an appropriate plug for that engine, which is definitely a 351 unless someone swapped out the original engine. Check out skidim.com - 'electrical and tune-up' and you'll find the wires there too. But there's nothing special about the parts there, you can go to any auto parts store and get plugs and wires for that. The people at Discount Inboard Marine are nice and helpful if you call them, and you can get everything in one place, that's the only real advantage.

[DKJBama92Mariah]

Congrats ColoSupra and welcome to the forum!

If the distributor is at the front of the engine, it's a ford. At the back, a chevy.

Since it's a 1991, there are a few more questions to determine exactly which model 351 you have.

1. Does it have an actual distibutor or does it have a module with coil packs at the back of the engine? If you have the coil packs, then you have the PCM pro tec ignition system. When it works, its great, but if part of the system fails, you have to retrofit a distributor to the engine because parts are no longer available. skidim.com stocks a kit for this purpose. But if it works, leave it alone. The reason i ask is that with a standard ignition, the plugs should be gapped to .035" and on the Pro tec system, they should be gapped at .045"

If you have a standard distributor, the correct wires are: http://www.skidim.com/prodinfo.asp?number=RA121008-9
If you have the protec ignition, the correct wires are: http://www.skidim.com/prodinfo.asp?number=RA121040

2. We also need to figure out if you have a standard or HO 351. If you look at the back of the heads there will be a number of lines cast into the head: 1, 2, or 3. If the head has one or two lines, you have the standard motor which requires Autoline #24 plugs http://www.skidim.com/prodinfo.asp?number=RP030002

If the head has three lines, you're in luck and have the High Output 285 HP version. This version requires Autolite #764. http://www.skidim.com/prodinfo.asp?number=RP030007

With regards to discount inboard marine www.skidim.com , all i can say is that they rock. Their prices are very competitive, and they have great service. I would really avoid buying plugs at the auto parts store. Too much chance the guy could give you the wrong part and cause some damage. $24 for 8 plugs from skidim is worth it I think just for the sake of knowing for sure that you have the right part.

I you are going to place an order with skidim, i would also suggest going ahead and purhcasing a new raw water pump impeller. Even if the old one looks ok, it cheap insurance to go ahead and change it and keep the old one on board as a spare. http://www.skidim.com/prodinfo.asp?number=RP061015

While you're getting her ready for the season, i would also suggest changing the engine oil and filter as well as the transmission fluid. Also let us know what color your transmission fluid is. PCM origanally recommed SAE 20 engine oil for the tranny, but changed their recommendation a coupla years ago to use Dexron ATF. Let us know the color and i'll elaborate some more.

Feel free to fire away with more questions about your new toy. We're all here because we love our boats and we get enjoyment out of helping others enjoy their own Supras.

Welcome again,
DKJ