1980 Mercury 150 V6 Fuel Issues

[ncp546]

Hello all. I am finally turning to the forums after throwing in the towel on this project. I have a 1980 Mercury 150 V6. In short here is what is happening...

Motor will start and run/idle. There is 0 power out on the water. Full throttle gets me about 4mph and i smoke the entire lake out. Initially i thought the stator was bad and one half of the motor was not firing. I have noticed there is excessive fuel coming from the carb throats and milky as water may be coming into the fuel. No tell tale as well. Black sut looks to be coming out of exhaust and as well as fuel coming out the exhaust into the water creating the "rainbow" effect in the water.

BACK TO THE SHOP.

I noticed previous owner had the stator changed. Verified spark on all cylinders.. good on all 6. Rectifier looks clean not burnt up. I then turned to the enrichment valve on the side. New Lines and the motor seems to run well when the manual spinner on top is turned clockwise. Going clockwise will kill the motor completely. Verified it is working when it clicks when the key is pushed and fuel is flowing through the lines. Changed all plugs, i noticed the old ones are black and oily assuming too rich but didnt notice water on them which i thought potentially one of the head gaskets could have been leaking since fuel looked to be milky from carbs. Cleaned tank, new fuel, blew lines out, rebuilt all 3 carbs and checked float heights per the SOLEC manual. Compression tested 150 pounds on all 6. Changed thermostats and check the Poppett valve for obstructions was clear. Checked the lines from thermostats they get water but still none to the bottom hose where the tell tale comes out of motor. Replaced water pump housing, gaskets and impeller. Retested, same results. Fuel still looks milky, and i am getting very little response from throttle and tons of smoke. My carbs are non adjustable with needles from the outside. Only other thing i can think of is to re time the motor and that maybe the motor could be stuck in a "limp" mode as there is no overheat speaker on this boat. I am reaching out to see if there is any other things i could have missed as i am very new to these older outboards. I sincerely appreciate everyones input and time they are willing to spend to help me sort out what could be an issue. Thank you in advance!

 

[Dukedog]

first thing ta do is junk tha seloc... its worthless.. look on ebay for an oem manual for your motor..................

 

[racerone]

Mark flywheel with TDC for each cylinder.----Then check where each is firing using a timing light.

 

[ncp546]

Mark flywheel with TDC for each cylinder.----Then check where each is firing using a timing light.

Thank you that’s a good start. I was reading yesterday through some old forums that the milky I see from the throats can be normal from the humidity hitting the cold bowls which it has been crazy humid here the past few weeks with rain. The tell tale I’m also reading opens around 140F? So I’m not even sure if my motor is getting that hot yet due to it running so poorly. I would splash a bit of water onto the cylinder heads every few minutes to see if I could see steam or sizzle and nothing. I think I’ll try seeing if the timing is still on, if off I’ll adjust. Appreciate the reply

 

[Dukedog]

if carbs and fuel pressure are right you should not see any accumulation of any fuel mixture in tha throats other than a slight residue no mater what tha humidity. might check tha reeds....

it has 143* stats so that should be good.. if you don't have an over heat warning buzzer ya need to fix and/or replace.. also a water pressure gauge would be a big benefit also.......

 

[cyclops222]

MILKY gasoline ?? You will never run right. Find how the water is getting into the gasoline !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Then correct the cause. Do not waste time and money until clean gasoline is in all of the fuel system. So many ways water can get into the gasoline before you buy it.

 

[Faztbullet]

Sent you link....

 

[That old Mercury]

Hello all. I am finally turning to the forums after throwing in the towel on this project. I have a 1980 Mercury 150 V6. In short here is what is happening...

Motor will start and run/idle. There is 0 power out on the water. Full throttle gets me about 4mph and i smoke the entire lake out. Initially i thought the stator was bad and one half of the motor was not firing. I have noticed there is excessive fuel coming from the carb throats and milky as water may be coming into the fuel. No tell tale as well. Black sut looks to be coming out of exhaust and as well as fuel coming out the exhaust into the water creating the "rainbow" effect in the water.

BACK TO THE SHOP.

I noticed previous owner had the stator changed. Verified spark on all cylinders.. good on all 6. Rectifier looks clean not burnt up. I then turned to the enrichment valve on the side. New Lines and the motor seems to run well when the manual spinner on top is turned clockwise. Going clockwise will kill the motor completely. Verified it is working when it clicks when the key is pushed and fuel is flowing through the lines. Changed all plugs, i noticed the old ones are black and oily assuming too rich but didnt notice water on them which i thought potentially one of the head gaskets could have been leaking since fuel looked to be milky from carbs. Cleaned tank, new fuel, blew lines out, rebuilt all 3 carbs and checked float heights per the SOLEC manual. Compression tested 150 pounds on all 6. Changed thermostats and check the Poppett valve for obstructions was clear. Checked the lines from thermostats they get water but still none to the bottom hose where the tell tale comes out of motor. Replaced water pump housing, gaskets and impeller. Retested, same results. Fuel still looks milky, and i am getting very little response from throttle and tons of smoke. My carbs are non adjustable with needles from the outside. Only other thing i can think of is to re time the motor and that maybe the motor could be stuck in a "limp" mode as there is no overheat speaker on this boat. I am reaching out to see if there is any other things i could have missed as i am very new to these older outboards. I sincerely appreciate everyones input and time they are willing to spend to help me sort out what could be an issue. Thank you in advance!

Hi
Can you post a picture of the carbs with the milky condensation?
On muffs with water turned on.
Run using your fast idle lever to roughly 2,500 rpm for about 10 minutes, let it cool then check your spark plugs again, mark which cylinders the plugs are still real wet.
This may tell you which carb is flooding out.
I am suspecting you still have carbs flooding the engine.
Could be a hole in fuel pump diaphram.
Could be timming.
Does it cough or sneeze when idling?
My 1983 150 v6 black max pees out tell tale as soon as it starts.
I replaced everything electronic and everything dealing with the cooling,
Mine was still the carbs after rebuilding them , manual was wrong on float heights

 

[That old Mercury]

Hi
Can you post a picture of the carbs with the milky condensation?
On muffs with water turned on.
Run using your fast idle lever to roughly 2,500 rpm for about 10 minutes, let it cool then check your spark plugs again, mark which cylinders the plugs are still real wet.
This may tell you which carb is flooding out.
I am suspecting you still have carbs flooding the engine.
Could be a hole in fuel pump diaphram.
Could be timming.
Does it cough or sneeze when idling?
My 1983 150 v6 black max pees out tell tale as soon as it starts.
I replaced everything electronic and everything dealing with the cooling,
Mine was still the carbs after rebuilding them , manual was wrong on float heights

One other thing to check.
If it has the electric fuel primer that clicks when you push in the key.
Remove the hose that goes to the carb with engine off and squeez your fuel line bulb and see if gas squirts out the hose.
No gas should come out unless you switch on the key and push it in.
Those have been known to leak gas into the engine and keep it flooded out.
Maybe with everyones ideas you can go Fast again !

 

[ncp546]

Wow, lots of interesting things to try here. Just want to say thank you to everyone willing to sit here and spend their time trying to help me with this. I will be back at the boat here in the next day or so. I will run a few of these and grab some pictures of the milky I see. I will also try the 2500rpm run time as well as the solenoid check with the line pulled. No sneeze or cough when at idle but I have noticed after it idling for a while it will get more fuel consumption and more smoke, rev up and give it a few clear outs and it gets better. Bring it back to idle and it will start to get worse again. I’m thinking I will check the float heights again via not using the SELOC manual but the OE one now that it is in my sight..You are all incredible! Can’t thank you all enough.

 

[racerone]

The hose from the carburetor FEEDS FUEL to the enricher.-----The enricher is NOT a pump that fills the carburetor !

 

[cyclops222]

Thank you Racerone. Have to check out the operation your way.
The marina I used for the new gasoline. It smells very WEAK .
Have to go to my old fuel dock for a sample to compare the 2 places.
Hope I did not buy 10 gallons of old stale gasoline. Marina has very few customers this summer. Actually almost no private boats cruising around. All gas places increased their fuel tank sizes during the peak years. I just can not find all the good old parts & stuff for boats. Gas companies are constantly making worse gas to buy bigger yachts and personal jumbo jets.
Oh well.

 

[That old Mercury]

Wow, lots of interesting things to try here. Just want to say thank you to everyone willing to sit here and spend their time trying to help me with this. I will be back at the boat here in the next day or so. I will run a few of these and grab some pictures of the milky I see. I will also try the 2500rpm run time as well as the solenoid check with the line pulled. No sneeze or cough when at idle but I have noticed after it idling for a while it will get more fuel consumption and more smoke, rev up and give it a few clear outs and it gets better. Bring it back to idle and it will start to get worse again. I’m thinking I will check the float heights again via not using the SELOC manual but the OE one now that it is in my sight..You are all incredible! Can’t thank you all enough.

Still sounds like its flooding by when you rev it up it clears the sparkplugs and the cylinders start back firing.
Did you use oem carb rebuild kits ?
Or those that say they are compatible?
What is your oil mixture ratio?
Thanks Racerone, Enricher valve , that the name i could not remember. And yes it comes from carb bowls then goes to the intake. I think its the bottom hose on the valve , my boat is a ways off so i cant send you a pic If its leaking carb bowl will be empty and you will have to refill them by pumping the gas tank bulb to see if it leaks.
You can take both lines off and see if you can blow through it , if you like the tast of gas !
Compressed air would work but needs to be regulated to roughly 1 to 3 psi. Best i can remember they are low pressure valves .
Someone smarted can confirm this.

 

[That old Mercury]

Wow, lots of interesting things to try here. Just want to say thank you to everyone willing to sit here and spend their time trying to help me with this. I will be back at the boat here in the next day or so. I will run a few of these and grab some pictures of the milky I see. I will also try the 2500rpm run time as well as the solenoid check with the line pulled. No sneeze or cough when at idle but I have noticed after it idling for a while it will get more fuel consumption and more smoke, rev up and give it a few clear outs and it gets better. Bring it back to idle and it will start to get worse again. I’m thinking I will check the float heights again via not using the SELOC manual but the OE one now that it is in my sight..You are all incredible! Can’t thank you all enough.

Before you idle it up high make sure you are getting water out of the tell tale hose first, you dont want your motor overheating if something is not working.

 

[Faztbullet]

Recirculation valves could be stopped up, will cause it to load up at idle

 

[ncp546]

Recirculation valves could be stopped up, will cause it to load up at idle

Anyway I can check this?

 

[ncp546]

I was able to sneak off at lunch and pull the carbs. I got some pictures of the milky I see, since I haven’t ran the boat in a few days most seems to be gone. There is usually more than this however when the boat is running. Unfortunately I’m not sure if floats will be my issue. The OE Manual calls for 1/16” for height, so does the SOLEC manual which I went off of. Since I pulled the carbs I will check regardless again. I also wanted to point out that while the motor was running (I have clear lines for the fuel lines) I could see tons of bubbles being moved around from the enricher valve to the carbs. Normal? Regardless I will get to more testing asap here. You are all incredible and I appreciate all your wisdom you are willing to share with me.

 

[ncp546]

I’m trying to upload photos but am getting this error when so

“The upload failed because the file could not be written to the server. The site administrator will need to resolve this before any files can be uploaded.”

I will try from my computer tonight

 

[That old Mercury]

I was able to sneak off at lunch and pull the carbs. I got some pictures of the milky I see, since I haven’t ran the boat in a few days most seems to be gone. There is usually more than this however when the boat is running. Unfortunately I’m not sure if floats will be my issue. The OE Manual calls for 1/16” for height, so does the SOLEC manual which I went off of. Since I pulled the carbs I will check regardless again. I also wanted to point out that while the motor was running (I have clear lines for the fuel lines) I could see tons of bubbles being moved around from the enricher valve to the carbs. Normal? Regardless I will get to more testing asap here. You are all incredible and I appreciate all your wisdom you are willing to share with me.

On the clear line from enricher to motor i have seen that also, with motor running.
Mine looks like the fuel moves through the hose then reverses and does it constantly. Thats no big deal as long as its not constantly flowing.
If you have the carbs off turn one at a time upside down so the fuel bowl is facing straight up and try to blow through the fuel inlet on the carb , you may need to add a piece of fuel line and put a clamp on it .
Then using your mouth see if you can blow air in , you may need to hold a little pressure for a few seconds. If air flows through hose even a little it could be float needle valve leaking, or where float needle valve brass fitting screws into the carb.
With carb bowl off and carb turned upside down with float facing you the float should be sitting level, and not twisted , on the drop i have mine set at 1/2" .
If your floats are old they may be fuel logged , place each one in a bowl of water and see if they float any.

 

[That old Mercury]

I was able to sneak off at lunch and pull the carbs. I got some pictures of the milky I see, since I haven’t ran the boat in a few days most seems to be gone. There is usually more than this however when the boat is running. Unfortunately I’m not sure if floats will be my issue. The OE Manual calls for 1/16” for height, so does the SOLEC manual which I went off of. Since I pulled the carbs I will check regardless again. I also wanted to point out that while the motor was running (I have clear lines for the fuel lines) I could see tons of bubbles being moved around from the enricher valve to the carbs. Normal? Regardless I will get to more testing asap here. You are all incredible and I appreciate all your wisdom you are willing to share with me.

If you have a lot of fuel everywhere in the front of the carbs it could be moisture just getting trapped buy the 2 cycle oil.
I am only trying to see if you are constantly flooding out.
Thier has been so Great advice from others that you can check as well