PRIMER bulb "PRIMING"

brnschoneck

Petty Officer 1st Class
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Feb 22, 2013
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hi all !!on my 65 merc 650 kf When priming my motor to start wen cold after sitting so u just pump all the air out ?? I been doing a couple xtras not sure exactly dont wanna cause flooding pronblems just wanna make sure i amd oing it right thansk once again for all ur responses ...
 

Part-time

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Re: PRIMER bulb "PRIMING"

On mine I usualy just pump one or twice to get the bulb hard and it's good to go.
 

brnschoneck

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Re: PRIMER bulb "PRIMING"

kkkk sweet thanks jsut makn sure !!!
 

Home Cookin'

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Re: PRIMER bulb "PRIMING"

A guy who knows them said you can't flood the old mercuries!
 

ssobol

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Re: PRIMER bulb "PRIMING"

hi all !!on my 65 merc 650 kf When priming my motor to start wen cold after sitting so u just pump all the air out ?? I been doing a couple xtras not sure exactly dont wanna cause flooding pronblems just wanna make sure i amd oing it right thansk once again for all ur responses ...

On my Yamaha outboard pumping the bulb 'til its hard will flood the engine. What I do is move the throttle from idle to full and back to idle, then start. On a carbed engine, moving the throttle like that will cause the acceleration pump to squirt a bit of fuel right into the carb throat. I found that this works very well although sometimes I may have to try it twice before the engine starts.

I usually store the boat will the fuel tank removed (sometimes for quite awhile) and even then this method reliably starts the boat after a couple of tries.
 

HenryB

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Dec 8, 2012
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Re: PRIMER bulb "PRIMING"

If the bulb is laying flat when it?s at rest it will never really harden, but if the bulb/ check valve is upright when at rest then just a few pumps will get it hard. The check valve isn?t much use if the bulb lays flat at rest. The fuel will back flow and will require a lot of pumping to get it anywhere near firm.

I once watched a guy trying to start his new motor and it was just spinning and doing nothing. I asked if he was using the primer and he looked puzzled. I said to push in on the key when starting. He pushed in on the key and the motor started right up.
 

MH Hawker

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Re: PRIMER bulb "PRIMING"

You should all ways point the arrow up when priming the bulb.
 

brnschoneck

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Feb 22, 2013
Messages
337
Re: PRIMER bulb "PRIMING"

If the bulb is laying flat when it’s at rest it will never really harden, but if the bulb/ check valve is upright when at rest then just a few pumps will get it hard. The check valve isn’t much use if the bulb lays flat at rest. The fuel will back flow and will require a lot of pumping to get it anywhere near firm.

I once watched a guy trying to start his new motor and it was just spinning and doing nothing. I asked if he was using the primer and he looked puzzled. I said to push in on the key when starting. He pushed in on the key and the motor started right up.

excellant to know i sure wasnt pinting it up and i lay it flat wen storing man i luv this sight ive learned so much i woulda never new thanks a lot again happy happy !!!!idk that i push my key in all the x ?? maybe thats y it takes a few times after warmed she fires right up though everytime !!!
 
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brnschoneck

Petty Officer 1st Class
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Feb 22, 2013
Messages
337
Re: PRIMER bulb "PRIMING"

On my Yamaha outboard pumping the bulb 'til its hard will flood the engine. What I do is move the throttle from idle to full and back to idle, then start. On a carbed engine, moving the throttle like that will cause the acceleration pump to squirt a bit of fuel right into the carb throat. I found that this works very well although sometimes I may have to try it twice before the engine starts.

I usually store the boat will the fuel tank removed (sometimes for quite awhile) and even then this method reliably starts the boat after a couple of tries.

y i do take tank out and store in a controlled climate aka my shop !! however i lay bulb dwn in bilge pump to store it ..Ill lean it up from now on thanks guys
 

Silvertip

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Sep 22, 2003
Messages
28,758
Re: PRIMER bulb "PRIMING"

On my Yamaha outboard pumping the bulb 'til its hard will flood the engine. What I do is move the throttle from idle to full and back to idle, then start. On a carbed engine, moving the throttle like that will cause the acceleration pump to squirt a bit of fuel right into the carb throat. I found that this works very well although sometimes I may have to try it twice before the engine starts.

I usually store the boat will the fuel tank removed (sometimes for quite awhile) and even then this method reliably starts the boat after a couple of tries.

Are you aware that most outboards do not have accelerator pumps? And if firming up the primer bulb on your engine causes it to flood, the carbs need new needles and seats.
 

Home Cookin'

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Re: PRIMER bulb "PRIMING"

I've had some motors that the bulb gets rock hard and others that stay soft while you hear fuel passing through; it seems the larger the engine, or th elonger the run, the softer it remains.

Pointing the bulb up is a new trick to me and works like a charm on my 150, which has a long run from the tank, through the seperator and into the motor. Good to learn a new trick after 50 years. But I have a 70 with the bulb in the transom well that doesn't ahve enough slack to point up and it does fine horizontal, and gets hard. On the basic 6 gallon portable, they work fine flat, even one that goes through a seperator.
 

UncleWillie

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Re: PRIMER bulb "PRIMING"

What it supposed to happen.....

Pumping the primer bulb pumps fuel from the tank, through the fuel pump and into the carburetor bowl.
Once the Carb bowl is full, the float shuts the float valve and no more fuel comes in.
The bulb should get hard because there is nowhere to pump the fuel.
If it keeps pumping and floods the engine, the float(s) is/are stuck or a float valve is bad.
Once the engine starts, the float and float valve need to be working or the fuel pump is going to make the engine run very rich, if at all.
The primer bulb is just a manual fuel pump for use before the engine starts.

Pushing in the key, if you have this feature, operated the CHOKE.
It is not a remote primer.
Pushing it in and out 5 times does nothing but operate the choke 5 times.
Push it in and hold it while turning the key.
 

Part-time

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Messages
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Re: PRIMER bulb "PRIMING"

A primer bulb has 2 check valves, 1 at each end.
when you squeez the one closest to the tank closes and pushes fuel up.
When you release the bulb, the valve exiting the bulb closes and draws fuel from the tank.
Holding the bulb pointing up ward could help these valves close back up, but it shouldn't have to.
Either your bulb is getting old.... or quit buying stuff made in china!

Big engines=big carbs so yes, it will take a lot of fuel to fill the larger bowls on each carb untill they are full.
on most carbs the gas will come out of an overflow if a float/needle valve get stuck open and not flood the engine.
Look for gas leaking somewhere under the cowling if the bulb is good and still never goes hard.

The other thing that will keep a bulb from pumping up hard is a leak between the bulb and the fuel tank.
It will not leak gas out, it will draw air into the system and will be extremely difficult to prime and most probably cause the engine to starve for fuel when you try to give it more throttle.
This usualy happens with worn fittings on portable fuel tanks.
 

81_chapparel194

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Aug 7, 2012
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Re: PRIMER bulb "PRIMING"

What it supposed to happen.....



Pushing in the key, if you have this feature, operated the CHOKE.
It is not a remote primer.
Pushing it in and out 5 times does nothing but operate the choke 5 times.
Push it in and hold it while turning the key.

ah hum well my carbs have NO choke butterflies in the carb throats.. when i push my key in it does have an electric primer/mister that sprays gas into the carbs. and its an 81 evinrude 90hp. so when i push my key in i do prime my engine HOWEVER i have to use the primer bulb to get gas to the carbs bowls.
 

UncleWillie

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Re: PRIMER bulb "PRIMING"

ah hum well my carbs have NO choke butterflies in the carb throats.. when i push my key in it does have an electric primer/mister that sprays gas into the carbs. and its an 81 evinrude 90hp. so when i push my key in i do prime my engine HOWEVER i have to use the primer bulb to get gas to the carbs bowls.

Interesting!
Without any choke, do you have to keep giving it a another prime if it starts to lean out on cold days before it warms up?
 

spoilsofwar

Lieutenant Junior Grade
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Jun 29, 2011
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Re: PRIMER bulb "PRIMING"

A guy who knows them said you can't flood the old mercuries!

100% true... I had a '70 Merc 800, I would squeeze till I heard fuel squirting in the carbs, and then squeeze a few more times. It couldn't be flooded.
 

MH Hawker

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Re: PRIMER bulb "PRIMING"

Interesting!
Without any choke, do you have to keep giving it a another prime if it starts to lean out on cold days before it warms up?

Mine also has the electric prime function on a mariner, I just recently had to dig into how it worked a bit deeper, mine has a small hole in the side of the carb and while the motor is being cranked when you push it in to prime a rubber tip covers the hole and causes it to get more gas. On a cold start If I push in the switch it will pick up the rpm`s while its running I may have to push it in a time or two till it idles on its own. It also has a manual prime button on the side of the carb for the pull out choke, but it dose not have a butterfly.

Recently while dropping the LU I found the solenoid plunger laying in the bottom of the cowling. Mercury terms it as a choke solenoid and when installing the new one their was no linkage or any other parts so out of curiosity I dug into it a bit deeper and that was the explanation in the manual.
 

Part-time

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Messages
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Re: PRIMER bulb "PRIMING"

A choke does not necesarily have to be a "buterfly", it just needs to cut off an air suply to enrich the fuel/air mixture.
So the merc/mariner's ruber tip that covers the hole does just that, and is a choke.
The other way to enrich a mixture is to add fuel, like evinrude/johnson do with the primer that give a little squirt of gas directly into the motor.
 
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