9.9 Merc Oily Foam from prop

[fish56]

I have a 1986 Mercury 9.9 2-stroke that I had not started up in at least two years. Couldn't remember if I ran the gas out of the carb when I last shut it down.
Anyway, I hooked it up to a relatively fresh tank of gas this afternoon and started it up. Nothing unusual at first, but then I noticed some foamy, greyish, oil droplets in the can of water I was running the engine in. After I stopped the motor, this time running the carb dry, I emptied the can and when I looked at the motor, there was the same greyish brown, oiley foam apparently coming from the prop exhaust and around the prop itself.
I removed the lower end oil drain plug and the oil looks fine, not milky at all and no water showing.

So can someone tell me what this foam is? I'm planning on getting back into fishing this next year and want to get my gear ready ahead of time.

Thanks!!!

 

[JUSTINTIME]

Re: 9.9 Merc Oily Foam from prop

could be fogging oil

 

[fish56]

Re: 9.9 Merc Oily Foam from prop

I suppose that's possible, although I don't remember that I had fogged the motor back two years ago. Geez, I'd better start attaching tags to remind myself. I think I'm going to run the engine again, long enough to verify the problem is still there or maybe verify the oil is out.
I'll check it out soon. I hear the temps are going to drop drastically by mid next week.
Thanks

 

[gss036]

Re: 9.9 Merc Oily Foam from prop

Mix some SeaFoam w/gas and then run, it will clean things up a bit and stablilize the gas some.

 

[fish56]

Re: 9.9 Merc Oily Foam from prop

I'll have to try that, thanks. I haven't heard of the product, but I'm sure the local boating supplier will have it. Probably pick it up tomorrow. I do currently have a spraycan of outboard tuner, I think it's called, made by Mercury marine, but I've never used it. Maybe designed to do the same thing? Not sure.

Thanks for the replies

 

[JUSTINTIME]

Re: 9.9 Merc Oily Foam from prop

that is what ur see in the tank, outboard tuner probally

 

[fish56]

Re: 9.9 Merc Oily Foam from prop

One other issue I noticed with the motor.....while running, besides the normal exhaust through the prop and out through the small port on the top rear of the lower end, I saw some exhaust coming out where the gear shift rod enters the lower end. I would think that may be normal, but have never before paid any attention to it.

 

[JUSTINTIME]

Re: 9.9 Merc Oily Foam from prop

u might need a gasekt where the powerhead meats the midsection

 

[fish56]

Re: 9.9 Merc Oily Foam from prop

Guess I'll have to get a "exploded" view partslist and then do some disassembly and repair.
I don't fully understand the thru the prop exhaust, how the exhaust is routed from the powerhead through the lower end housing and such.

 

[tashasdaddy]

Re: 9.9 Merc Oily Foam from prop

while you are at it change the impeller. after sitting they get hard and are 99% guaranteed to fail. has this engine ever been decarbed. the engine builds up a residue, and running it in the barrel you are trapping it, so you notice it, where on the water you don't notice.

decarb
http://outdoorsbest.zeroforum.com/zerothread?id=2589

 

[fish56]

Re: 9.9 Merc Oily Foam from prop

Thanks T-daddy,
That's an excellent topic from that site about decarbing the motor. I put it into my favorites and will be trying it out on the 9.9. I'll also change out the waterpump impeller as suggested, even though it seemed to work very well when I ran the motor Friday.

 

[Moody Blue]

Re: 9.9 Merc Oily Foam from prop

had exactly the same symptoms 2 summers ago on my 9.9 Evinrude and most everyone (including some here on iboats) told me it was normal, even thought the motor never exhibited this sort of thing before.
I removed the powerhead and replaced the lower crankshaft seals, exhaust cover gaskets and powerhead-midsection gasket. Put it back together and no sign of the said oily foam after that and its run 1 1/2 seasons now. There was no obvious signs of failure when I removed the old parts but obviously something had failed.

 

[WillyBWright]

Re: 9.9 Merc Oily Foam from prop

Now you know why carbureted 2-strokes are being eliminated. Imagine all that crud entering our waterways from the millions of boats we run with them. They're dirty motors! Run a 4-stroke in the same barrel and the water will stay clean for a very long time. What you are describing sounds pretty normal to me. I like the impeller advice.