1980 Mercury 150 V6 Fuel Issues

[dingbat]

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?

No, that is not normal.
You have a leak somewhere in the fuel system. Motor will not run as intended until the problem is resolved.

 

[That old Mercury]

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

Are you running that motor with carb cover off carb silencer ?
And motor cover off?

 

[ncp546]

Just wanted to do a short update. I checked all the floats again...somehow carb 2/3 had a float that looked a bit lower from when i last checked. Got it back to where it measured out by the book. I dont think its enough to be off to make it run this bad but never know. i checked the trick with the enrichment valve and the primer bulb, looks like no flow when the bulb gets hard through the valve. I have some plans this weekend but still gonna try my hardest to stay ontop of it considering we get only about 3 real months of summer here in wisconsin. If the motor fails and seems no different i will check the timing on it. Again i am incredibly grateful for everyone's time and knowlege you share here with my headache!

 

[That old Mercury]

Just wanted to do a short update. I checked all the floats again...somehow carb 2/3 had a float that looked a bit lower from when i last checked. Got it back to where it measured out by the book. I dont think its enough to be off to make it run this bad but never know. i checked the trick with the enrichment valve and the primer bulb, looks like no flow when the bulb gets hard through the valve. I have some plans this weekend but still gonna try my hardest to stay ontop of it considering we get only about 3 real months of summer here in wisconsin. If the motor fails and seems no different i will check the timing on it. Again i am incredibly grateful for everyone's time and knowlege you share here with my headache!

Wisconsin!
Wow it gets cold thier!
Was up in Greenbay in January one time -25 F all week . snow was like 10' tall and all the side walks were like a maze due to the high snow banks.
Awesome fried cheese curds at Lambeau Field
One carb feeds two cylinders if it is a 3 carb motor , so you could have 2 flooded out cylinders not working . Please update when you try it.

 

[racerone]

I do not believe fuel goes through the primer valve when you operate the bulb on the hose.-----The primer valve ( when open ) allows fuel to flow from the carburetor to go directly into the engine.

 

[That old Mercury]

I do not believe fuel goes through the primer valve when you operate the bulb on the hose.-----The primer valve ( when open ) allows fuel to flow from the carburetor to go directly into the engine.

You are Correct.
My thoughts were if its leaking the carb would be empty, so you would not see gas dripping through the hose unless u filled the carbs back up with primer bulb.
I would try to blow air through it.
I gave several test options.

 

[That old Mercury]

I do not believe fuel goes through the primer valve when you operate the bulb on the hose.-----The primer valve ( when open ) allows fuel to flow from the carburetor to go directly into the engine.

racerone
You are way smarter than i am
And i got a question for you.
Say ncp546 unhooked his hoses at some time from the primer valve and put them back on backwards.
Would engine vacuum at a higher rpm be able to open the valve and suck gas constanly into the motor?

 

[ncp546]

Thanks Gents as always for the recommendations. I was able to get back by the boat, anyone ever mess with the bleed system? I just found two very very small slices in the hoses. Replaced them out, this is the best I’ve ever heard the boat run on the muffs! Not nearly as much fuel being burnt very responsive! Not sure if this was the issue or still moving those float bowls a little better. Is fuel supposed to work its way through those bleed hoses? Regardless tomorrow or Monday I’ll be dropping it back into the lake for a test. I also checked the timing with a gun per manual, seems very close to where it should be! I’ll keep everyone posted.

 

[That old Mercury]

The ones from the cylinder back to the intake ? They keep gas from puddling up in engine. Could affect it a lot! When i bought my boat rats had chewed them off , i replaced them wrong and motor ran rough till i got them right.
Need a good hose to replace them with , the cheap hose i started with would blow a hole in it and gas and oil go every where.
If you use a clear hose you will see excess gas circulating back through it.
Had good luck with the yellow tygon hose. It the hose they use on weedeaters gas lines
Them old mercury carbs can be rough to get dialed in sometimes

 

[ncp546]

The ones from the cylinder back to the intake ? They keep gas from puddling up in engine. Could affect it a lot! When i bought my boat rats had chewed them off , i replaced them wrong and motor ran rough till i got them right.
Need a good hose to replace them with , the cheap hose i started with would blow a hole in it and gas and oil go every where.
If you use a clear hose you will see excess gas circulating back through it.
Had good luck with the yellow tygon hose. It the hose they use on weedeaters gas lines
Them old mercury carbs can be rough to get dialed in sometimes

Im starting to think this was the issue! once again i trusted the mechanic the prervious owner took it too. Nope new fuel lines and bypass hoses...Fuel lines were replaced the bypass might have not been! The small cracks were by the carb corners only thing i can think of is that it was either pinched by me...or previous owner. The cracks were so small that on the black hose i couldnt even see the wetness from the fuel. But they were definitely cracked. Fingers crossed!

 

[That old Mercury]

Im starting to think this was the issue! once again i trusted the mechanic the prervious owner took it too. Nope new fuel lines and bypass hoses...Fuel lines were replaced the bypass might have not been! The small cracks were by the carb corners only thing i can think of is that it was either pinched by me...or previous owner. The cracks were so small that on the black hose i couldnt even see the wetness from the fuel. But they were definitely cracked. Fingers crossed!

Check the ones behind the 2 cdi switch boxes , hard to see them without unbolting them.

 

[Faztbullet]

Say ncp546 unhooked his hoses at some time from the primer valve and put them back on backwards.
Would engine vacuum at a higher rpm be able to open the valve and suck gas constanly into the motor?

Nope

 

[Faztbullet]

Check the restrictors to see if they are stopped up. Use a pair of long tipped needle nose and pull hose off valve while engine is running. Fuel mist should spray out like hair spray from a can. If its looks lumpy or dribbles valve needs cleaning or replaced. There is a bleed line routing diagram in that manual and your motor should only have 5 lines.

 

[ncp546]

Appreciate it fellas, i will try what fazbullet recommends. Meanwhile quick question. I found the diagram online, this was the only bypass tube not hooked up. i believe it goes to the airbox but i could be wrong as the diagram online shows it in the middle between carb1 and 2. But i do not have a port there, just two down low. Attaching Pics here. (I am still getting the error from the admin saying i cant upload pics. So i will upload them elsewhere with a link to them here)

IMG-6868 hosted at ImgBB

Image IMG-6868 hosted in ImgBB

ibb.co

IMG-6871 hosted at ImgBB

Image IMG-6871 hosted in ImgBB

ibb.co

 

[That old Mercury]

Appreciate it fellas, i will try what fazbullet recommends. Meanwhile quick question. I found the diagram online, this was the only bypass tube not hooked up. i believe it goes to the airbox but i could be wrong as the diagram online shows it in the middle between carb1 and 2. But i do not have a port there, just two down low. Attaching Pics here. (I am still getting the error from the admin saying i cant upload pics. So i will upload them elsewhere with a link to them here)

IMG-6868 hosted at ImgBB

Image IMG-6868 hosted in ImgBB

ibb.co

IMG-6871 hosted at ImgBB

Image IMG-6871 hosted in ImgBB

ibb.co

Cant open pictures,
With engine off
since you had carbs off , with your boat in neutral selected make sure all your carb butterflies are completely closed.
With motor still off push shifter to wide open and make butterflies are wide open , but not past wide open. Just a thought
Good luck and keep us updated!