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View Full Version : Mitsubishi Mighty Max 1988 2.6 has trouble starting cold



BJH324JH
05-15-2016, 04:22 PM
Hello, I am new here and have loads of questions to ask. I am happy to be part of the community and hope to contribute to the forum in some way. Now to my question, I have a Mitsubishi Mighty Max 1988 2.6 and I am trying to troubleshoot why my truck has trouble starting up when cold. I have to step on the gas to help it turn on. After a few presses of the gas pedal, the truck starts and idles great. I'm no mechanic, but having to press on the pedal to help the truck start doesn't seem right. Is there something that I can do? I also replaced the old carb with a brand new one and had it installed and tuned at a local carb shop. Although I did forget to give them the new gaskets that came with the new carb. So the old ones are still there. I was wondering if I can replace them myself and not have take it to the carb shop to have it readjusted? Any help is well appreciated.

pennyman1
05-15-2016, 04:34 PM
A carbureted motor requires you to push the gas pedal to the floor once or twice to set the choke and prime the motor to start. Only fuel injected vehicles start without pumping the gas. You should be able to change the gaskets without having the carb shop do it if you have some mechanical skills. If that is your only issue with the factory carb, you are lucky. Welcome to the forum - we need pics!

BJH324JH
05-15-2016, 04:55 PM
That's interesting, I didn't know that. Although, I do have to pump the gas pedal more than two times to start the truck up. Here is some sound of me starting the truck up. If that helps at all? :shrug: http://s000.tinyupload.com/index.php?file_id=58871565075563099426

pennyman1
05-15-2016, 04:59 PM
If it takes more than 2 pumps to the floor to start, the choke isn't setup right. Go to our manuals section for the instructions on how to set the choke so it works. You should also change the fuel filter - it is back by the tank since you installed a new carb.

BJH324JH
05-15-2016, 05:23 PM
Here are some pics of the carb gaskets that were supposed to be put on the first time the new carb was installed!:

http://s32.postimg.org/xsqyf1tas/Gaskets.jpg (http://s32.postimg.org/xsqyf1tas/Gaskets.jpg)

Just to make myself clear, as I think there is confusion. The truck does start when I pump the gas pedal one to two times, although it doesn't stay on when cold. I have to keep pumping the gas pedal until the truck warms up quite a bit. In other words it won't idle cold until I keep pumping the gas pedal till it gets warm enough to idle by itself. If you listen to the file I linked you can hear me initially just turning on the truck without pumping the pedal. It won't start as you said, "A carbureted motor requires you to push the gas pedal to the floor once or twice to set the choke and prime the motor to start." Okay, so I do that, I pump the gas pedal about two times and it starts, the problem is it won't idle cold. I have to keep pumping the gas pedal until it warms up a bit for it to idle by itself. Is this normal?

geezer101
05-15-2016, 08:48 PM
The gaskets in question are 'supposed' to be put on or 'are' installed? If the original gaskets are fouled or have tears it will be an issue straight up. If the auto choke butterfly is in a near completely closed position on start up then I'm gonna say there's a vac leak in it somewhere. Other option is the air/fuel mixture screw is set incorrectly. Make sure the mounting bolts are on firmly and give the base of the carb a liberal squirt of WD to see if the idle fluctuates. Check other places where a leak can take place - brake booster line, all the small vacuum hoses and check the inlet manifold nuts to see if they're tightened sufficiently. Vac leaks can be a bane to hunt down. If all is good then 2 pumps of the pedal and throwing the key over should be all it takes to start the engine.

camoit
05-16-2016, 11:22 AM
Sounds like the choke spring is broke or off the linkage

BJH324JH
05-18-2016, 11:58 PM
The gaskets in question are 'supposed' to be put on or 'are' installed? If the original gaskets are fouled or have tears it will be an issue straight up. If the auto choke butterfly is in a near completely closed position on start up then I'm gonna say there's a vac leak in it somewhere. Other option is the air/fuel mixture screw is set incorrectly. Make sure the mounting bolts are on firmly and give the base of the carb a liberal squirt of WD to see if the idle fluctuates. Check other places where a leak can take place - brake booster line, all the small vacuum hoses and check the inlet manifold nuts to see if they're tightened sufficiently. Vac leaks can be a bane to hunt down. If all is good then 2 pumps of the pedal and throwing the key over should be all it takes to start the engine.

I just installed the new gasket a few days ago. Although the carb came with two gaskets as show in the picture I posted above. I hope I wasn't supposed to install two gaskets. I really do hope the other gasket was extra. Anybody know If I was supposed to install two gaskets on the carb mount?

BJH324JH
05-18-2016, 11:59 PM
Sounds like the choke spring is broke or off the linkage

Does the choke spring control the idle when you start it up?

geezer101
05-19-2016, 02:59 AM
I just installed the new gasket a few days ago. Although the carb came with two gaskets as show in the picture I posted above. I hope I wasn't supposed to install two gaskets. I really do hope the other gasket was extra. Anybody know If I was supposed to install two gaskets on the carb mount?

Only one gasket for the carb base. The 2 that you have been given look identical anyway - normally there's one with some overhang for the integrated EGR valve off one side.

BJH324JH
05-19-2016, 10:25 PM
Only one gasket for the carb base. The 2 that you have been given look identical anyway - normally there's one with some overhang for the integrated EGR valve off one side.

Thanks.