Mercruiser 3.0 litre stalls at idle with new carburetor

[davidvo68]

Hello all,
Sorry for being the newbie trying to solve the engine starting issue.
I have a 2000 Mercrusier 3.0 inboard engine.
I had replaced new battery, cleaned and rebuilt the fuel pump, replaced carburetor, replaced oil and filter.
Two issues:
First issue is now there are no fuel coming into the fuel pump so I decided to connect the fuel pump intake to an external tank with an inline pump. This temperately solved my fuel issue.
Second issue is that I can't start the engine when gear at neutral unless I pushed in the advanced throttle button and shift the gear handle backward or forward about 30 degree from the neutral position. The engine runs smooth at around 1100 rpm.
I watched some troubleshoot YouTube videos with no success.
I hope this forum will have some experts to help out.
Thank you in advance and sorry for being a newbie to the boating world.

 

[davidvo68]

 

[Scott06]

Hello all,
Sorry for being the newbie trying to solve the engine starting issue.
I have a 2000 Mercrusier 3.0 inboard engine.
I had replaced new battery, cleaned and rebuilt the fuel pump, replaced carburetor, replaced oil and filter.
Two issues:
First issue is now there are no fuel coming into the fuel pump so I decided to connect the fuel pump intake to an external tank with an inline pump. This temperately solved my fuel issue.
Second issue is that I can't start the engine when gear at neutral unless I pushed in the advanced throttle button and shift the gear handle backward or forward about 30 degree from the neutral position. The engine runs smooth at around 1100 rpm.
I watched some troubleshoot YouTube videos with no success.
I hope this forum will have some experts to help out.
Thank you in advance and sorry for being a newbie to the boating world.

Does the choke close ? It is normal on a carbureted engine to pump the throttl forward Once or twice this sets the choke closed and squirts some fuel in via the accelerator pump.
would start with following
check compression
check condition of ignition components
did you set the ignition timing? Adjust the idle mix and speed on carb?
trace back the fuel line to the tank must have a split or blocked hose or tank pick up.

 

[Rick Stephens]

Scott gave you a good list. My first thought reading your post was that you need to set idle mixture and idle speed. Those are done together. The Mercruiser Service Manual is a most necessary tool to own if you are going to work on your own Merc IO. Absolute must. It has step by step procedure for setting idle mixture and RPM. Buying a new carburetor does not allow skipping that because you think it is all ready to rock and roll. New carb still has to be set up.

Then we go back to Scott's post. Each and every item is essential basics to getting up and running. Sounds like you have a fuel line leak between tank and pump. Finding that is not always so fun. We'll help with whatever we can.

 

[Scott Danforth]

agree with above. New does not mean its adjusted/tuned to your motor

 

[davidvo68]

Hello all,
Sorry for being the newbie trying to solve the engine starting issue.
I have a 2000 Mercrusier 3.0 inboard engine.
I had replaced new battery, cleaned and rebuilt the fuel pump, replaced carburetor, replaced oil and filter.
Two issues:
First issue is now there are no fuel coming into the fuel pump so I decided to connect the fuel pump intake to an external tank with an inline pump. This temperately solved my fuel issue.
Second issue is that I can't start the engine when gear at neutral unless I pushed in the advanced throttle button and shift the gear handle backward or forward about 30 degree from the neutral position. The engine runs smooth at around 1100 rpm.
I watched some troubleshoot YouTube videos with no success.
I hope this forum will have some experts to help out.
Thank you in advance and sorry for being a newbie to the boating world.

Thank you so much. I will follow your list Scott06.
Rick and Scott D. thank you and I will update back here with progress.
I don't have an idea on how to check compression but I will find out from YouTube. This is great.

 

[Rick Stephens]

I think the service manual even tells how to do a compression check.

 

[Scott06]

I don't have an idea on how to check compression but I will find out from YouTube. This is great.

simple to do just a simple sanity check before you get too far in that the mechanical condition of the engine is ok

you tube or manual will have procedure to follow

 

[havoc_squad]

Spend some time to read the OEM service manual in depth and post your remaining questions to fill in the gaps.

Do not shy away from asking questions that help you determine if you accurately understand a particluar subject/system/procedure.

The worst thing you can do is get in a huge hurry trying to meet some deadline as a DIY fixer who doesn't have the training, knowledge, and experience to work fast on these things.