[v-tim]

For those, the ikey factor is compression pressure, lower, open the gap, higher, tighten it up.

[ritobanb]

I have 4,454's.
I have never been able to find the correct gap for the plugs.
I get a different gap from different sources!
I asked at O'Reilley's the other day and was told .035
Other times it's .045
Once it was .060
The engine I'm putting new a/c plugs in now is a 1986,454 from a motorhome.It's completely stock with the RV cam.H.E.I. with 350 trans and the car is blue!
What's Ya'lls best guess?
Thanks,Mike.

[altamic]

Edited by grumpyvette on 08-27-16 05:31 PM. Reason for edit: No reason given.

[John Doe]

Age: 73
Loc: FLORIDA USA
Reg: 03-16-01

[Stephen Gornick]

Lol!!
Although I'd normally agree. I'm willing to bet that if I just walked around my "neighborhood" and pulled the ignition wire off the mowers/blowers/tillers/tractors and weed whackers I'd find the dreaded "C" word written on 90% of the plugs! here

[PureIt]

Re: Spark Plug Choice - Mercruiser 7.4 LX MPI [links]

[FreedomFirst]

When I moved down here, the place I worked at carried the full line of NGK, but not AC. So guess what we used.

[Frost987]

Like the guys above, I use NGK. Easier to get locally for me too. more

[Gavin Andresen]

Re: Spark Plug Choice - Mercruiser 7.4 LX MPI

[jackkalis58]

Mercruiser 7.4 engines are V-8 and have a displacement of 7.4 liters. Maximum revolutions per minute is 4,200 to 4,600 rpm. Idle rate is 600 rpm in neutral. The eight cylinders fire in a 1-8-4-3-6-5-7-2 sequence. The 7.4 multiport injection model has 310 propshaft hp and 231 propshaft kilowatts. The 454 Mag multiport injection model has 385 propshaft hp and 287 propshaft kilowatts.

[kenjo]

Oil pressure should be 30 to 70 pounds per square inch at an rpm of 2,000 and a minimum of 4 PSI when the engine is idling. Thermostat should be at 160 degrees Fahrenheit. more

[inertia]

Mercruiser 7.4 engines are on the large end of the Mercruiser engine line. Mercruiser engines are made for the marine market by Mercury Marine. The 7.4L models are the 7.4 MPI and the 454 Mag MPI. more

[Loki]

The Mercruiser has a 12-volt battery. Operating amps when cold are 65 amps and when hot, 72 amps.

[Shfork]

[hatice23]

Spark Plug Wires Chevy Message Forum Restoration And Repair Help

[PLATO]

Diagram Wiring For Motorhome Full Version Hd Quality Mediagrame Antichemurasoro It more

[tommy]

How To Replace Your Mercruiser Spark Plug Wires With Pictures more

[helen123]

1989 Chevy S10 Engine Wiring Diagram 155 Athletics

[Ensayia]

Need Firing Order Ona 454 Chevy Engine Or Plug For Each Sid Of Distributer 2000 Truck Flat Top

[Julia Darner]

Gm Full Size Trucks 1988 1998 Wiring Diagrams Repair Guide Autozone [links]