Smoking

Jerry999

Cadet
Joined
Sep 7, 2018
Messages
14
My 2003 90HP ELPTO Mercury Smokes like crazy on startup (fogs up the boat landing)! Normally will run alright afterwards, but Saturday fouled a plug so wouldn't idle well. Ran okay at speeds. Any help would be appreciated.
 

TrybalRage

Seaman
Joined
Mar 2, 2010
Messages
60
I'm dealing with the same issue, just got a new check valve to add between the oil line and fuel line. Hoping it will help. The oil seems to 'bleed down' into the fuel line, even past the primer bulb when it sits. This means after sitting it's getting way more oil than normal during startup.

Technically this valve is supposed to keep fuel from pumping up into the oil system but I'm hoping it helps this issue as well.

Edit: This guy https://www.crowleymarine.com/parts/8236.cfm
Part #27 in this diagram: https://www.crowleymarine.com/mercury-outboard/parts/3374_80.cfm?mdl=YRD4JF
 
Last edited:

Jerry999

Cadet
Joined
Sep 7, 2018
Messages
14
I hope that helps. From what I have read the oil injection system is supposed to be 80 to1 on idle and 50 to 1 off idle,but I don't see how to adjust it. Mine has a stop on it where the linkage connects but I wouldn't want to make a mistake.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,033
A fouled plug indicates a lack of heat in the cylinder.-------It needs attention.-----Do a compression test.-----The shop manual has a procedure for checking oil pump out put.------If you understand 2 stroke lubrication you will find that more smoke at startup is very normal !!
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,944
My 2003 90HP ELPTO Mercury Smokes like crazy on startup (fogs up the boat landing

Keeps the Mosquitoes away and most 2 stroke oils smell wonderful when burnt, bringing back fond memories
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,286
No smoke would be worse, haha.
Im really not up on your particular engine, but I do know that on some 2 strokes with sequential or throttle proportional variable oil injection...should the actuator or cable controlling the flow of oil snap or fail..the design means the flow is defaulted to full flow for safety.
Perhaos not relevant to your engine but certainly the case on some marine 2 strokes.
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,589
If it was bottom plug that fouled check the seal on rear of oil pump as I have seen these back out and flood lower cylinder with oil.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
Go to WW and get some Pennzoil Premium (syn blend) oil in the sporting goods dept for your engine oil requirements and a few cans of Sea Foam in the auto parts dept for engine hygiene. Initially dump the whole 16 oz can into 10 gallons of gas and after that keep 1 oz per gallon of gas in your fuel or fuel mix if no oil pump. Will clean up your combustion chamber, engine will do little to no smoking and run much better. If you are inclined, Google "Decarb" and do that (best if the neighbors are away on vacation as it's smoky) then run your 1 oz per gallon in every tank.....spoken by a 2004 version of your engine exowner.....gave up fishing and donated it to the local fire station who had to borrow a boat every time they needed one.
 

Jerry999

Cadet
Joined
Sep 7, 2018
Messages
14
It was the bottom plug that fouled, so I will check that. I am using sea foam in my engine, but thanks for the advice.As for the smoking it is excessive and like all of us ,we like to see some smoke from our 2 stroke engines as this tells us that it is being lubricated, but mine is so bad that the boat ramp disappears from view.
Thanks to all who tried to help, and all information is appreciated.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
It was the bottom plug that fouled, so I will check that. I am using sea foam in my engine, but thanks for the advice.As for the smoking it is excessive and like all of us ,we like to see some smoke from our 2 stroke engines as this tells us that it is being lubricated, but mine is so bad that the boat ramp disappears from view.
Thanks to all who tried to help, and all information is appreciated.

".......but mine is so bad that the boat ramp disappears from view." Yepper, that's a malfunction.
 

Jerry999

Cadet
Joined
Sep 7, 2018
Messages
14
Okay I have the carbs on my workbench and they are perfectly clean. There seems to be some slack in the oil pump variable oil injection lever. I don't know if this is normal. Getting up the nerve to remove it now as this isn't in my territory.
35 years as an aircraft Mechanic and a life time of automotive mechanics as a hobby gives me a built in repair whatever it is
attitude.
 

TrybalRage

Seaman
Joined
Mar 2, 2010
Messages
60
Please let me know if the check valve fixes the problem.

Finally got the boat out after changing that check valve and making a very small adjustment to the oil pump lever.

I'm happy to report no more smoke! Almost looks like a 4-stroke on the water, except for the sound. Huge, huge difference.
 
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