4.3 cold starts

[t8km]

just bought a used 1996 boat with 4.3 and 2 bbl. having a very hard time starting when it's cold. tried no choke, tried choke, tried pumping it then cranking. tried cranking and pumping all with no luck. once i prime it with fuel it starts up fine. after warmed up it starts great. i'm sure i'm not getting fuel when pumping the throttle. should i be able to pump fuel without cranking motor? the carb. filter is clean. any help would be appreciated.

 

[12Footer]

Re: 4.3 cold starts

If u maually open the throttle up,and see no gas spray in the carb, the accilerator pump is bad.<br />There might also be a tiny filter inside the<br />fuel line,right where it goes into the carb.<br />Is the inline filter clear?<br />If so,it should visably move when the engine is cranked.<br />My PenYann (inboard 350) had a metal filter that gave me grief. I put one of those glass<br />jobbies in there,and bought a pack of filter elements,it clogged up often,but was easy to change-out in the middle of nowhere

<br />Godd luck,and let us know what u find,T8Km.<br /><br /><br />------------------<br />the Early bird get's the worm...So, he don't have to stop for bait.

 

[12Footer]

Re: 4.3 cold starts

No edit feature got me AGAIN

<br />I wrote; "if the filter is clear, it should move" or some such rot..... I meant the fuel inside the filter would move.<br /><br /><br />------------------<br />the Early bird get's the worm...So, he don't have to stop for bait.

 

[t8km]

Re: 4.3 cold starts

getting my problem narrowed down a bit but not completely. after priming the motor (gas down carb) i got the motor to run and run good. the next night i pumped the carb back at the linkage so that i could see it (pumped fine, accelerator pump worked) cranked it over, ran for about 10 seconds then died. went back to the motor, pumped it again this time no fuel when pumping. at this point i am thinking fuel pump. checked voltage at fuel pump it looks good. take the fuel line off at the carb crank the motor over and i get plenty of fuel. checked the screen inside the carb and it looks good. right now i'm kind of baffled. the only thing i can come up with is when the motor is running (after priming) that maybe the extra voltage is helping me get better fuel pressure out of the pump. does this sound stupid or is it possible.

 

[ODDD1]

Re: 4.3 cold starts

T8km, it sounds like your fuel system is draining out after you turn the motor off....if it has only been a little while since the motor has been turned off, it will start an run..but after an overnight sit it will dry out. could be a bad check valve in fuel pump or a syphon valve on top of the fuel tank thats got junk caught in it.

 

[t8km]

Re: 4.3 cold starts

thanks for the help. put a pressure gauge on fuel line with a clear hose on it so i could see if the fuel was draining back. had 6 #'s pressure at the guage (jumped the pump to the battery to keep it on a while) as soon as i took the jumper wire off pressure droped to nothing. looked at the clear line this morning after sitting over night and sure enough no fuel in the line. called mercruiser tech. help and they told me my pump has check valves that are probabley stuck open, replacement pump does not have check valves anyway (they rely on check valve at the tank) so now i'm try to find a inline check valve for 3/8 line that will not take much vaccuum to open. can't find such a critter at any of my auto parts stores. anyone have a source??

 

[12Footer]

Re: 4.3 cold starts

Replace every stick of fuel line first. It may be as simple as a pinhole leak,allowing air into the fuel line,thus draining it overnight.<br />A water seperator installed as close to the fuel pump as possable, would eliminate the symptoms at any rate. It would operate off the fuel in the bulb until the fuel pump catches-up, and also provide the beifit of seperating water in the fuel.<br />Just thinkin out loud here, so good luck at gettin her going.<br /><br /><br /><br />------------------<br />"Honey,have you seen my boat keys? Honey? Where are you?"

 

[12Footer]

Re: 4.3 cold starts

EDIT EDIT..."I said as close to the pump"....I meant "as close to the carb" as possable.<br /><br /><br />------------------<br />"Honey,have you seen my boat keys? Honey? Where are you?"

 

[t8km]

Re: 4.3 cold starts

sounds like mercruiser had lots of problems with this fuel pump with internal check valves. talked to merc rep today and they suggested checking to see if i had a check valve at my tank. i do not. found a anti-siphon valve that has 3/8" barb on one end and 1/4 male threads on the other, this will allow me to attach right at the tank and will keep fuel in the line from the tank to the carb. have not installed yet but think it will take care of it.

 

[sony2001]

Re: 4.3 cold starts

Thanks guys: I've been living with that problem for quite sometime, rationalizing it<br />as my antitheft system.<br /><br />Are you from Tennesse? NO! Oh, you are the<br />only ten I see here.<br /><br />------------------

 

[t8km]

Re: 4.3 cold starts

forgot to add--have a fuel seperator factory installed just in front of fuel pump.