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Old 01-13-2010, 09:53 PM   #1
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1990 wrangler hard start (carb)

I have a 1990 Wrangler 4.2L (weber carb) that takes about 4 cranks to start with cold engine. I replaced the fuel pump (mechanical) and fuel filter, plugs, wires. It seems like the fuel does not reach the carb?? I pump the gas 3x before starting....still no go. Once it starts up it runs great right away. If it sits for a day, it goes back to 4 long cranks again. Any ideas??

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Old 01-13-2010, 10:19 PM   #2

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Choke working?

Nothing is foolproof to a sufficiently talented fool.
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Old 01-13-2010, 10:41 PM   #3

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Have you done the nutter bypass yet if not that is your first thing to do.
Then set the timing at 8 degree's.
Make sure your choke is working and if it is your carb is most likely a little lean
and a lean mixture will make for hard cold starts.
If you have no stumbling or rough running once warm i would say you dont have vacuum leaks.
and with the weber carb you only need 3.5 pounds of fuel pressure so i assume you have a regulator for that,

But first do the bypass , set timing , new plugs, adjust air mixture and that should do it.

give me a call if you need more help

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Old 12-10-2014, 11:51 AM   #4
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Just bought my daughter a 1990 Islander I6 engine. It starts fine in warm weather but anything under 35F it cranks & cranks then starts after 5 minutes.
I'm not savy with stuff like this and hoping its an easy fix. Any suggestions?
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Old 12-10-2014, 02:38 PM   #5
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What happens is when it sits the fuel drains out of the bowl and it takes a few cranks for the fuel pump to fill it. Then it will start. It's a common issue. If my 89 4.2 sits for a day it's fine. If it sits 2 or more it has to crank more and then it will start. Once it starts it goes right on a high idle and the carb functions properly. The carb worked perfect for a few years after a rebuild and then the seals slowly allowed fuel to leak. It happens with all of those carbs, some leak more and some less. The only way to fix it is to re-seal the carb./ rebuild it or you can replace it if it progressively gets worse.
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Old 12-10-2014, 02:50 PM   #6
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Originally Posted by JD082570 View Post
Just bought my daughter a 1990 Islander I6 engine. It starts fine in warm weather but anything under 35F it cranks & cranks then starts after 5 minutes.
I'm not savy with stuff like this and hoping its an easy fix. Any suggestions?
In this case most likely your choke isn't working. Loosen, but don't remove the cap on the auto choke and see if you have a broken spring. If not try adjusting it to 1 notch rich and see if that works. If not, you could have an issue that's internal to the carb which is causing the choke not to set. Check the mechanism and see if it will manually set, meaning the carb plate closes when cold. It should close but not all the way. If it does it might only need an adjustment. If it doesn't close at all, the internal auto choke mechanism might have failed. You can always add an electronic choke. They're not expensive. Or, you can get a manual choke kit, attach it to the carb. and control it manually which you can hook up under the dash.
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Old 12-10-2014, 06:44 PM   #7
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Also the fuel filter placement can cause hard starting issues. The 4.2's fuel filter has a return line this should be on top. Above the port that goes to your carb. Also the whole filter should should be mounted above the fuel inlet on the carb. That is why the 4.2 has those hard fuel lines.

If either if these are not right, fuel from the float bowl could be returning down the return line. Then when you go to start the engine you have to fill the float bowl which you can only do by cranking the engine since it's a mechanical pump. Hence the long cranking after it sits.
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Old 12-10-2014, 07:44 PM   #8
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I have no issues with mine I started it for the first time in a week. Pump the gas 1 time and she fires right up.

(Weber 38 carb/ Crt Hei ) I also have a engine block heater I plug in. And it's garage kept

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