Mercury 60 choking down

[pcobb]

My little Merc 60 (3 cyl 1994) outboard acts like it's running out of gas. It starts fine and takes off great, then starts choking down as if starved for gas. You can shut down to a idle and let it idle for a minute and then hit it again and it takes off normally, then starts choking down again. I've changed the filter and it didn't help. This morning I took the gas tank off and cleaned it out. Not very dirty. I put the gas back into the tank by filtering it thru a piece of felt material. Checked the pump bulb the best I know how (disconnected and blew thru, pumps up and holds, squirts when pumped and push in on release valve at engine end) and it looks ok to me. What else can/do I need to check???? Thanks for your help.

 

[mercerfisherman]

Re: Mercury 60 choking down

Check your fuel pump. Maybe it's time to replace it.

 

[Kevin W]

Re: Mercury 60 choking down

it could be the fuel pump, it could also be leaking, stuck or clogged float valves.
sometimes the fuel pressuure is low enough to not leak at idle but higher rpms it may overflow the carb and choke the engine with too much fuel.
possible junk in the carb.
Try squeezing the primer bulb when it is at idle.
not real hard but firm.
it should not change the idle.
if it does you most likely have overflow.
check for dripping carburators after it dies at higher rpm too.
this is also a symptom of float issues.
when it stalls does it spit and sneeze before failure?
if so you are correct with a lean condition.

 

[pcobb]

Re: Mercury 60 choking down

Check your fuel pump. Maybe it's time to replace it.

Is this a piece that someone can replace easily? I'm pretty handy with tools, but don'e even know what it looks like.

 

[pcobb]

Re: Mercury 60 choking down

it could be the fuel pump, it could also be leaking, stuck or clogged float valves.
sometimes the fuel pressuure is low enough to not leak at idle but higher rpms it may overflow the carb and choke the engine with too much fuel.
possible junk in the carb.
Try squeezing the primer bulb when it is at idle.
not real hard but firm.
it should not change the idle.
if it does you most likely have overflow.
check for dripping carburators after it dies at higher rpm too.
this is also a symptom of float issues.
when it stalls does it spit and sneeze before failure?
if so you are correct with a lean condition.

Kevin thanks for the reply. I haven't checked for the leaks you mentioned, I just found the post. But, the motor doesn't die, it just cuts back to a little more than idle. Some times it will pick up again momentarily then go back to a fast idle again. Like it's getting enough gas to run, but not to get any pickup and go quantities of fuel. I did try to squeeze the bulb while it was sitting in the slip running and saw or hear no change in the motor speed. Is there a web site that might show me what the fuel pump looks like?

 

[Kevin W]

Re: Mercury 60 choking down

mercury parts express has parts breakdown diagrams online.
a fuel pump is a pretty easy fix.
i would also suggest getting a service manual.
they are a wealth of info and have all the diagrams you would need.

 

[pcobb]

Re: Mercury 60 choking down

mercury parts express has parts breakdown diagrams online.
a fuel pump is a pretty easy fix.
i would also suggest getting a service manual.
they are a wealth of info and have all the diagrams you would need.

Thanks, I looked at mercury parts express and found three pumps so I've got to go look at my motor more closely and I'll also look at the other thinks you mentioned and see if I can figure this thing out. I'll let you know how it turns out.

 

[Rockonafly]

Re: Mercury 60 choking down

My 96 60 hp had a similar problem. The problem was the outlet check valve for the squeeze bulb came loose and was blocking the flow intermittently. The only way I found it was squeezing the bulb and I felt something hard in it.

Rockonafly