3.0 mercruiser starts but won't run

[suwu7]

Hi guys, Im trying to get my boat ready for the water and I'm having some issues. Motor cranked and ran fine just a couple months ago. I tried to crank it the other day to no avail. Motor starts and then runs for a few seconds then kills. If i try to give it gas after cranking it immediately kills. I can't hear the fuel pump kick on when i turn the key but i can't ever remember hearing it kick on. From the research I've done I'm thinking its either the IAC valve or a bad fuel pump. Just looking for someone that may have any advice or has had the same problem. Thanks.

 

[alldodge]

Hi guys, Im trying to get my boat ready for the water and I'm having some issues. Motor cranked and ran fine just a couple months ago. I tried to crank it the other day to no avail. Motor starts and then runs for a few seconds then kills. If i try to give it gas after cranking it immediately kills. I can't hear the fuel pump kick on when i turn the key but i can't ever remember hearing it kick on. From the research I've done I'm thinking its either the IAC valve or a bad fuel pump. Just looking for someone that may have any advice or has had the same problem. Thanks.

:welcome: to iboats

We could use some more info in order to help. You say its a 3.0 but what year, better yet what is the engine serial number? Have no idea if it is carb or EFI

 

[suwu7]

It has a carb, the motor is relatively new it was installed in 2011. I can get the serial number from it tomorrow.

 

[bilge rat jim]

I I would first suspect some water or other debris in the fuel system; let the engine rest for a cupla minutes and then drain the carb float bowl and see what comes out.

 

[Chef Shawn]

Before you run off and buy a fuel pump, disconnect coil wire(so motor won't fire) and disconnect fuel line to carb, have a buddy or wife hold a can to catch fuel and crank her over. If you have a good fuel flow you need to clean carb

 

[suwu7]

Good stuff guys Ill be sure to try this when I get a chance and let you know the outcome. This is my first inboard so Im still pretty new to all of this. Much obliged!

 

[alldodge]

Good stuff guys Ill be sure to try this when I get a chance and let you know the outcome. This is my first inboard so Im still pretty new to all of this. Much obliged!

Engine installed in 2011 but it has a carb. If it does have a carb and not a throttle body then it will not have an IAC. Look forward to seeing what the serial number is, that is if it did not receive an upgrade

 

[suwu7]

Here's a few pics of the motor.
http://i.imgur.com/2a22LOt.jpg
http://i.imgur.com/cNguZyB.jpg

Serial: 0M377098

Appears as though its getting a good fuel flow. I suppose that rules out the fuel pump possibility.

 

[Bt Doctur]

You have a carb and a mechanical fuel pump ,so start by replacing the fuel sep and fuel filters.

 

[alldodge]

Here's a few pics of the motor.
http://i.imgur.com/2a22LOt.jpg
http://i.imgur.com/cNguZyB.jpg

Serial: 0M377098

Appears as though its getting a good fuel flow. I suppose that rules out the fuel pump possibility.

What's telling you that you have good fuel flow?

Have you checked for spark at the distributer?

 

[rick3452]

Mine did something similar, would start for second and die... the lanyard switch was "off"

 

[airshot]

Three months or more of sitting idle does strange things to a boat motor. Sounds like mabey a clogged carb, but also time for a complete go thru....

 

[suwu7]

I bought a new fuel sep/filters yesterday that i'll be installing today. I pulled the fuel line at the carb and gave it a few cranks and thats where i determined gas is flowing fine. I have not checked the spark at the distributor yet. The lanyard switch is on, but the fact that its an older boat gives me the idea that maybe that switch isn't functioning like it should. Clogged carb was my second guess, but Im thinking its a problem with the air intake. Im not a mechanical genius by any means, but Im pretty sure when you give a carb throttle your "air flaps" in the carb are suppose to open, correct? If so, thats not the case I have here.