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I have a 1985 V4 120hp outboard motor that does not want to…

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I have a 1985 V4...

I have a 1985 V4 120hp johnson outboard motor that does not want to idle, the carbs have been completly cleaned and rebuilt. whole motor lubed and everything. I am getting a lean pop on idle at random times and will cut off. Motor will run smooth at higher RPMs but can not slow idle. What is the problem?

The following below is what the mechanic performed on the motor:



Drain/Fill



drain/fill



fix



Motor not


Gaskets 439078 Carb Repair Kit Ay 332319 Gasket Checkout:good ignition, cold compression test performed 1)130 2)135 3) 133 4) 132, R & R propeller, greased prop shaft, lower unit with new lube, installed new drain/fill gaskets, gear  lube dark" may need to be changed more often, customer installed new spark plugs, customer inslalled new water/fuel separator filter. Start/run motor, motor not running properly,spoke with customer about the motor, and he agreed to having carbs rebuilt, but if that does not help the motor, A B Seas Marine will go no further on the motor due to age and possible intemal  problems.  Disassemble carbs, soak, clean and reassemble using new  carb repair kits. Start/run motor and having carbs rebuilt did not motor problems. Motor coughing and has a lean pop. running properly.
Submitted: 6 years ago.Category: Boat
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Answered in 15 minutes by:
8/28/2011
Marine Mechanic: Tan, MerCruiser Certified Technician replied 6 years ago
Tan
Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 11,278
Experience: 40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
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Hi my name is***** will assist you.

There is a recirculation system # 57,29 & 46 are the recirculation components that recirculates unburned fuel from the reed boxes and circulates the unburned fuel to the cylinders. These hoses and series of valves get dirty and stick open the hoses crack and deteriorate causing a lean idle pop or sneeze. Check all the small hoses and check valves for proper operation. The valves are one way valves so if you can blow air through the valve both ways replace or clean the check valves and replace the recirculation hoses. Diagram of 1985 J120TLCOS Evinrude / Johnson Johnson Outboard CYLINDER & CRANKCASE Diagram and Parts

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Customer reply replied 6 years ago

Thank you for your reply I will look at the engine and see if I find any issues with that. Thanks What valves specificly are you thinking that could have the issue?

I looked at Valve 13 (check valve assy) I am able to blow air in all directions it that Correct?

This is for a lean pop on a Johnson(###) ###-####outboard motor J120TLCOS Engine series G702732.

Marine Mechanic: Tan, MerCruiser Certified Technician replied 6 years ago

There are check valves on each cylinder check all of them. Follow the small hoses from the side of the cylinders to the back of the reed boxes. The valves are one way if it blows both directions the valve is bad and that will cause lean idle pop.

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Customer reply replied 6 years ago
All of the check valves seem to be bad? is that common that all would be bad? I ordered the new ones and will install to see if it makes an improvement. thanks and will accept when the parts come in and at least makes a difference.If we can fix there will be a tip coming your way also.
Marine Mechanic: Tan, MerCruiser Certified Technician replied 6 years ago

For the age of the engine they are most likely original. Since the introduction of ethanol there have been many fuel problems with fuel components. I would suggest replacing the hose also as the ethanol has caused deterioration of the hose.

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Customer reply replied 6 years ago
I just found with the fuel pump where the oil line connects is broken, I looked up to replace and it looks like I would have to buy the whole assy to replace? I do not have a oil tank connected will no pipe going to the fuel pump assy. Would the open oil fitting create an issue? would it be worth the money to get all parts to install the oil tank to pump? Anything else that would be worth the invesment in replacing?
Marine Mechanic: Tan, MerCruiser Certified Technician replied 6 years ago

If you are mixing the oil no need to repair the oil end of the VRO pump. The pumps are pretty expensive so since you are not using the oil end of the pump just keep using it the way are. There is one thing you should do every 100 hours of use is use a can of Engine Tuner ( this is a product you can purchase at your local BRP dealer) to decarbon the engine. This will keep from coking of the piston and clean the build up of carbon on the rings and pistons.

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Customer reply replied 6 years ago
Your answer was not correct, I just got the parts in and replaced. It seems like it is running stronger but even at higher RPM it will cough now, before it did not. Now at high and low RPM it coughs? Any thoughts?
Marine Mechanic: Tan, MerCruiser Certified Technician replied 6 years ago

Does the engine spit fuel out the front of the carburetors when it coughs? This would be a sign of bad reeds. The check valves were bad you checked them even though it didn't fix the issue. You could have more than one thing wrong causing the same symptoms. The only things left are more expensive to fix if the reeds are broken they will give the same symptoms as will upper and lower crankshaft seals and a restriction in the fuel system. Coughing is usually a minor fuel relater lean condition. Now if you have back fire that could be something else. You also have to realize this is 1985. If there is no fuel spitting out the carbs when it coughs then the next thing is the crankshaft seals.

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Customer reply replied 6 years ago
It is spitting fuel back out the carbs. At high RPM it really spits back out? What do you think is wrong with it?
Marine Mechanic: Tan, MerCruiser Certified Technician replied 6 years ago

Remove the carburetors and intake # 1 inspect the reeds # 12. If the reeds are broken or cracked the engine will blow back through the carburetors. If the reads are damages it will be obvious. The reeds should closed with no more than .010 gap of the reed petals to the box. If you have no bro***** *****s then the crank shaft seals are next to be checked. If the top crank seal is bad there will be oil residue blowing out around the timer base. The power head will have to be remove to inspect the lower crank seal.

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Customer reply replied 6 years ago
What are the numbers you are refering to? Are you referancing a diagram if so can you provide?
Marine Mechanic: Tan, MerCruiser Certified Technician replied 6 years ago
Sorry about that meant to post a diagram.Diagram of 1985 J120TLCOS Evinrude / Johnson Johnson Outboard INTAKE MANIFOLD Diagram and Parts
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Customer reply replied 6 years ago

graphicgraphic

The Reeds look to be alright, I attached pictures for you to get your opinion. If this is not the cause you said to look at the top crank seal. Do you have a diagram for that with a #. Let me know what you think of the reeds?

Marine Mechanic: Tan, MerCruiser Certified Technician replied 6 years ago

Check the reed boxes to be sure they are tight in the intake. They had problems with some model where the boxes came loose. Are any of the reeds open more than .010 it's hard to tell from the pics. The reed box is what the reeds are attached to.

Here is the upper #4 and lower # 13 seals.Diagram of 1985 J140TLCOS Evinrude / Johnson Johnson Outboard CRANKSHAFT & PISTON Diagram and Parts

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Customer reply replied 6 years ago

All the reeds and boxs look good. After getting everything back together it runs better.. It still has a light cough/pop. As I let the rpm go down to idle it just puters out now instead of the cough/pop putting it out, any suggestions? But it seems like we are getting somewhere. thanks again for the help.

Marine Mechanic: Tan, MerCruiser Certified Technician replied 6 years ago

Play with the idle adjustments and idle timing. These engines are very finicky and setting to spec doesn't always work.

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Marine Mechanic: Tan, MerCruiser Certified Technician replied 6 years ago
I see you opened another question. Check your engine temperature should be around 130 to 140*F if the engine is running to cool it will act the way it is in the video. Why didn't you send the video?
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Customer reply replied 6 years ago
I found this when I was pulling the spark plugs, it does not seem correct?
Marine Mechanic: Tan, MerCruiser Certified Technician replied 6 years ago
What did you find?
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Customer reply replied 6 years ago

did the video not post? here is the link:

http://www.youtube.com/watch?v=WAq8Ye85TCs

Marine Mechanic: Tan, MerCruiser Certified Technician replied 6 years ago

You have a bad power pack # 24 or trigger # 9. The trigger can be tested with an ohm meter 35- 45 ohms on white to blue,purple, green, pink . The charge coil will be good if it were bad you would have no spark and it's not likely that 2 coils will be bad and not likely that the trigger is bad on 2 cylinders.Diagram of 1985 J120TLCOS Evinrude / Johnson Johnson Outboard IGNITION SYSTEM Diagram and Parts

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Customer reply replied 6 years ago
Well I just replaced the power pack and that was not it.I pulled the spark plug and it was wet so its getting fuel, I left the spark plug out and started the motor and saw that it was working geving sparks so it must be something internal on the left side there? any suggestions?
Marine Mechanic: Tan, MerCruiser Certified Technician replied 6 years ago

So you have spark now. The pack must have been bad as you have spark now. The fuel is from flooding carburetors. The only way to have allot of fuel in the cylinders is from the carburetor. Squeeze the primer bulb and look down the throat of the carburetors watch for fuel pouring out the high speed nozzle. If fuel is pouring into the carbs remove the carbs check for debris in the inlet needle or float height adjust. Should be parallel with the carb body when inlet needle is seated.

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Customer reply replied 6 years ago
Replacing the power pack did not do anything I can still remove both spark plugs on the left side and nothing happens. I probably was getting spark before replacing. I dont think even if the carb was flooding that the whole one side cylinder not working? Any suggestions?
Marine Mechanic: Tan, MerCruiser Certified Technician replied 6 years ago
If the cylinders are flooded with fuel the engine will not fire the spark plugs. I am going to opt out for another expert to help.
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Customer reply replied 6 years ago
Well I just replaced the power pack and that was not it.I pulled the spark plug and it was wet so its getting fuel, I left the spark plug out and started the motor and saw that it was working geving sparks so it must be something internal on the left side there? any suggestions?
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