78 FJ 40 wont idle

MudBoy2 · 07-27-2009, 01:38 PM

Hi all,

I have a 78 FJ 40 that has been running ok for about a year as my daily driver but has been having some trouble the last few days. I have noticed that it was running pretty rich (i think) the last month or so since the mileage has dropped to about 7 mpg and it backfires when you get off the accelerator, but now it will not idle for more than a few seconds. I can start it right up and make it run by feeding it gas but if I stop it will die. There seems to be no difference with hot or cold motor and I put some fresh fuel in the rear tank and that did not help either. Any thoughts? Electric systems seems to be running strong and it does not feel like a "miss." Removing the air filter does not help so I don't think that it is suffocating. The carb was replaced at one time with a Rochester Carb which I can't seem to find parts for any more.

My feeling is that it is carb related but I am also open to other thoughts and suggestions. If you were going to replace the carb what would you use? Weber any good?

Any how, thanks for any help.

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NicCantDecide · 07-27-2009, 02:51 PM

I'd say get the carb tuned before you start replacing parts. If you don't know how to do it yourself, see if a friend does or find a shop nearby.

MudBoy2 · 07-27-2009, 03:48 PM

I've done some carb work before but mostly on motorcycles. I had thought of pulling it off and cleaning it to make sure that the jets were clear and that everything was functional but other than that I'm not very familiar with them. If I have looked correctly, Rochester Carbs is no longer in business so parts or replacement jets could be hard to find. That is why I was leaning toward replacement.

FlyingLow · 07-28-2009, 08:57 AM

I don't know much about Rochester carbs. I say put a propperly tuned Asin carb back on it. Some poeple like them but I don't think Webbers are the way to go on these engines.

MudBoy2 · 07-28-2009, 09:28 AM

Thanks for the tip. Where would you look for an Asian carb?

FlyingLow · 07-28-2009, 12:26 PM

Quote:

Originally Posted by MudBoy2

Thanks for the tip. Where would you look for an Asian carb?

I would look in my garage but if I were you I'd look in the for sale section of ih8mud.com. I know I have one off a 78 but cross boarder shipping is a pain. Let me know if you can't find anything more local and we will see what we can work out. (I'm assuming your in the US?)

Don't jump on the "change my carb right now bandwagon" too quickly, you might be able to clean out the idle circuit in the rochester and get it going again but long term I'd be wanting to change back to Asian. The pickup for the idle circuit will likely be in the bottom of the float bowl so I'd start looking there just to get back up and running again.

MudBoy2 · 07-28-2009, 01:16 PM

Thanks again. I'll try cleaning it out as soon as I get a little time.

07-28-2009, 08:57 AM	#4 (permalink)
FlyingLow Registered User Join Date: Jul 2007 Location: Van Island BC Posts: 93	I don't know much about Rochester carbs. I say put a propperly tuned Asin carb back on it. Some poeple like them but I don't think Webbers are the way to go on these engines. __________________ 77 FJ40 36 TSLs, 45 springs in rear, 8274, ARB rear, TBI 2F 97 4 Runner Ltd TLCA# 9203

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07-27-2009, 02:51 PM	#2 (permalink)
NicCantDecide Registered User Join Date: Apr 2008 Location: Tempe, AZ Posts: 330	I'd say get the carb tuned before you start replacing parts. If you don't know how to do it yourself, see if a friend does or find a shop nearby.

07-27-2009, 03:48 PM	#3 (permalink)
MudBoy2 Registered User Join Date: Mar 2008 Posts: 8	I've done some carb work before but mostly on motorcycles. I had thought of pulling it off and cleaning it to make sure that the jets were clear and that everything was functional but other than that I'm not very familiar with them. If I have looked correctly, Rochester Carbs is no longer in business so parts or replacement jets could be hard to find. That is why I was leaning toward replacement.

07-28-2009, 09:28 AM	#5 (permalink)
MudBoy2 Registered User Join Date: Mar 2008 Posts: 8	Thanks for the tip. Where would you look for an Asian carb?

07-28-2009, 01:16 PM	#7 (permalink)
MudBoy2 Registered User Join Date: Mar 2008 Posts: 8	Thanks again. I'll try cleaning it out as soon as I get a little time.