Knot 4 Me

How the he!! did you change the number 7 plug? Especially on a twin setup?! I can't even get the boot off as it is trapped between the oil line from the filter pad on the block to the remote housing and the hose from the remote housing to the oil cooler. Even if I could get the boot off there is no way to get the socket on the plug Am I missing something here or were my oil lines routed by a prankster at Merc?!

2003 motor, serial number OM683216.

https://www.mercruiserparts.com/Show...OTE+OIL+SYSTEM

Lines 29 and 28 intersect right over the top of the plug wire boot. The wire itself has just enough room to pass between where the lines intersect but the boot is trapped behind them. I don't see how to change the plug without removing at least the cooler line. Before I do that I want to make sure I'm not missing something obvious to everyone but me!

TIA!

Sydwayz

iTrader: (1)

It's a *****.
First time I did it, 2 hours to change 7 plugs.
Another two hours to change Plug # 7.
(Yes, 8 hour job for twin engines.)

Now I can get both engines done in about 2 hours.

My advice:
1) Lay across the top of your engines, and reach down. Lift your hatch straight up if you need to. This will drastically improve your access. This different leverage will help you with the boot. Put a thick moving blanket across the top of your engines to lay on.
2) Use a 6" extension that has a wobble on the end of it & a 3/8 ratchet that has a hinge joint between the handle and the head.
3) Put the spark plug socket on the plug first...
4) Then put the extension on the spark plug socket once you have the socket on the plug.
5) Use the fuel line trick to put the new plugs back in the block.

It's a real bear the first time you do it. Now that you are going to return to it on attempt two, you will get it.

253

496's are good engines but are a pain to work on, from changing spark plugs to changing a sea water pump they are horribly designed, ,,

Knot 4 Me

Brian, I have fairly decent access as I can lay the upper part of my body in the bilge next to back of the engine. The problem is I cannot reach my fingers around the oil lines to grab the plug wire boot to pull it off. I'm trying to figure out if all 496's are this way or did they route my oil lines differently than most. The lines I reference above cross each other directly over the #7 plug. The wire passes between the lines but there is only enough room for the diameter of the wire. No way the boot can pass between the space between the lines and the lines are pretty much pressed against the end of the boot.

Sydwayz

iTrader: (1)

Mine is really, really tight right there too. I remember having to bend the plug boot as I'm pulling it. It's not my favorite thing to do to a plug wire.
I can tell you this: I've tried several different spark plug boot removal tools, and none of them help. It's too tight. I usually have my thumb and forefinger straddling the oil lines to get it loose.

Wait until you need to pull the block drain plugs for the antifreeze.

Knot 4 Me

Agree on the boot removal tools. Would be of no help in this situation.

I gave up on accessing the block drains a couple seasons ago. Just drain what I can by taking the hose from the water pump to the heat exchanger off and draining out/sucking out what I can. Then refill. Doing this multiple times should get the AF pretty well refreshed.

buck35

Can you access the clamps that hold the lines in place? Then loosen the oil line and reposition it slightly to gain some space.

Sydwayz

iTrader: (1)

FWIW:
18MM socket to with universal on SB side of SB engine.
5/16 internal allen socket for PT side of PT engine.

(Yes, I wrote that down in my book.)

underpsi68

I'm glad a only have a single engine boat. I can change plugs on my 496 in less then 10 minutes. Sorry to rub it in guys.

Sydwayz

iTrader: (1)

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