Pontoon Boat & Deck Boat Forum

Just did the first oil change on my new to me 2006 Merc 90 4-stroke. Very clean, well taken care of engine.
I'm not a novice to mechanics by any means either and always feel its best to check informational sources before attempting something for the first time. So I did just that and from what I found, it seems that most sources are VERY particular about getting the oil volume in the crosshatch area of the dipstick. Not the top, not the bottom, but within the area.

Now that said, I know most people are fearful of running ANY amount of oil over the crosshatch in their engines (cars, trucks, etc.) so I understand the heeding, but the level of concern I was hearing was seemingly high during my research.

Reading the manual, the engine calls for 4.8 quarts capacity. I checked the level prior to draining and it was just about to the top of the crosshatch. So I drained what was in there and came up with 4 quarts. Then I replaced as per the manual (4.8 qts) only to find the oil is now well above the crosshatch. Hmmm..... Whats the deal? I didnt overfill since I used the amount specified by the manual, but clearly it seems somethings not right.

So I'm curious as to how many others run into this problem? Since I'm running the specified volume, I'm apt to leave it as it is and run it. Could the dipstick be wrong? Do most people really pay attention to whether or not their oil level is "within" the crosshatch or do they fill and go? Thanks everyone.

It's 4.8 ots with a filter change and I failed to see mention of a filter anywhere in the post.

On my motor prior to draining the oil, it's important to raise the motor as high as possible for 30 seconds or so, and then drop it all the way down. It gets as much oil as possible out of the motor by using this technique.

I too agree about trying to get the oil level at halfway on the crosshatch pattern. 4 stroke outboards run so cool that it's hard to get them hot enough (when new) to completely break in the piston rings. Unless the engines are completely broken in, there may be some gasoline get past the rings and mix in with the oil--and the contaminated oil level will rise on the dip stick. Many of the earlier large Yamaha SHO motors were especially susceptible to "making oil."

By only putting enough oil to show 1/2 way on the dipstick, you can easily monitor your motor's oil level. And it's best to check the oil level every time you use the boat.

Yes, I followed the proper procedure of raising the motor as I understand you're not supposed to have them in the "run" position during the oil change.

And yes, I changed the filter as well.

But no, its not making oil either since I've only run the engine for about 5 minutes after filling to assure no leaks and everything was OK. After that did I find the oil level was higher than the crosshatch.

So again, I completely understand why overfilling can be a problem but my curiosity is more to why the manual calls for 4.8 if its going to cause an overfill situation.....

It's nice to have one of the pumps to change oil with--so you can suck out a little oil if the level is a little high.

When doing maintenance, I first dump my lower unit grease into a Walmart plastic kiddy swimming pool watching for water intrusion and metal shavings. Then I dump the motor oil on top. There's not problem getting oil on the driveway with the pool.

I'd hate to pay a dealer $300 for a job I can do in 30 minutes for $45 in supplies.

I have a 2007 Merc 90 and it's capacity is 5.2 qts. I drained the oil for the first time (just got the boat) and my first issue was after pulling the plug, the oil shot out about 4' and overshot my oil pan! I tried compensating but never thought it would shoot out that far! So, after cleaning up the splattered oil all over the driveway, I changed the filter and put in 5.2 quarts and it was perfect. I also saw it had the 5.2 qts listed right by the oil filler cap.

I used a 5 gal bucket and seemed to catch everything..... Still a pain but I was able to get the job done with very little cleanup.

Anyways, I decided to drain some oil out since everyone/everywhere was adamant about not getting the oil higher than the crosshatch. So I let out about a quart and the level now sits just about the top of the crosshatch. The only conclusion I can come up with is that unknowingly I didnt get all the old oil out. Next time I guess I'll have to work at moving the motor up and down better to see if I can get more trapped oil to drain out.

My understanding is the Yamaha sump is cone shaped and can greatly change the oils level on the dipstick based on the position of the motor. Not sure if the Merc's are like that too.

[quote="katoom"]I used a 5 gal bucket and seemed to catch everything..... Still a pain but I was able to get the job done with very little cleanup.

Anyways, I decided to drain some oil out since everyone/everywhere was adamant about not getting the oil higher than the crosshatch. So I let out about a quart and the level now sits just about the top of the crosshatch. The only conclusion I can come up with is that unknowingly I didnt get all the old oil out. Next time I guess I'll have to work at moving the motor up and down better to see if I can get more trapped oil to drain out.

My understanding is the Yamaha sump is cone shaped and can greatly change the oils level on the dipstick based on the position of the motor. Not sure if the Merc's are like that too.[/quote]

Probably because, for many years; Yamaha was the source for Mercury's four stroke outboards, like Suzuki was for OMC.

I just did my 2015 90HP four stroke and it took 5.5 quarts with filter change. Oil is 3/4 on the crosshatch. Need to do the lower unit next.

Mike

[quote="mzodarg"]I just did my 2015 90HP four stroke and it took 5.5 quarts with filter change. Oil is 3/4 on the crosshatch. Need to do the lower unit next.

Mike[/quote]

After toasting a lower unit on an old motor for a lack of maintenance, I think the lower unit's more important to change grease in than oil changes on the engine. And it's well worth investing in a pump as you can get by buying 1 qt. of lower unit grease using a pump.

My problem is Yamaha has tiny paper gaskets ($1) that I never seem to have on hand, and no local Yamaha dealer to buy'em from.