My 86 won't idle for long, please help.

GuitarJones · Post by **GuitarJones** » Thu Apr 28, 2005 12:27 pm

First thanks in advance for helping a newbie out. I've already searched here and other forums but haven't come up with an answer. Here is the problem.

Starts OK, choke works and idles up, runs OK also but sputters just a bit, like a sag on acceleration. What it won't do is idle down for very long. To keep it running I have to turn the idle speed screw in and then it's too high. I turn it down and it will idle for 10 to 30 seconds and then die. Starts right back up with a little throttle and starts the process all over again.

Here is what I've found and what I've done.

Fuel tank was rusty, cleaned and coated tank, all is well there.
Removed the tank inlet screen.
Cleaned the shut off valve and it is working properly.
Cleaned the carb and it is fine.
Adjusted carb as per instructions.
Eliminated fuel filter temporarily to discount as part of problem.
Checked for air leaks.
Replaced spark plug.
Cleaned air filter.
Checked all the electrical connections.

I might add at this point that I don't have a battery in it yet, should that make a difference?

The scooter ran fine before it was stored away for 3 years. Oh yes the oil injector is working properly as well.

Thanks again for any help you can provide,
Jones

mikehailwood · Post by **mikehailwood** » Thu Apr 28, 2005 4:35 pm

After you cleaned the carb could you see light through the idle jet before reassembly?

GuitarJones · Post by **GuitarJones** » Thu Apr 28, 2005 6:21 pm

I didn't try to see any light through it, I blew compressed air through it though. I'll take it back off and check, thanks.

hondaman · Post by **hondaman** » Thu Apr 28, 2005 9:53 pm

Try setting your throttle jet needle valve to a different
notch setting. The top notch will give you a leaner setting.
The middle notch is the standard setting.
The bottom notch will give you a richer setting.
Try it . If it doesn't make a difference or if the engine runs poorer
just go back to your original notch setting.

GuitarJones · Post by **GuitarJones** » Fri Apr 29, 2005 1:29 am

Thanks, I'll play with it some more later today. I've got to get some parts for my piece of crap Linhai too.

mikehailwood · Post by **mikehailwood** » Fri Apr 29, 2005 8:55 am

The only way I have been able to test and see that my idle jet is clear is to use a small (like a mini-mag) flashlight. I put the flashlight lense against the top of the carb (where the cable enters) and hold my thumb over the main jet orifice (so I am not distracted by light coming through there). Then I have to move the carb a bit until I find just the right angle to view down the pick-up tube into the idle jet. If I see light I know I'm good to go and if I see no light I know it's still blocked. I do this in a completely dark room. (insert wisecrack here)

ferchja · Post by **ferchja** » Fri Apr 29, 2005 9:09 am

Based on your above problem/procedures it seems that you plugged the jet or the intake for the float needle. When you have that must rust in the tank to warrant a cleaning, the little pieces cause havoc all over in the carb.

The above is a good start, anytime you have a idle that just fades after x number of minutes/seconds, the first suspect is always fuel flow. Start with the petcock and work your may to the carb. You will need a vacuum tester/pump to test the activation of the fuel valve diaphram and the idle valve ($20 at a Autozone). Great tool to have for carb work and brake bleeding for a car.

BTW someone mentioned testing the float needle by blowing in the inlet. Great advise! To add, the better way to test that the float is working is blow with the carb in its normal position (float hanging down). Should get air flow. Then turn the carb upside down, and blow in the inlet, and let the weight of the float close the needle. If you cannot blow air through with just a little pressure then you know the float is good.

Jeremy

GuitarJones · Post by **GuitarJones** » Fri Apr 29, 2005 12:15 pm

Went back through the carb with a fine tooth comb and some pin drills just for assurance. Everything is clean and it still does the same thing.

Is it possible that the shut off valve is weak and not functioning at low rpm's? Or maybe I'm just trying to get it to idle too low. I don't have a tach, haven't used one of them in at least 20 years.

mikehailwood · Post by **mikehailwood** » Fri Apr 29, 2005 2:25 pm

Shut off valve "strength" should have nothing to do with RPM's, only weather or not the float floats. If it leaks and takes on liquid, it will not float properly.
While off the bike, did you check that the valve worked by blowing air into it in both the open and closed positions?
While off the bike, did you check to confirm visually that the idle jet was clear?

ferchja · Post by **ferchja** » Fri Apr 29, 2005 5:41 pm

Were the pin drills mic'd? Could you take a reading of the diameter of the fuel inlet jet? It may be clogged, but not blocked.

Before messing with the carb anymore, I would still check the fuel valve, the diaphram may be stuck at a nearly closed position feeding just enough fuel to the bowl to let it idle, but not enough to maintain idle. Have you tested the choke? It may be keeping the carb at a cold start choke position and not allowing the engine to breathe after it warms up.

With it sitting for 3 years, and the rubber diaphram sitting in a closed position for those 3 years, it seems it would be the logical choice. Jets do not clog from sitting, assuming you properly drained the bowl prior to storage.

I have worked on a few 2-cycle engines that the diphram gets a varnish glob of crap under it keeping it locked in whatever position it was. (these were all stored somewhat properly for 2-5 years)

My $0.02.

Jeremy

GuitarJones · Post by **GuitarJones** » Sat Apr 30, 2005 12:56 pm

Remember this thing will run down the road about 37 mph. So I don't think fuel delivery is a problem.

I didn't try to size any holes just make sure they were clear.

Here's an update I did today. Put a new battery in and it turns over great, doesn't start though. It will start if I kick it though, what's up with that?

I took the carb back off and moved my main jet needle one step richer, there are 5 notches on this one. I went back over the carb including one hole, I assume to be the idle air bleed, maybe not, either way I overlooked it earlier. I ran a .015 wire gauge through it, checked my needle and seat again and reassembled. It has now idled for over two minutes so I'm happy with that.

I am not happy that it doesn't start with the starter though. Turns over great, but won't fire off. Kick start it and starts right up. Now I'm getting frustrated.

Thanks for all the help so far from everybody, I really appreciate it.

Jones

vette76 · Post by **vette76** » Sat Apr 30, 2005 3:01 pm

37 mph? thats good for a spree.

GuitarJones · Post by **GuitarJones** » Sat Apr 30, 2005 6:53 pm

Well yeah, that's crouched down and flat out for about an 1/8th mile but it will do it. 35 isn't a problem even with my 190 pounds on it.

hondaman · Post by **hondaman** » Sat Apr 30, 2005 7:13 pm

I have just the opposite on my 86. I removed the entire kickstart because the gear that the kickstart pedal goes on was shot. Mine starts good with the electric start.
You say the engine cranks over good with the electric start but the engine won't fire?
But it starts right up with the manual kickstart?
Thats a new one for me.

vette76 · Post by **vette76** » Sat Apr 30, 2005 7:40 pm

yeah, that happens to me sometimes too.re-charge the batt and i bet it will start. it seems like its turning over good but is really too slow.