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1984 75hp Mercury won't start but runs great after !!

J

joediv

Member
Only will start when I give carbs a shot of starter fluid! Runs great after it's started. Sometimes stalls when put in reverse/forward when cold. I tried the manual choke in case the electric wasn't working( no luck), replaced inline fuel filter, bulb pumps up hard and like I said it runs great after started ( And warmed up a bit). I can't find any videos on how to remove carbs ( 4cyl 2 carbs) 1984 75hp 2 stroke mercury
 
Some will argue----I would look into installing an electric primer such as found on Johnson / Evinrude motors.-----Lots of used ones around for cheap.-----That should end starting problems for you.-----System works like you injecting starting fluid but always there at the push of the key or button.
 
it has an elec choke and a manual one, do u have a link for this " elec primer"? I was thinking that the carbs may be dirty as the motor sat for a year when I bought the boat ( motor did start but I'm guessing the guy had it warmed up before I arrived), I did run a tankful with seafoam in the gas but no luck. I was going to remove them and give them a good cleaning/rebuild. I appreciate your advice and replies, thank you.
 
Well, ---Yes I know they have electric choke on them.-----But due to age / wear and tear / and other issues it no longer works as you have proven with the use of quick start.-----Step # 1 is to learn how one of those electric primers works on Johnson / Evinrudes and perhaps adapt it to your. Mercury outboard.----It is only my opinion but I consider it an easy retrofit.
 
It is not technically a choke, in the sense that it is a butterfly valve in the throttle body of the carburetor. It is a very small valve that injects fuel directly behind the carburetor into engine intake. When you push in the key can you should hear the "choke" solenoid click? Is there a very small cable connecting the "choke" solenoid/manual actuator to the back of the carburetors? If all the parts are there and functioning then you need to clean the carburetors. If functioning properly, it only takes a few seconds of "choking" it inject enough fuel to get the engine to start.
 
racerone said:
Well, ---Yes I know they have electric choke on them.-----But due to age / wear and tear / and other issues it no longer works as you have proven with the use of quick start.-----Step # 1 is to learn how one of those electric primers works on Johnson / Evinrudes and perhaps adapt it to your. Mercury outboard.----It is only my opinion but I consider it an easy retrofit.
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I like this idea but where do I find out the necessary info to install, mainly what pressure pump is needed, I assume i'd hook it to a pos lead that goes on and off with the key but should the pump put out 1-9psi or 2-6 or ????? Thanks
 
The primer bulb on the hose is a manual pump.----It is needed to fill the carburetors for initial start of the motor.----Once the carburetors are full the primer bulb does nothing !!----Once motor is running the fuel pump on the motor keeps carburetors full.--------Best for you to learn some of the basics of how things work, sorry to be blunt here.
 
racerone said:
The primer bulb on the hose is a manual pump.----It is needed to fill the carburetors for initial start of the motor.----Once the carburetors are full the primer bulb does nothing !!----Once motor is running the fuel pump on the motor keeps carburetors full.--------Best for you to learn some of the basics of how things work, sorry to be blunt here.
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Being blunt is not an issue, I was aware of their function but was wondering if I'd keep the bulb to prime the electric fuel pump before trying to start the engine. I assume the answer would be yes so the sequence would be, gas tank-filter-primer bulb-electric fuel pump-another filter maybe then to motor!
 
The Johnson / Evinrude electric primer is NOT a pump.-----It is a valve that opens when 12 volts is applied and the fuel at pressure is sprayed into the intake.
 
racerone said:
The Johnson / Evinrude electric primer is NOT a pump.-----It is a valve that opens when 12 volts is applied and the fuel at pressure is sprayed into the intake.
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Sorry for my ignorance but now I'm confused, when I search for elec fuel primer I also get many fuel " pump" results!! Are we talking about the same thing? I'm thinking by applying some pressure through the gas line that it will result in more gas being pushed through for cold start.
 
The only pressure used in this system is what is in the fuel hose from umping the bulb. And that's normally enough.

Jeff
 
fastjeff said:
The only pressure used in this system is what is in the fuel hose from umping the bulb. And that's normally enough.

Jeff
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hi Jeff, thanks for taking the time to respond to my thread. What would you suggest as a course of action to help with the startup of the motor. I pump and pump and choke and choke to no avail, then when I give it a squirt of starting fluid, bang, she starts right up!!!! I liked the idea of a electric fuel pump as I'd rather not take the carbs off( not sure of my ability to NOT screw that up). It's a pain in the a$$ to remove the carb covers to squirt the start fluid in. I have noticed that the primer bulb doesn't get and stay as hard as I would expect and seems to work better when I squeeze it in the vertical position!!! Once I've got it started and run for a bit it will then start up without any prodding.Should I try to rebuild the fuel pump( if I can find it). I'm also wondering if the carbs could just be dirty!
 
Follow the fuel hoses to find the factory pump on your motor.-----And no a primer bulb does not stay hard once motor is running !!
 
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