priming the carb

[carrotsnapper]

I have a 1980 Cobalt with a 260 merc I/O and a 350 V8. I have found I need to prime the carberator when I haven't run it for a few days. Is this common? If I replace the fuel pump, will the problem go away? My Sweetheart hates it (she had someone prime her car when she was young and it backfired and started the engine on fire) I would like to fix this problem, but I'm no shade tree mechanic and could use a little advise.

 

[watermellonI]

Re: priming the carb

Hey Carrotsnapper
It s a carb

How are you "priming" it?

Put the shift control in neutral(so the drive doesn t engage), TURN THE BLOWER ON AND SNIFF pump the shifter forward app 1/3 forward 2 times and then turn the key.

 

[watermellonI]

Re: priming the carb

Yes its normal, the carb dries out after sitting, it s supposed to. The fuel pump only works when the engine is "on" or turning over.

If the motor runs fine after your initial start, your pump is probably fine.

 

[tashasdaddy]

Re: priming the carb

that motor is suppose to have an automatic choke, it may not be working, get a mech to look at it.

 

[Chris1956]

Re: priming the carb

Carrot, My I/O carb motor started doing this after a few years, for some reason. A workaround is to put the controller in "throttle only" mode, and pump the throttle while cranking the motor. Usually about 10 sec of cranking and pumping will refill the carb and start the motor. There is no need to pour gas into the motor.

 

[Maclin]

Re: priming the carb

I hope by "priming" you mean you are actually getting gasoline into the fuel bowls and not just pouring it down the throttle body throat of the carburetor. Pouring it down the throat is a good way to cause a backfire during cranking and lite off all that gasoline you just put into the intake manifold.

It is hard to get gasoline into the fuel bowls on a Marine carb, the fuel vents are curved up and over and down over the throat. On car carbs you could manage to spill some ever so slowly thru the vents and this would let the carb act normally until the fuel pump had a chance to "catch up" and fill the lines and eventually reach the fuel bowls.

Carbs have a definite way to start up after a longer layup. Waiting for the fuel pump to fill the lines and then the carb "naturally" is safest.

Try pumping the throttle just before starting then a couple of times while cranking. This will squirt any residual fuel left in the bowls and may allow it to catch. If that fails or it starts then dies then just crank 5-10 seconds and stop, then pump the throttle a couple of times then crank again. Repeat the 5 second crank cycle with a short 10-15 second wait in between.

 

[WanabeBoater]

Re: priming the carb

I agree with the pumping of the throttle..it gets aggrivating initially but you'll get used to it. I used to wait until I got the boat in the water before I started it and sometimes I would hold up everyones launch waiting for my carb to fill. I would be mad, then my wife gets mad and then the kids get quite. But after awhile, you'll master it and shake your head at the next guy trying to prime his lines. LOL

 

[WanabeBoater]

Re: priming the carb

.....Next purchase, Multi Port Injection!!! Yeah

 

[Coors]

Re: priming the carb

Only after sitting a couple of days, 2 throttle pumps should start it.
Is it a quadrajet? They can empty the bowls internally, if leaking.

 

[carrotsnapper]

Re: priming the carb

If I may respond to your questions and suggestions. I do pour gasoline down the throat of the carberator. It starts easily that way. I do it only before I leave the house and haven't ever done it in the water. I have tried pumping the throttle and and turning on the ignition to let the fuel pump start pumping. It never has started for me that way after sitting for a week or two on my grass. I will try your suggestions again this spring when I fire her up to see if I can get it to start that way. I always start her up at home so I don't have to deal with a stalled engine on the ramp. I have one of those jump starters that you buy at Costco that I have let many other guys use, but never had to use myself on the ramp. To me, ramp etiquette, requires that the boat be loaded with the gear and family and the motor be primed and ready to run as quickly as possible to get out of the way for the next guy. I liked the idea the maybe the choke isn't functioning properly and will certainly check on that possibility. I haven't ever had trouble on the lake with the motor or starting. I appreciate all your comments and hope that others may have been helped along the way. Thanks. Mark

 

[watermellonI]

Re: priming the carb

Great Ramp Etiquette

 

[WanabeBoater]

Re: priming the carb

Good Luck!!!

 

[Coors]

Re: priming the carb

Carb needs rebuilding acellerator pump + other stuff ain't working.

 

[Boatist]

Re: priming the carb

My boat does the same thing. In the summer my boat is in the sun and covered and it gets 140 plus every afternoon. If it been sitting for more than 2 weeks it can take a minute or more to get enough fuel pumped into the carburator for the accelerator pump to work. After that it is normal. My solution is first trip in the spring I always start at home on Muffs. The long crank has the advantage of pumping some oil thru the bearings and getting oil pressure before the motor starts.

After the first time in spring I will start at the ramp. If everything ready when you back down then the 1 minute will not delay anyone.

 

[Mischief Managed]

Re: priming the carb

An electric fuel pump would be a simple solution. I would not pour gas down the throat of the carb.

http://www.amazon.com/gp/product/B000CMJNEU

 

[Coors]

Re: priming the carb

An electric pump is masking the problem, not fixing it.

 

[Maclin]

Re: priming the carb

It read to me like he has an electric pump already in post#10......

"I have tried pumping the throttle and and turning on the ignition to let the fuel pump start pumping."

Turning on the key to start the fuel pump pumping only works if there IS an electric fuel pump, and the key is in the Cranking position. I would be surprised on that year that there is an electric pump, maybe Cobalts did that or maybe one was added on later. I hope carrotsnapper can verify whether he has one or not. The reason I doubt it has one is the fact that he can only get gas into the carb by pouring the gas into the engine and starting it, then once the engine catches then the mechanical fuel pump on the engine will pump better and faster and fill the carb sooner. An electric fuel pump will pump at about the same rate with the engine cranking or while it is running. There also has to be an oil pressure switch and a cranking bypass circuit for an electric fuel pump to be "legal" and safe.

And regarding pouring the fuel down the carb throat then leaving it in there for the trip to the lake, well I like that idea even less because of the cylinder washing that will happen as the gasoline works the oil film off of the cylinder walls.

In any event, an electric fuel pump will fill the carb without the engine running usually only if the key is turned to the cranking position. You may be able to hear it, but may not over the cranking noise. As I mentioned before there should be an oil pressure cutoff switch that will stop the electric fuel pump from pumping if the engine dies. There is also a bypass circuit that will run the fuel pump while cranking. If the fuel pump kicks on with the key in the on position without the engine running then I would think something may not be wired correctly or a component has failed. That is a dangerous situation, engine dead, ignition on, fuel pump pumping and carb overflowing or fuel line breaks or leaks or......

 

[Coors]

Re: priming the carb

Ignored because he shouldn't have one.

 

[Mischief Managed]

Re: priming the carb

An electric pump is masking the problem, not fixing it.

Wouldn't that depend on the cause of the empty fuel bowl? If it's evaporating over a few day's time, there's not much one can do to "fix" it. If it's leaking, that's another matter...

 

[Coors]

Re: priming the carb

I.ve never heard of it all evaporating in 2 days.