Engine wont start unless you put gas in carb

[kdmiller8251]

Hey all Quick question<br /><br />I got a mercruiser 5.7 Alpha I 1990 with a rochester 4bl on it.. I can not get the engine started unless I prime carb with Gas. Then runs fine all day and starts fine... Any ideas....<br /><br />Thanks<br /><br />Tallman

 

[f_inscreenname]

Re: Engine wont start unless you put gas in carb

How long do you leave it sit befor you use it again?

 

[kdmiller8251]

Re: Engine wont start unless you put gas in carb

Overnight

 

[f_inscreenname]

Re: Engine wont start unless you put gas in carb

I would start with the fuel pump they are pretty cheep. Alot cheeper then a carb.

 

[daveswaves]

Re: Engine wont start unless you put gas in carb

Sounds more like the accelerator pump on the carb, if the fuel pump was kaput you would not run at high speed, you would starve for gas. Carb kits have a new pump in them. You can check it fairly easily, with the motor off and ign off, have someone move your throttle lever to full fast and back to neutral again while you look down the primary barrels of the carb, you should see gas squirt in, if not, the pump or the linkage is bad. You are simply replacing the pumps function when you prime through the carb. After the engine is running a bad pump may show up as a BOG when you accelerate fast....might not.

 

[galaxy225]

Re: Engine wont start unless you put gas in carb

hey tallman now it is pump maybe.....cant win at all.......well iam in the same boat here i have a guy coming tomorrow look at it i think i might have to put a waterpump kit in mine where the lower unit is........did you read my post that you replyed in......i made a joke inthere that maybe you have liked.......i know this your post i have a question for you if you would to answer....you know my boat is out of water right now...would that make a differents if my tilt was up and she was not getting anywater or that might be the impeller she not getting any water at all..........i was thinking about doing it my self i am un sure afraid of messing up......any ways sorry about the post here....good luck finding the answer......

 

[kdmiller8251]

Re: Engine wont start unless you put gas in carb

Yeah sound like it could be pump... I had guy work on carb few weeks back and kind of since then its been having problems....Story of my boat.. Probolems problems.. HA HA<br />Someday I may get it running and not overheating.....

 

[galaxy225]

Re: Engine wont start unless you put gas in carb

thanks tallman.........goodluck

 

[flashback]

Re: Engine wont start unless you put gas in carb

re-build the carb or buy a new one, I spent about 400.00 on a new AFB (made by carter) and it works great. what ever brand you use, make sure it can deliver at least 600 cfm....good luck

 

[torxdrive]

Re: Engine wont start unless you put gas in carb

is the chock closing if not that will be one of the probs

 

[MGuckin]

Re: Engine wont start unless you put gas in carb

It doesn't sound like a fuel pump problem at all. If the fuel pump was at fault, starvation would not only effect starting. It would effect normal operation which you say if fine.<br />Sounds like the accelerator pump. <br />Rochestors are great carbs until they mess up. Very fussy on rebuilding reassembly.<br />If your budget allows, replace it; if not, do a complete rebuild very carefully.

 

[kdmiller8251]

Re: Engine wont start unless you put gas in carb

Yeah its the pump... Its stuck. I can see it..<br />Thanks all<br /><br />tallman

 

[Walter]

Re: Engine wont start unless you put gas in carb

Pump is stuck? Which pump? <br /><br />I'm betting it's the accelerator pump on the carb, right? I screwed up the plunger on my Roch carb when I rebuilt it...dumb mistake but easy to do for a rookie that had never done one before. I know now!<br /><br />Walt