Re Will not start

[chiz]

OK
There seems to be a gas cap mod that allows better atmosphere pressure air into the tank, anyone hear of this? How would one add a pump; in line or in tank? Would a later tank with pump in suit fit an 84 or am I wrong in assuming the later models had pumps in the tanks. 

[Pat Conlon]

In the US the '89 and later FJs have fuel pumps, not in the tank, but external under the right side cover.
'84 to '87 FJs are gravity flow.

Adding a fuel pump is not your answer, your FJ should run fine with your stock set up.
You need to get it running first, then worry about modifications.
If you think it's your gas cap, just open it up and see if it helps.

Report back.

[chiz]

Dont know how to do this, It will start and run fine sometimes....Then when I put back on the tank switching over from the lawn mower tank it will not start.Then I take the tank back off to remove the in line filter and rout the gas line better put everything back ..it wont start  let it sit in a hot shed for a day and it will start, and will start every day for a week fine and dandy. But because I cant figure out why it has a mind of its own I don't ride it ANYWHERE.This bike is new to me but started fine with the previous owner.
Truly believe it is a fuel tap fuel line gravity feed issue will tackle the issue again pls feel free to ad your suggestions. Lez   

[Arnie]

Your lawn mower tank is much higher than the FJ tank when fitted, so has more "head" pressure delivering the fuel. 
Your tank and/or the fuel line may have crud in it restricting the flow. 
Clean the tank, and replace the fuel line making certain you route it correctly.
Check and clean the petcock filter if you have one. You'll have to remove the petcock from the tank to do this.
Check and adjust the carb float heights. they may be restricting fuel flow.
By all means, do a 'flapectomy' in the cap if you haven't already.

Hope that helps,
Arnie

BTW  Where are you?  Someone here may be close and willing/able to help you.

[movenon]

Your lawn mower tank is much higher than the FJ tank when fitted, so has more "head" pressure delivering the fuel.  
Your tank and/or the fuel line may have crud in it restricting the flow.  
Clean the tank, and replace the fuel line making certain you route it correctly.
Check and clean the petcock filter if you have one. You'll have to remove the petcock from the tank to do this.
Check and adjust the carb float heights. they may be restricting fuel flow.
By all means, do a 'flapectomy' in the cap if you haven't already.

Hope that helps,
Arnie

BTW  Where are you?  Someone here may be close and willing/able to help you.

+ 1  

It is just a fuel feed problem. You seem to have it isolated. Start at the tank and inspect everything..... Do what Arnie is saying.  When everything is in spec. they run just fine. You just have a restricted fuel flow. Its not a factory design error, something is plugged, broke, not installed properly or pinched.  Make sure you don't have a fuel filter or anything not stock in your fuel feed system. And please pay attention to the correct fuel line routing and that the tank when installed is not pinching your fuel or vacuum line.

Also read through this thread and look a the pictures it might also help http://www.fjowners.com/index.php?topic=9266.0

You also seem to have two different post relating to the same problem. Gets confusing.

Hang in there my friend.
George