Mercruiser 5.7 crank but want start

[Wellcraft1996]

I have a 4bbl carb. 5.7L and it will crank but want start. After new coil, distributor cap, still know start. Checked spark plugs and both rear plugs 7 and 8 were wet with gas and black smuck. The other plugs were covered in just black smuck could that keep engine from starting. Also recently had carb rebuilt and if think its delivering to muck fuel in carb. Can carb air/fuel mixture be adjusted with engine not running?

 

[alldodge]

If carb is flooding the motor won't start.
Are you getting spark?
What's the motor serial number?

 

[Wellcraft1996]

If carb is flooding the motor won't start.
Are you getting spark?
What's the motor serial number?

engine serial number is OF414565. Engine I dont think it fires in the cylinder 7 and 8. Those cylinder spark plugs were really dripping with gas and black carbon

 

[Wellcraft1996]

engine serial number is OF414565. Engine I dont think it fires in the cylinder 7 and 8. Those cylinder spark plugs were really dripping with gas and black carbon

After carb was rebuilt, I think shop didn't set fuel and air mixture screws at all and too much fuel is going into carburetor.

 

[alldodge]

Mixer screws won't cause it to flood and not start, it won't idle very well.

Run through the TBV troubleshooting "exactly" as shown to test for spark. When it says to rapidly ground the wire several times fast, that's what ha to be done

 

[Wellcraft1996]

Mixer screws won't cause it to flood and not start, it won't idle very well.

Run through the TBV troubleshooting "exactly" as shown to test for spark. When it says to rapidly ground the wire several times fast, that's what ha to be done

View attachment 368242

Mixer screws won't cause it to flood and not start, it won't idle very well.

Run through the TBV troubleshooting "exactly" as shown to test for spark. When it says to rapidly ground the wire several times fast, that's what ha to be done

View attachment 368242

 

[Wellcraft1996]

The old girl started up and eventually after some ruff idling and rattling/knocking noise the engine smoothed out and ran like a champ. Don't know what the knocking noise was, but it went away.