3.0 mercruiser ran for 5 min good. Then Just died?

[ilove2fixx]

hi gang, well this boat is giving me a hard time. I thought i had her fixed but i guess not. So today i decided to do some adjustment to have the 3.0 running smooth, to my amazement she fired right up! She ran good, rpm pretty high around 1500-1800 but she ran fine for about 5 min then i went to lower the mixture screw on the side and lowered the rpm to around 1000 but was running rough. Then she died. she wont start unless i give it a couple pumps? then dies again.. I dont think the carb is the issue because she ran good for like 5 min? It was untill i messed with the mixture screw.. But i tried to adjust the screw back to what it was when she ran but still hard to start and keeps dying.

 

[ilove2fixx]

i do notice some noises like tinging after trying to start her up and goes away after 10 seconds? I dont know if its the starter selenoid or what. But heres a video. It happens everytime after attempting to run or runs for a second and dieas

 

[todhunter]

Have you checked your timing?

Don't rule the carb out. You could have some trash that got moved around while it was running good.

Do you have a water/fuel separator? If so, pull it off and pour the contents into a clear glass. How does it look?

 

[Bondo]

she wont start unless i give it a couple pumps? then dies again.

Ayuh,..... I'm thinkin' ya got a fuel supply issue,.....

No idea what the clicking noise is,..... it's a new one for me,....

 

[nola mike]

Ayuh,..... I'm thinkin' ya got a fuel supply issue,.....

No idea what the clicking noise is,..... it's a new one for me,....

Sounds heat related/expansion noises to me. And there's a kid there as well. Usually that drowns out any other noises...

 

[Rick Stephens]

Idle circuit is plugged up.

 

[Bondo]

Sounds heat related/expansion noises to me. And there's a kid there as well. Usually that drowns out any other noises...

Ayuh,.... I can't argue that, But,....

It doesn't appear that he ran it long enough for such a severe overheat to happen,....
But hey,.... Maybe,....

 

[achris]

Pull the fuel pump. That noise is the lever tapping on the cam. You've got a (fuel) valve the wrong way around or something else inside is not right. That also accounts for it running for 5 minutes (one carb full of fuel) and then not wanting to go again...

Chris....

 

[nola mike]

Pull the fuel pump. That noise is the lever tapping on the cam. You've got a (fuel) valve the wrong way around or something else inside is not right. That also accounts for it running for 5 minutes (one carb full of fuel) and then not wanting to go again...

Chris....

After the engine's stopped?

 

[nola mike]

After the engine's stopped?

Pull the fuel pump. That noise is the lever tapping on the cam. You've got a (fuel) valve the wrong way around or something else inside is not right. That also accounts for it running for 5 minutes (one carb full of fuel) and then not wanting to go again...

Chris....

Oh, fuel flowing backward through the pump?

 

[achris]

Oh, fuel flowing backward through the pump?

Now you're getting it.

 

[ilove2fixx]

Have you checked your timing?

Don't rule the carb out. You could have some trash that got moved around while it was running good.

Do you have a water/fuel separator? If so, pull it off and pour the contents into a clear glass. How does it look?

i rebuilt the carb twice im pretty sure its clean , ill check the fuel filter tomorrow.

 

[ilove2fixx]

Sounds heat related/expansion noises to me. And there's a kid there as well. Usually that drowns out any other noises...

yeah thats my daughter.. maybe it is normal expansion noises

 

[ilove2fixx]

Sounds heat related/expansion noises to me. And there's a kid there as well. Usually that drowns out any other noises...

yeah thats my daughter.. maybe it is normal expansion nois

Idle circuit is plugged up.

in the carb? i really dont wanna take it apart for the 3rd time , that damn bolt in the back right is a pain in the a$$!

 

[ilove2fixx]

Pull the fuel pump. That noise is the lever tapping on the cam. You've got a (fuel) valve the wrong way around or something else inside is not right. That also accounts for it running for 5 minutes (one carb full of fuel) and then not wanting to go again...

Chris....

But the boat sat for over a month and she fired right up first try, and ran for like 5 min but idle was high, then i adjusted the mixture screw it lowered the rpms, then it was running ok .. I went to give it throttle and it died... After that itll only run for a couple seconds if i pump the throttle couple times..

 

[achris]

But the boat sat for over a month and she fired right up first try, and ran for like 5 min but idle was high, then i adjusted the mixture screw it lowered the rpms, then it was running ok .. I went to give it throttle and it died... After that itll only run for a couple seconds if i pump the throttle couple times..

You asked for ideas, I'm giving you my ideas...

A) You shouldn't be using the mixture screw to lower the revs, use the idle speed screw.

B)The engine running for 5 minutes, then only for a few seconds when the throttle's pumped is consistent with a fuel pump failure.

Not much else I can say....

Chris........

 

[Rick Stephens]

Idle mixture screw has a specific place and method to be, to set the mixture (not the speed). If you cannot lower RPMs by adjusting the idle speed screw then either the throttle cable linkage is too tight, or you have an intake leak. The Mercruiser Service Manual is the correct place to see steps on correctly setting your carburetor up.

 

[ilove2fixx]

Idle mixture screw has a specific place and method to be, to set the mixture (not the speed). If you cannot lower RPMs by adjusting the idle speed screw then either the throttle cable linkage is too tight, or you have an intake leak. The Mercruiser Service Manual is the correct place to see steps on correctly setting your carburetor up.

could be the throttle cable becuase i havent adjusted it and it is tight. i forgot about that. I hope its not the fuel pump

 

[ilove2fixx]

You asked for ideas, I'm giving you my ideas...

A) You shouldn't be using the mixture screw to lower the revs, use the idle speed screw.

B)The engine running for 5 minutes, then only for a few seconds when the throttle's pumped is consistent with a fuel pump failure.

Not much else I can say....

Chris........

i really hope its not the pump. I mean how is that possible it ran good for a while UNTIL i gave it gas then it died? Anyway to test out the pump ?

 

[ilove2fixx]

so the fuel pump in the gas tank or is the one on the block it? Ill take out the filter and see the condition.