To do, or not to do - that is the question... 496 MAG maintenace...

trdehmer

trdehmer

Member
Jul 29, 2009
186
Lake Minnetonka, MN
Boat Info
2003 280 DA
Engines
Single 496 MAG
Getting close to that time of the year when I need to place the boat into storage for the winter. I don't have a trailer, so marina does the work - the less I need to do, the more $ I save!

I do the typical which is flush the engine with RV Antifreeze, flush water and AC system, unplug batteries, change gear lube, stabil, oil/filter, fuel/water separator, grease fittings, fog engine.

Here is what I'm questioning and if it REALLY needs to be done (probably 80-100 hours on engine since 2015 season):
*Grease U-Joints/Engine Coupler (last done 2015 winterization).
*Replace Water Pump Impeller (last done 2015 winterization).
*Tune-up engine (never done, I can change spark plugs myself - but what about plug wires, rotor, distributor cap?). Fuel filter was done a couple years ago.
*Anodes (done this spring before dropping in fresh water lake - there is definitely Anode material still left - but I'm not positive how to detect when they are worn?)

Looking for honest opinions/experience please.
 
See my answers typed in below.

quote:

Here is what I'm questioning and if it REALLY needs to be done (probably 80-100 hours on engine since 2015 season):

*Grease U-Joints/Engine Coupler (last done 2015 winterization). This is an easy job with a grease gun and flexible hose. Lay on the engine and reach in to the assembly and zerk fitting. In our area, most go 5-6 years between pulling drive to grease u joints.

*Replace Water Pump Impeller (last done 2015 winterization). What is your water pressure. We get 5-6 years in freshwater in my area. Pressure reading will be a good litmus test.

*Tune-up engine (never done, I can change spark plugs myself - but what about plug wires, rotor, distributor cap?). Only plugs and wires on 496, no rotor or cap. Easy job and all parts are under $170.

Fuel filter was done a couple years ago. Again, $70 and 20 minutes, simple.

*Anodes (done this spring before dropping in fresh water lake - there is definitely Anode material still left - but I'm not positive how to detect when they are worn?) they need replaced when 40% is gone. Technoseal makes replacements for $55 in magnesium. 30 minute job.


Looking for honest opinions/experience please.
 
Thank you for your response. For the Grease U-Joints/Engine Coupler - doesn't the lower unit need to be removed and boat out of water? If not, how do I find where the zerk fitting(s) are? Any pictures or tutorial available anywhere??

Is there a simple means to determine what my water pressure is??

For the engine Tune-up, where do I get replacement spark plug wires that are not nearly as expensive as the OEM ones and are just as good - does someone have the parts numbers? Once changing spark plugs and plug wires, how important is it to have the Ignition Timing checked/set?

How often should the main fuel filter be changed?
 
trdehmer said:
Thank you for your response. For the Grease U-Joints/Engine Coupler - doesn't the lower unit need to be removed and boat out of water? If not, how do I find where the zerk fitting(s) are? Any pictures or tutorial available anywhere??

Is there a simple means to determine what my water pressure is??

For the engine Tune-up, where do I get replacement spark plug wires that are not nearly as expensive as the OEM ones and are just as good - does someone have the parts numbers? Once changing spark plugs and plug wires, how important is it to have the Ignition Timing checked/set?

How often should the main fuel filter be changed?
Click to expand...

Drive does not need pulled to grease the coupler. There is a zerk fitting on the drive shaft on the inside transom assembly - you will readily see it when you can look back there. I have not had a boat yet where I couldn't get at it. Really as simple as getting your eyes on it.

Get plugs from Advance Auto, Rock Auto, etc. ~$6 each (NGK TR55IX or AC Delco 41-993). Use Volvo Penta wires for $105 (#3861295). No timing to check - computer controlled.

If you have Smartcraft, it will display pressure. If not, a fitting and pressure gauge can be installed into the power steering cooler in minutes. need a 0-25PSI range gauge.

I change the fuel filters every other year (100 hours use). Opinions vary.
 
Is there a special grease I need to use on that zerk fitting for the coupler? I have a Marine Boat Trailer & Marine Equipment/bearing grease cartridge in my grease gun.

For the plug wires, for the OEM ones, it has two different types of wires depending on what piston/firing location (guessing its based on length?). Will those Volvo wires work for all 8 plugs?
 
trdehmer said:
Is there a special grease I need to use on that zerk fitting for the coupler? I have a Marine Boat Trailer & Marine Equipment/bearing grease cartridge in my grease gun.
Click to expand...

That will work, Mercruiser recommends their Quicksilver Extreme grease. I used the blue Lubrimatic marine grease and the Quicksilver grease, cannot tell a difference. Main thing is to grease it.
 
Yes, I have the Volvo wires on mine right now.
 
I changed spark plugs, greased the zerk for the coupler, and cleaned out the heat exchanger last night. I'm guessing it was 5 years ago since I last changed the spark plugs. Not gonna like, the plugs looked to be in real good shape still with good "burn" characteristics (not too lean, not too rich). Even though changing the plug wires doesn't appear to be too difficult, w/o any run-ability issues I'm not sure I can justify the time/$....
 
If it ain't broke don't fix it. Just remember that it probably wont brake at the dock, most likely its gonna brake in the middle of the most spectacular days of summer with a boat load of guests.
 
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