Oil change - How's it done on I/O small block?

[tmh]

A couple questions. I have no owners manual for my 1985 Mark Twain 19' Bow Rider so i count on you smart guys! Mercruiser 5.0L, V8, 305 engine (I think)

First, how does one go about changing the oil for an I/O engine? Is it all done in the engine compartment? Is there a drain plug like on a car engine? Any special tools to reach hard to get bolts, etc?

How much oil would my engine take?

Lastly, I've used an oil system "clean-up" product called Auto-RX on two cars with older engines. I thought it might be a scam foo-foo dust product but it is legit. I couldn't believe how much better those older engines ran after the cleaning cycle. It is for older or neglected engines that may be building up some sludge or hot spots.

After adding it to the oil, you run the car for 2,000 mi. then change oil, run 2,000 more and then change again. How much boat engine usage might one estimate equals about 2,000mi. of car driving? Just a rough guess is fine.

btw, i do NOT want to argue the merits of Auto-RX....I've done that in an auto forum and realize most can not believe such a product really cleans up the engine. Not trying to convince anyone, just looking for some good info on how I can apply it to my boat engine.

IF you're interested, i thin their website is auto-rx.com

Thanks as always.

 

[bjcsc]

Re: Oil change - How's it done on I/O small block?

A couple questions. I have no owners manual for my 1985 Mark Twain 19' Bow Rider so i count on you smart guys! Mercruiser 5.0L, V8, 305 engine (I think)

You need to get one. They are invaluable. There is much more to do than change your oil.

First, how does one go about changing the oil for an I/O engine? Is it all done in the engine compartment? Is there a drain plug like on a car engine? Any special tools to reach hard to get bolts, etc?

It is done in the engine compartment and there is a drain plug just like on a car oil pan - but you can't get to it. You suck it out through the dipstick tube with either an electric or manual pump.

How much oil would my engine take?

4-5qts depending on how much you get out.

I thought it might be a scam foo-foo dust product but it is legit.

Now that is funny...

 

[Gary H NC]

Re: Oil change - How's it done on I/O small block?

Pump the oil out thru the dipstick tube. all that oil in the bilge will take forever to clean up.
Does your dipstick tube have threads on the end the size of a water faucet? If it does you can get a cheap Balkamp drill pump from Napa,it works great.
Warm you oil up first or it will take forever to get it out...
Also you could get an oil change adaptor kit that will screw in where the drain plug is on the pan.It has a hose that will go out the water drain hole on the back of the transom..

 

[stevieray]

Re: Oil change - How's it done on I/O small block?

tmh - getting the oil filter out can be tricky depending on how your engine compartment is set up since you will most likely be working blind. On mine, I can slip one of those flat plastic microwave dinner pans (empty of course) under the area of the filter to catch the inevitable few ounces that leak out when you take it off. Or one of those oil-absorbant pads will work too.

 

[tmh]

Re: Oil change - How's it done on I/O small block?

Thanks guys. Good info.....enough to let me know I won't be doing this myself. With today's gas prices, what's anothe $100 for an oil change (no idea how much it costs, but $100 better cover it!).