hard to start, no gas in carb

[JLowe59]

Hello I have a 1979 AMF Crestliner 898 merc I/O. Mech fuel pump. I have to pump the throttle fast and furious about 10 seconds before she kicks over. She does kick over every time however. I was told that early carbs on these engines allow the gas to evaporate and new fuel has to be pumped and it can take that long before gas reaches the carb. So A)does that sound right? and B) if so can i put any kind of elec or bulb fuel pump between the pump and carb to prime it? Thanks.

 

[ron7000]

Re: hard to start, no gas in carb

A) no<br />B) probably not<br />the fact you can pump the throttle and it'll shoot gas into the intake, thanks to the accelerator pump on the carb, means there is gas in the carb. Pumping the throttle won't make the carb suck gas from the fuel tank.<br />Sounds like you need to set the choke, either adjust the linkage or manually hold it closed next time you go to start the engine cold and don't pump the throttle. If it kicks then you know it's the choke setting.

 

[skicat]

Re: hard to start, no gas in carb

The gas will indeed evaporate from the carb. The bowl will not fill untill you crank the engine. Try cranking the engine for 5 to 10 seconds, stop cranking, then move the throttle full forward a couple of times, then try to start.

 

[JLowe59]

Re: hard to start, no gas in carb

Thanks Skicat<br /><br />It does start everytime after 10 hard seconds (thats a long time cranking) I was hoping to find a better alternative. Any thoughts?

 

[Don S]

Re: hard to start, no gas in carb

It's going to take well over a week for the gas to evaporate. But if there is a leak in the carb, that could cause your problem, or a very weak accelerator pump.<br />May be time for a carb overhaul and inspection.

 

[JLowe59]

Re: hard to start, no gas in carb

Thanks Don<br />but i think that's my problem. 0ften due to kids sports, events, work and whatever I dont get on it that often. So after a 10 day period of non use is when I have the problem. I am reluctant to rebuild or anything else if it will happen anyway due to inactivity.<br />So some type of manual priming would make sense but I never saw a system that I could install.<br />Any thoughts?

 

[Gary H NC]

Re: hard to start, no gas in carb

Sounds like a carb rebuild for sure if setting the choke does not cure it.

 

[JLowe59]

Re: hard to start, no gas in carb

OK I feel like I am getting nowhere fast! My engine does start everytime. The only problem is that it takes 10 seconds of pumping the throttle to start it. I have had a few people tell me that the gas has evaporated from non use (two weeks) I can continue to do this but I am afraid the starter will wear out prematurly.(excessive cranking) The carb runs fine after she starts. I doubt a new carb is the answer. The choke is closed like it should be but there is no gas in the carb. my parts guy at the marine shop said he has heard of this problem but has yet to come up with a solution. any thoughts about getting gas into the carb would be appreciated. How long should it take to kick over an engine that has sat for two weeks?<br />Thanks<br />Jim

 

[DayCruiser]

Re: hard to start, no gas in carb

I have an 89 merc engine and it is fairly easy to start when sitting for a month or 2. Just when warmed up it was hard to start. Had to pump 10 times.. I found out it was the choke. The fuel pump should send enough gas into the carb to start no matter how long it sits if everything else is working properly.<br />Recently it wouldn't start at all and I found there was a short in the emergency shut off ignition switch. I thought it was the carb acting up again. You might look for a short in the ignition. A short that comes and goes

 

[Bondo]

Re: hard to start, no gas in carb

I have to pump the throttle fast and furious about 10 seconds before she kicks over.

Why would you Do That,..????....<br /><br />If the Carb Is Leaking,..... <br />Pumping the Throttle Violently for 10 Seconds Isn't going to Change a Thing,.... IF there's No Gas in the Carb.....<br />All that does,.. Is Wear Out the Throttle Cable........<br /><br />IF the Carb Is Dry,..... You could move the Throttle to WOT,.. Once,+ Just Once to set the Choke,+ then leave it at a High Idle setting,.....<br />Then you could Crank the motor over for the 10 Seconds,+ IF the Carb ISN'T the Problem,.....<br />The Motor would Start.........<br /><br />IF the Carb is Junk,+ the Choke Doesn't Work,........<br />Who Knows,...... Maybe Pumping the Snot out of the Throttle just Might be what Makes Your Boat Run............<br />Btw,.... A 10 Second crank is Not a Long Crank,......45 Seconds,+ Up is a Long Crank.......<br /><br />You Still haven't mentioned What Carb is on your motor,......<br />And,.... You're basing your Diagnosis on an old wifes tale that Somebody told you........<br />You haven't determined whether there's gas In the carb., or Not........<br /><br /><br />You been told Where to Look,+ Why,........<br />

OK I feel like I am getting nowhere fast!

I Gotta Agree with That............

 

[JLowe59]

Re: hard to start, no gas in carb

Thanks for all the responses and help. Aside from learning that I do not really know how carbs work. I think I learned the following.<br />1)Pumping the throttle does nothing.<br />2)The chock can be set by setting throttle at WOT.<br />3)Maybe nothing is wrong if she starts after a ten sec crank<br />4)I need a primer on how carbs work, specifically the choke and accelerator pump.<br /><br />If any one can point me to a site that I might be able to educate myself I would be appreciative.<br />Thanks Again for all the advice

 

[Gary H NC]

Re: hard to start, no gas in carb

All the choke does is close the top flap in the carb to give it a richer mixture when cold.<br />The accelerator pump is inside the carb and is like a small plunger that pumps the fuel out of the float bowl into the jets that spray the fuel into the carb.<br />Have you looked under the outside of the carb to see if any fuel could be leaking out? Any wet areas on the Intake manifold under the carb?<br />It does sound like its leaking down.A rebuild kit is around 20 bucks..

 

[Bondo]

Re: hard to start, no gas in carb

1)Pumping the throttle does nothing.<br />2)The chock can be set by setting throttle at WOT.<br />3)Maybe nothing is wrong if she starts after a ten sec crank<br />4)I need a primer on how carbs work, specifically the choke and accelerator pump.

1) Only IF there's No Gas In the Carb..... IF there IS gas in the Carb.,.... Pumping the throttle will Flood the motor........<br /><br />2) It's the Choke,+ it's Set by moving the throttle to WOT Once,+ returning the throttle to a lower setting......<br /><br />3) Ayuh,...... Correct......<br /><br />4) Ayuh,......<br /><br />5) You STILL Haven't told Us,...... WHAT Carb. do You Have...............

 

[Gary H NC]

Re: hard to start, no gas in carb

Bondo,This may take awhile...Is it a single,four barrel,rochester,holley???<br />

 

[JLowe59]

Re: hard to start, no gas in carb

Bondo, Thanks for being helpful.<br />It is a 4 bl Rochester w manual choke. So if I understand, WOT once and back off throtle. Crank engine till she runs. 10-15 seconds is acceptable.

 

[paulie0735]

Re: hard to start, no gas in carb

JL, based on what I have read in your posts to date I agree with some other posters here and suggest your carb is drying out between runs, this is not unusual, but it does seem that your fuel pump is taking far to long to fill the carb at cranking speed, a healthy pump will fill the carb with fuel in just a few revolution. In my opinion if you replace the fuel pump or install an electric pump you will in all likely hood solve your problem.

 

[DayCruiser]

Re: hard to start, no gas in carb

After getting a new choke all I have to do is move the throttle to WOT once(about half way) and leave it there and it would start right up(Merc carb) Before, I had to floor it and keep pumping.<br />First start up it would start right up at the half way point. But after you ran that motor short while then you would have to pump it.

 

[Bondo]

Re: hard to start, no gas in carb

Originally posted by JL Crestliner1979:<br /> Bondo, Thanks for being helpful.<br />It is a 4 bl Rochester w manual choke. So if I understand, WOT once and back off throtle. Crank engine till she runs. 10-15 seconds is acceptable.

You've Still got to figure out whether you Actually Have a Carb or Fuelpump Issue........<br /><br />When All is Right,.......<br />Ayuh,....<br />That's How it should be Started..........<br /><br />Btw,.... That's supposed to be an Automatic Choke,.... That's the Reason for the Single Pump of the Throttle,.. To Set It.....<br />A Manual Choke has a Cable,+ a Handle you'd be regulating to keep it running.......<br /><br />You do of course Check the engine Oil,+ Do a Sniff Test,....... Before you proceed to the Helm Anyway,..... Right,..??........