Merc 40HP idle problems

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REELFISHERMAN

Cadet
Joined
Nov 25, 2002
Messages
12
My 2002 Merc 40HP idles very rough. It sounds like it is occassional hitting on one cylinder.It has been this way since I purchased it new. I have replaced the plugs and adjusted the idle. The engine idle is 1000 RPM. The engine runs great above idle. The engine also smokes excessively sometimes at idle. <br />When I purchased the motor new, a dealer rebuilt the carb within a month of purchase saying that there was dirt in the carb. Merc would not warranty the work. Latter, a magnet came loose in the flywheel and wipped out the magneto ect. <br /> Any help will be appreciated.
 
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FlyBoyMark

Ensign
Joined
Apr 14, 2002
Messages
934
Re: Merc 40HP idle problems

Oooow Boy! Is this the 2 or 3 cylinder. I surmise its a 2 cycle because of smoke. Did the Mercury dealer tune and adjust the engine before you took it? This IS REQUIRED by ALL Mercury dealers for ALL new Mercury outboards. They are NOT allowed to sell "in the box" anymore. There is a filter in the fuel system BEFORE the carbs on the engine..whats crude doing in the carb on a new engine? Didja use an old tank? Part of "Pre Sales Service" is to CHECK the calibration of the oil injection pump. Are you still using extra oil (break-in) in the fuel in additon to the oil in the engine oil injection tank? Sounds like you might need to change to a new service dealer. Do a compression check on this engine ASAP an get back...
 
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2springers26

Seaman
Joined
May 18, 2004
Messages
63
Re: Merc 40HP idle problems

you need to find a new service rep.... You need to See If all cyls have spark... with cdm Ign.. It's not like the old days... Grounds are very important to the cdm.... Just because you have spark @ cranking does Not mean it Is Firing when running... a simple test For ign or fuel... when the problem occurs.. spray a LITTLE fuel or carb cleaner in the carbs one @ a time to see if tha cyl Is lacking fuel... that should point you more tward your problem
 
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REELFISHERMAN

Cadet
Joined
Nov 25, 2002
Messages
12
Re: Merc 40HP idle problems

Thanks, actually it is a two cylinder 2 cycle motor. I purchased the motor and boat as a package from a Tracker dealer. Just after I purchased the combo the dealer went out of business. I was forced to take the boat to another dealer for the idleing problem as well as other motor problems. It has been a nightmare, Tracker would not help me I purchased the combo in March 26, 2002 and the first time that I took the boat out was the first week in April when the problems surfaced. Tracker said it was Mercury's problem not theirs eventhough their dealer went out of business. The customer rep at Mercury was downright nasty,uncomporative,and unconcerning, needless to say, I doubt that I will ever purchase a Mercury again or a Tracker product.
 
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FlyBoyMark

Ensign
Joined
Apr 14, 2002
Messages
934
Re: Merc 40HP idle problems

I'm sorry that you had a bad experince...Mercury is usually very good about waranty stuff. My 40 HP was about 2 months out of warranty and they fixed a "known" problem that would have cost me 800.00 bucks to fix for free. During production. many 3 cylinder 2 cycle forties and fifties had the wires cinched too tightly at the bullet connectors and they eventually shorted through the insulation because of the sharp corners on the crimps. This fried the whole charging system and burnt all the wires on many motors...I surmise most of your problems surround the particular dealer you dealt with. Tracker does offer good service, BUT the outboards are the responisbility of the outboard manufacturer. Like springer and I said.....find a service center that does service and not boat sales. This type of selection guarrentees somebody who is sevice oriented and not jus pushing boats to make a buck. They WANT the warrenty work 'cause Mercury pays them for it...and its thier bread and butter....Be prepared to document these problems before your warranty expired...
 
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Safe Side/CC

Cadet
Joined
May 15, 2004
Messages
6
Re: Merc 40HP idle problems

Had the same issue w/ my 115 Merc. Dealer went all over it & couldn't find then another found that a ground wire had come loose so one of the cylinders wasn't firing. He said there's a ground wire for each cylinder and only one was loose.
 
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REELFISHERMAN

Cadet
Joined
Nov 25, 2002
Messages
12
Re: Merc 40HP idle problems

Thanks for everyones help. I have removed cleaned the carb, cleaned the fuel filter and installed new spark plugs. None of this helped.<br /> I checked with my Clymer's manual and they indicated that a malfuncting fuel bleed system can cause stalling or missing at idle and excessive smoke on acceleration.<br /> My 40hp Merc is a two cylinder model. Are the removal of the check valves difficult? The manual shows only one check valve, that I can see, that appears to be behind the reel valve assembly.<br /> Thanks again for your advice.
 
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mtelow

Recruit
Joined
Jul 17, 2004
Messages
3
Re: Merc 40HP idle problems

Did you ever have any luck fixing the problem? We have a 2001 Merc 40HP 2 stroke, 2 cylinder, 1 carb. that has the same problem. Merc. mechanic says this is just the way they are. We have done everything you have with no luck either.<br />
Originally posted by REELFISHERMAN:<br /> Thanks for everyones help. I have removed cleaned the carb, cleaned the fuel filter and installed new spark plugs. None of this helped.<br /> I checked with my Clymer's manual and they indicated that a malfuncting fuel bleed system can cause stalling or missing at idle and excessive smoke on acceleration.<br /> My 40hp Merc is a two cylinder model. Are the removal of the check valves difficult? The manual shows only one check valve, that I can see, that appears to be behind the reel valve assembly.<br /> Thanks again for your advice.
Click to expand...
 
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REELFISHERMAN

Cadet
Joined
Nov 25, 2002
Messages
12
Re: Merc 40HP idle problems

Originally posted by REELFISHERMAN:<br /> Thanks for everyones help. I have removed cleaned the carb, cleaned the fuel filter and installed new spark plugs. None of this helped.<br /> I checked with my Clymer's manual and they indicated that a malfuncting fuel bleed system can cause stalling or missing at idle and excessive smoke on acceleration.<br /> My 40hp Merc is a two cylinder model. Are the removal of the check valves difficult? The manual shows only one check valve, that I can see, that appears to be behind the reel valve assembly.<br /> Thanks again for your advice.
Click to expand...
 
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kergoat

Cadet
Joined
Aug 22, 2005
Messages
22
Re: Merc 40HP idle problems

hello<br />roland french user, i ve exactly the same pb on my mercury 40 hp 2 cyl 2001 in idle the power vibrates to much.<br /><br />engine run great above 2000 tr/mn !<br /><br />i clean the idle part of the carb<br />ajust idle/ idle screw mixture (1.5 tr)<br />adjust timing of 8 degré to 800 tr/mn via link rod<br /><br />i ve also this idles very rough like sometimes one cylinder missfiring !<br /><br />Is there someone who fix this problem ?
 
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kergoat

Cadet
Joined
Aug 22, 2005
Messages
22
Re: Merc 40HP idle problems

Reelfisherman Do you change the check valves ?<br /><br />tks
 
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