4.3LX BACKFIRES THROUGH CARB

[GRUBDIGGER]

1999 4.3 mercruiser. was running on the river at 4000 rpms. ran great until it backfired,sputtered and died. could not get it to re fire.removed all the lime green gas. changed the filter and added 5 gallons of new gas. wouldn't start. tried starting fluid and it tried to start but backfired and it flamed up. is this an ignition problem or could it have jumped time?

 

[NHGuy]

First off, Welcome to the forum!
Now, pour a spoonful of gasoline or a 2 second burst of carb cleaner down the carb throat and see how that does starting.it. BTW the battery should be fully charged or you should have jumper cables attached.
Starting fluid (ether) is not great stuff. use it a a last ditch effort.
If it runs & dies it's time to clean your fuel and fuel delivery system.

 

[jimmbo]

Lime green gas? How many hours on the engine?

 

[GRUBDIGGER]

not sure. sat for years. batteries are fully charged. poured gas into the carb. same result. may fire for two seconds and while cranking, it will backfire through the carb. it was running fine when we had it on the river. ran it for 10-15 min. it back fired and shut down. I am at a loss.

 

[Bondo]

Ayuh,.... Welcome Aboard,..... Sounds like that green gas gummed up the works, from the fuel tank to the carb,.....

A backfire through the carb is usually a sign of it bein' Lean,....
The fact that it fires if ya pour gas down the carb, reinforces that diagnosis,.....

 

[GRUBDIGGER]

well it wont fire up on starting fluid either. when it backfires, it will shoot flames out of the carb.

 

[flipbro]

Is it possible you jumped a tooth on timing or the distributer hold down bolt loosened off?? Just a guess. .

 

[GRUBDIGGER]

I will check it out.