1994 5.7L Weber carb

[searay320]

My 1994 Celebrity 230 5.7 L mercruiser mercathode ignition starts and runs fine but leaves a black unburnt fuel line on the hull, and it loads up and misses after a couple hrs of running,,backfiring thru the carb and missing,,but doesn't idle too bad..timing is good and adjusted carb,,where else to look?

 

[nola mike]

My 1994 Celebrity 230 5.7 L mercruiser mercathode ignition starts and runs fine but leaves a black unburnt fuel line on the hull, and it loads up and misses after a couple hrs of running,,backfiring thru the carb and missing,,but doesn't idle too bad..timing is good and adjusted carb,,where else to look?

How did you adjust the carb? At the very minimum you need to check your float levels and make sure your needle valve is closing. But a rebuild is probably in order. Also need to check your fuel pressure.

 

[searay320]

adjusted the carb to manual specs and timing light with RPMs at 650. Its not hard to start cold, but after warmed up and running it acts up. thanks!

 

[nola mike]

adjusted the carb to manual specs and timing light with RPMs at 650. Its not hard to start cold, but after warmed up and running it acts up. thanks!

Again, float level and drop are part of the adjustment. If you're running that rich it probably isn't the idle adjustment unless that's where you do most of your boating

 

[achris]

Weak spark, old spark plugs...

 

[nola mike]

Weak spark, old spark plugs...

Yup, I jumped to fuel without reading closely and noticing the misfire

 

[searay320]

I think I will pull the top off and check everything and get a kit while I am at it..
what if the primary jets were .098 instead of .101 and the secondary jets were .101 instead of .092...thats what im seeing. . the book spec calls for .101/.092 would this cause rich fuel mix

 

[Scott06]

I think I will pull the top off and check everything and get a kit while I am at it..
what if the primary jets were .098 instead of .101 and the secondary jets were .101 instead of .092...thats what im seeing. . the book spec calls for .101/.092 would this cause rich fuel mix

None of that would affect idle, but those thise jets it would be slightly lean when running on the primaries and very rich when the secondaries kick in

in my opinion start with the basics, clean and rebuild the carb, set the float level, go through the ignition components cap rotor plugs and wires, set tge idle mix and speed and see how it works.

 

[searay320]

Thats what Im doing...
Thanks

 

[Scott06]

Thats what Im doing...
Thanks

One last thing check the contents of the fuel filter for anything but clean gasoline.

 

[Lou C]

Those symptoms suggest an auto choke not opening up all the way. These have an electric choke and need a constant 12v for it to stay open

 

[searay320]

Those symptoms suggest an auto choke not opening up all the way. These have an electric choke and need a constant 12v for it to stay open

Thanks. While I’m waiting on the kit i will check vola