96' Merc 454 hard starting
#12
Ok, then next time no pumping but put the throttle to wide open and crank it over. Be ready to pull back the stick quick when it fires. Then buy a decent holley carb.
#13
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Joined: Dec 2003
Posts: 699
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From: central NY
Yep. Could be something other than a carb problem. Your cap and rotor could be the problem. How old are the plugs and wires? When was the last time timing was checked? How about the fuel water seperator? I'd get the obvious/cheap stuff out of the way 1st.
Last edited by Kidnova; 08-24-2009 at 07:30 PM.
#15
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Joined: Jun 2004
Posts: 334
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From: Md
I agree with Purple. Re-connect the damn choke. It's there for a reason. There's nothing inherently wrong with the Weber carb (Carter AFB) or the chokes they came with. They work very well and are very easy to tune, especially compared to a Holley.
On the 454 give it a pump or two and pull the throttle back to closed until the choke plate also closes (once you fix it) and the motor will start. Do not hold the throttle open.
On the 454 give it a pump or two and pull the throttle back to closed until the choke plate also closes (once you fix it) and the motor will start. Do not hold the throttle open.
#16
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Joined: Mar 2008
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In fact I really dislike the Edelbrock carb as it has been a real challenge to tune. Actually swapping jets and needles is easy, even on the water, but getting it performing correctly has been nearly impossible. I decided to just rebuild my original Quadrajet 795 and put that back on, and the engine is night and day differenct- better power and better fuel economy. Following the formulas indicates I need 730 cfm so I felt the Edelbrock would be sufficient. Obviously the Rocheter is far more complicated and harder to tune, but it seems to work better over the entire rpm range. That said, I prefer EFI overall.
#17
If the engine is flooded from the bowls leaking, you will only make things worse by pumpng the throttle.
#18
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Joined: Jun 2004
Posts: 334
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From: Md
Of course it would. I simply assumed a hard start problem was most likely only to be the defeated choke. Lots of things could be wrong and there could be multiple problems.
I don't understand the problems people have with this carb. It's such a simple unit. Getting the main and secondary jets and metering rods exactly right have nothing to do with hard starts and the choke is so f'in simple.
Check that the float levels are correct and the needles are working.
One thing I found helpful was you can purchase spring-loaded needle and seat assemblies from Eldebrock. Designed for off-road apps in the 750 street carb they can cut down on minor flooding issues on performance boats as well. They are cheap and easy to install on the marine Weber.
Last edited by NightHawk; 08-26-2009 at 02:30 AM.
#19
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Joined: Mar 2008
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Of course it would. I simply assumed a hard start problem was most likely only to be the defeated choke. Lots of things could be wrong and there could be multiple problems.
I don't understand the problems people have with this carb. It's such a simple unit. Getting the main and secondary jets and metering rods exactly right have nothing to do with hard starts and the choke is so f'in simple.
Check that the float levels are correct and the needles are working.
One thing I found helpful was you can purchase spring-loaded needle and seat assemblies from Eldebrock. Designed for off-road apps in the 750 street carb they can cut down on minor flooding issues on performance boats as well. They are cheap and easy to install on the marine Weber.
I don't understand the problems people have with this carb. It's such a simple unit. Getting the main and secondary jets and metering rods exactly right have nothing to do with hard starts and the choke is so f'in simple.
Check that the float levels are correct and the needles are working.
One thing I found helpful was you can purchase spring-loaded needle and seat assemblies from Eldebrock. Designed for off-road apps in the 750 street carb they can cut down on minor flooding issues on performance boats as well. They are cheap and easy to install on the marine Weber.


