Mecury Inline 1400 6cyl no start

[Hawk78]

I have a mid 70's Merc 1400 140hp inline 6. It is a real pain in the butt to start cold. Carbs are clean and functioning, has plenty of spark and the choke seems to work good. Excellent compression in all cylinders, timing is set to spec. But for some reason the only way I can get this to start is if i use a spray bottle and squirt gas into the carbs while cranking the motor. Its almost as if the motor is not developing enough vacuum over the carb ventures to get the fuel into the motor. I have plenty of fuel pressure and gas leaks out the front of the carbs after intense cranking. Once i get the motor running and it gets hot it runs fine and starts on the first crank. Its just that first cold start i have to flood the case with a ridiculous amount of fuel to get it to fire???? Any Ideas?? Some one told me there are crank seals that go bad causing cold start issues???

 

[Lone Duck]

Re: Mecury Inline 1400 6cyl no start

If your crank seals are bad you would have a lean running condition, which would cause over rev and a break down of pistons and cyl. ( poor compression ) Give it full choke, fast idle, do this two or three times. Then walk back and pump the bulb again, pump it hard then give it 1 more slow steady pressure. Are you sure your choke is full closed ? Also try opening idle mixture screw 1/4 turn . After all else.

 

[Hawk78]

Re: Mecury Inline 1400 6cyl no start

This motor has an electric fuel pump that maintains constant fuel pressure. I have messed with the idle screws and it idles fine once it starts. I have to give it full idle throttle squirt a lot of gas in each carb close the choke and crank after about 15 minutes it will finally fire. Its almost like it is very lean even though the carbs are flooding it and my squirt bottle is flooding it. I have also pulled all the spark plugs and filled all the cylinders with 10 squirts of gas. That seemed to make it fire right up. Are you sure this isnt a crank seal problem?

 

[Lone Duck]

Re: Mecury Inline 1400 6cyl no start

If it was crank seals you would see evidence of Raw fuel around bottom of engine and leg . Hold a piece of card board over the carb throats and crank it over. If it fires your choke is not working properly. What is your compression ? Around 125 to 140 across the board ? Leaking seals would not allow it to run fine after starting. What is the R P M at WOT ? When it is running, is it still spitting fuel out of the carbs ? Are you getting RAW fuel out of the exhaust while running ?

 

[CharlieB]

Re: Mecury Inline 1400 6cyl no start

Do you have power tilt/trim?

Level the motor before starting, much trim up and they get more difficult to start.

When was the last time your starter was rebuilt/cleaned/lubed?

Clean the battery cables, BOTH ends. Low/slow cranking speed contributes to hard starting.

 

[Bondo]

Re: Mecury Inline 1400 6cyl no start

Ayuh,... Not that I've really got an Answer, but merely a personal observation...

About Every in-line Merc. I ever had,...
I had to Choke the living schit out of it, 1st start of the day,...
After that, they always ran,+ started like a Champ...

 

[Lone Duck]

Re: Mecury Inline 1400 6cyl no start

Ayuh,... Not that I've really got an Answer, but merely a personal observation...

About Every in-line Merc. I ever had,...
I had to Choke the living schit out of it, 1st start of the day,...
After that, they always ran,+ started like a Champ...

Yes! I am beginning to think that the electric fuel pump is not supplying enough pressure for initial start up. IF his choke is working properly. Did that engine come with elec fuel pump or is it an add on ?

 

[Chris1956]

Re: Mecury Inline 1400 6cyl no start

Electric fuel pump is an add on. It may or may not be an issue. Those motors are hard to start when cold, but 15 minutes is outrageous. I would remove the elec fuel pump as it could be a real fire hazard if the fuel line ruptures. The original mechanical fuel pump worked OK.

Is it possible the original fuel pump has a bad leak flooding the crankcase?

 

[Lone Duck]

Re: Mecury Inline 1400 6cyl no start

Electric fuel pump is an add on. It may or may not be an issue. Those motors are hard to start when cold, but 15 minutes is outrageous. I would remove the elec fuel pump as it could be a real fire hazard if the fuel line ruptures. The original mechanical fuel pump worked OK.

Is it possible the original fuel pump has a bad leak flooding the crankcase?

I am not being a smart ***. But read up on the 2 cycl theory . He claims it is starving for fuel. If there was fuel in crank case it should fire.

 

[Hawk78]

Re: Mecury Inline 1400 6cyl no start

If it was crank seals you would see evidence of Raw fuel around bottom of engine and leg . Hold a piece of card board over the carb throats and crank it over. If it fires your choke is not working properly. What is your compression ? Around 125 to 140 across the board ? Leaking seals would not allow it to run fine after starting. What is the R P M at WOT ? When it is running, is it still spitting fuel out of the carbs ? Are you getting RAW fuel out of the exhaust while running ?

Thanks for all the advice guys. When I shut off the motor at least a half cup of fuel drains out the exhaust or some crack down near the bottom of the motor. I have electric choke butterflies that cover all three carbs when i push the choke button so i know my choke is working. My cylinder compression ranges from 95 to 120 psi across all six cylinders. WOT rpm is 5200. I can't tell if fuel is coming out the exhaust when running but i do see fuel when i shut it off. Is does not spit fuel out the carbs while running only after cranking the motor for 15 minutes with the choke does fuel begin to run out of the carbs so i know its getting some fuel. The Electric pump was installed because the mech pump was not able to get fuel from the tank in the front of the boat. I installed the pump with a fuel pressure regulator so as not to overwhelm the carbs I have messed with thme but plenty of fuel is getting to the carbs they just need more. When I removed the block offs for the mech pump and turned on the pump it flooded the case and the motor started. I have spark maybe its not a big enough? This motor takes a lot of fuel to start and then revs high because of all the fuel then returns to idle and runs ok a little rough but it runs.

 

[CharlieB]

Re: Mecury Inline 1400 6cyl no start

Tell us more about this "fuel pump block off plate".

Is the old fuel pump still in the fuel line?

Have you "messed" with the idle mixture screws?

Sounds like you need to be getting into your carbs, adjust float levels EXACTLY by-the-book, adjust the idle mixture screws (again -- by-the-book).

Inline 6's generally idle very well once the carbs are sorted out and idle mixture is perfected.

They DO like a LOT of choke to get started from stone cold, but once warmed all roughness should be gone.

 

[Hawk78]

Re: Mecury Inline 1400 6cyl no start

This motor was equiped with two little rubber diaphrams that fluttered back and forth with crank case vacuum. That fluttering was supposed to pump fuel. However i have this motor on a old halet flat bottom and the fuel tank is in the front. The little pumps on this motor would not pump fuel to the motor from that distance so the electric pump was installed with two block off plates where the old rubber diaphrams were. The motor was not getting fuel at all when I bought it this way. With the electric pump the motor runs good when it starts.

 

[Moody Blue]

Re: Mecury Inline 1400 6cyl no start

Thanks for all the advice guys. When I shut off the motor at least a half cup of fuel drains out the exhaust or some crack down near the bottom of the motor. I can't tell if fuel is coming out the exhaust when running but i do see fuel when i shut it off. Is does not spit fuel out the carbs while running only after cranking the motor for 15 minutes with the choke does fuel begin to run out of the carbs so i know its getting some fuel. I installed the pump with a fuel pressure regulator so as not to overwhelm the carbs I have messed with thme but plenty of fuel is getting to the carbs they just need more. When I removed the block offs for the mech pump and turned on the pump it flooded the case and the motor started. I have spark maybe its not a big enough? This motor takes a lot of fuel to start and then revs high because of all the fuel then returns to idle and runs ok a little rough but it runs.

Something is not adding up. You have plenty of fuel available to the carbs based on your statements above. Trying to force more fuel into this thing is not going to resolve the problem. Something else is amiss.

What pressure is the regulator providing to the carbs? What type of pump is used and is there a return line from the carbs or regulator to the tank? Sounds like you are getting too much fuel that is not being consumed properly.

 

[Hawk78]

Re: Mecury Inline 1400 6cyl no start

I think I have narrowed this down to a float level problem unfortunaty I cannot find a way to adjust the float level. Anyone ever done this procedure before? There is a small spring on top of each float. The problem seems to be that the

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floats are to low in the bowl I can't seem to find a way to make them float higher in the bowl?

 

[Droll]

Re: Mecury Inline 1400 6cyl no start

I think I have narrowed this down to a float level problem unfortunaty I cannot find a way to adjust the float level. Anyone ever done this procedure before?

There is a small spring on top of each float.

Should be 3/32" from the top of the spring and down to the float top

The problem seems to be that the floats are to low in the bowl I can't seem to find a way to make them float higher in the bowl?

If they floats to low the only cure are to replace them ..are still available from Mercury..

Mercury #1395-8673 Float assy, are $10.76 pr float.



Arne Kjetil

 

[Chris1956]

Re: Mecury Inline 1400 6cyl no start

Hawk, Those motors have two choke plates, top and mid carb. Anything else is a "custom" item, as was the electric fuel pump. If the carb floats are set correct, and the floats themselves are good, you will have good results. Inspect the floats carefully. The original ones were foam that tended to disolve. The newer floats were hard white plastic, which tended to crack. Replace all that are bad, as well as the inlet needles and seats. The original ones were brass with rubber insets, nylon or ss needles. Newer are all brass seats and ss needles with neopreme tips.

 

[Hawk78]

Re: Mecury Inline 1400 6cyl no start

Thanks for the diagram I hopefully this will help.