40 Mercury Smoking

[Marshgoat]

I have a 1999 40 Mercury 2 stroke 3 cylinder that starts and runs great. This past weekend I had a family emergency and had to run wide open (5500rpms)to the landing for 15mins. The guy running behind me said my motor was smoking quite a bit while running. I pulled the plugs and they are a little wet but the electrodes are nice and tan. I have the service manual for the engine and have timed it, synched the carbs and oil injection pump and have good even compression on all 3 cylinders. No mods, bone stock on an 18x48 1/8in alum flat. Burning Mercury oil only. Motor runs great and doesn't give any problems. Never noticed the smoke before, and it cleared up while idling at the landing. Anyone have any thoughts or recommendations on what I can check ??????

[jmarine]

Possibly steam coming from the exhaust if the water temp was cool or your water pump is not pumping good water at high speeds

[CajunChristian]

Yes, check into getting that oil injection removed before you have to buy a powerhead. I have never kept an outboard past the warranty period without removing the oil injection. If I mix it, I know there's oil in the fuel.
It's very easy to remove, BUT, make sure whoever removes it knows what they're doing. DO NOT leave any of the oil lines to and from the oil pump open. It will cause the bottom cylinder to run lean, again you will be buying a powerhead.
As for excessive smoke, you first have to determine if it's smoke or steam. Could be steam from the water outflow from the engine. Your oil injection could be out of adjustment and the pump is dumping too much oil to the motor at WOT, another reason to remove it. Mercury sells a kit with an aluminum plate and gasket to cover the oil pump drive hole in the block.
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[meaux fishing]

Originally Posted by CajunChristian

Yes, check into getting that oil injection removed before you have to buy a powerhead. I have never kept an outboard past the warranty period without removing the oil injection. If I mix it, I know there's oil in the fuel.
It's very easy to remove, BUT, make sure whoever removes it knows what they're doing. DO NOT leave any of the oil lines to and from the oil pump open. It will cause the bottom cylinder to run lean, again you will be buying a powerhead.
As for excessive smoke, you first have to determine if it's smoke or steam. Could be steam from the water outflow from the engine. Your oil injection could be out of adjustment and the pump is dumping too much oil to the motor at WOT, another reason to remove it. Mercury sells a kit with an aluminum plate and gasket to cover the oil pump drive hole in the block.
D

Very good advise. I burnt up a merc at dark halfway between the lake and 210. I was Lucky that another boat passed me and towed me back

[troy001]

i have a 40 hp tohatsu 2004 model how would i have to go about to remove the oil injection system

[CajunChristian]

Originally Posted by troy001

i have a 40 hp tohatsu 2004 model how would i have to go about to remove the oil injection system

I'm not trying to be a smarta$$, but if you have to ask, get someone qualified to do it. Is it worth saving a few dollars to possibly toast your motor?
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[troy001]

well i am ase master certified on heavy duty diesel just wanted to know if you had to remove the oil pump or leave it on and just block oil lines

[CajunChristian]

Originally Posted by troy001

well i am ase master certified on heavy duty diesel just wanted to know if you had to remove the oil pump or leave it on and just block oil lines

I remove every hint of the oil system, lines, check valves, pump, drive gear, bushing, all of it.
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[Andy C]

Originally Posted by troy001

i have a 40 hp tohatsu 2004 model how would i have to go about to remove the oil injection system

Not as important on tohatsu as they are gear driven like a Yamaha, not a vacuum system like merc has.

[CajunChristian]

The 40/50/60 Merc is a gear driven oil system, not a vacuum driven system. So it is every bit as important on Tohatsu's. A leak in an oil line causes a catastrophic failure regardless of brand.

http://www.crowleymarine.com/mercury.../11493_110.cfm

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[troy001]

thanks guys

[Marshgoat]

Thanks for the advice guys. In your opinion what is the biggest danger, the pump itself failing or an oil line breaking? I've researched a little and it appears some people have had Mercury oil pumps fail due to a plastic gear or bushing in the pump coming apart. Not sure if a 99 model would have plastic or not???. I guess you can tell I would prefer to keep the injection system but I also don't want to ruin a powerhead. Boat has a permanent fuel tank built as a step up to the front deck, I switch back and forth to a surface drive a couple times in a year so premixing fuel will be a little pain in the @#% every time I switch back to the Prodrive.

[Andy C]

Originally Posted by CajunChristian

The 40/50/60 Merc is a gear driven oil system, not a vacuum driven system. So it is every bit as important on Tohatsu's. A leak in an oil line causes a catastrophic failure regardless of brand.

http://www.crowleymarine.com/mercury.../11493_110.cfm

D

That's my bad,thanks for the correction
all the mercs I have had were vac.
sorry for the miss info

[CajunChristian]

Originally Posted by Marshgoat

Thanks for the advice guys. In your opinion what is the biggest danger, the pump itself failing or an oil line breaking? I've researched a little and it appears some people have had Mercury oil pumps fail due to a plastic gear or bushing in the pump coming apart. Not sure if a 99 model would have plastic or not???. I guess you can tell I would prefer to keep the injection system but I also don't want to ruin a powerhead. Boat has a permanent fuel tank built as a step up to the front deck, I switch back and forth to a surface drive a couple times in a year so premixing fuel will be a little pain in the @#% every time I switch back to the Prodrive.

I have never seen a 40/50/60 Merc oil pump fail. It's usually a pinhole in one of the oil lines that gets you. The larger Mercs have a nylon drive gear on their pumps, the 40/50/60 has a metal drive gear.
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[Marshgoat]

At the very least, I am changing all the lines ASAP. Thanks for all the advice and reply's. Much appreciated.

[CajunChristian]

Originally Posted by Marshgoat

At the very least, I am changing all the lines ASAP. Thanks for all the advice and reply's. Much appreciated.

Make sure you bleed ALL of the air out of the new lines. If you vaporlock the pump, kaboom, grenade powerhead.
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[meaux fishing]

Originally Posted by CajunChristian

I have never seen a 40/50/60 Merc oil pump fail. It's usually a pinhole in one of the oil lines that gets you. The larger Mercs have a nylon drive gear on their pumps, the 40/50/60 has a metal drive gear.
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yeah mine was the 125