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oil level in 2009 Mercury 9.9 4 stroke (and smoke)

T

troutguy

New member
This is a dumb question which I am known for, but just bought it with a boat, and I don't have a manual yet, and want to use it again before I get one. The question: How do you check the oil level in this engine? Do you put the dipstick fully in, or stop when it hits the rubber-like boots on the stick? (the reason for this question, besides just a reasonable maintenance check, is that I have observed quite a bit of smoke coming from the area of the exhaust when starting it in a water-tank, and some smoke when going from trolling rpms to higher rpms). I trolled about 2-3 hours with it a few days ago and it trolled fine, maybe a little fast, but did observe the smoke both when starting and some smoke when changing from trolling to higher speeds. Also a little hesitation when changing from trolling to higher speeds. Then it sat around partially tilted -- on the boat's transom, of course -- for a couple of days; and today I lowered it to the vertical position and started it in a garbage-can tank. It started on the first pull, but I observed quite a lot of the smoke upon initial starting). As a first step, I want to be sure it is not overfilled with oil. Assuming the oil level is OK, what should be the next diagnostic step? (Note that when I first got the rig last weekend, I fogged the cylinders with ONAN generator fogging oil and let it sit awhile before starting).
 
Today I found out that if I stopped the dipstick at the first contact with the rubber boot on it, then the oil level read full. Searching the internet revealed that one should put the dipstick fully in (can someone who has a manual check this?) when reading the level. Someone may not have known how to read the oil level.

Since the rubber boot is roughly 2 inches long, this means the engine may have been overfilled by 2 inches. I'll lower the level and see if it helps, and keep you posted.

Would it hurt for the Mfg to put a label somewhere that shows how to measure the oil level? I have other types of machinery that do this.
 
Since I was here for another question I thought I would update this one. I drained the oil from the engine into a measuring jar and found that there was about 33-34 ounces, a little over a quart. Since the manual only called for 27 or 28 (can't remember exactly) I assumed that overfilling was the problem, probably caused by the confusion over whether the dipstick should be inserted to just the rubber boot, or "full in", for the oil level measurement. After I drained and refilled it to the required amount I started it in a test tank and it smoked for a little while, then cleared up and thereafter appeared to be operating normally (i.e., no smoke, even when revved up from a slow rate). I think maybe the reason for the initial smoke was that to drain the oil, I tilted the motor full up, which probably let some more of the excess oil into the cylinders. So, pending how it acts on my next fishing trip, I think the smoking problem might be solved. Will try to remember to post the final results after my trip.
 
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