1987 NQ50 not cooperating

[UltraFJ40]

Hi all, I guess I have finally caved and decided to seek help directly from the braintrust here. I have been browsing this board for the past few years and have found a ton of great info. This time around however, I am completely dumbfounded as to why my 1987 Spree will not cooperate. Currently it has 682 miles on it, so it sat and sat for a while before I bought it five years ago.

The bike ran fine for a few years, then died on my way home about a mile away. Never could get it started again and then got busy so it sat for a while, like a year or so. Recently I cleaned the carb, gas tank (had some rust), replaced the spark plug, bought a new air filter and oiled it properly. Well, after reattaching the carb, the scoot wouldn't run. It would start, then idle for a minute and then die. I cleaned it again and again. It would start and idle but die under any throttle with or without load on the bike.

I ordered a new OEMSTD carb from Wincycle on eBay. I figured I'd throw that one on while I took my time and rebuilt the original. It started,went fine for a short drive of about 1/4 mile then shut down. It would not restart again until about an hour later.

My obsevations:
-I've checked that the plug is getting fuel, although it seems not to be very much.
-I've adjusted the fuel/air screw 47 ways to * and back again.
-It also seems to sound like it has a bit of piston slap (I don't even know if this is possible).
-I have noticed that the plug gathers quite a bit of black on it (oil).
-I also noticed that the carb from eBay has an additional port near the fuel inlet. I don't know what it is so I plugged it, an unplugged it, and plugged it...

When it does start and idle, either it dies on it's own after a few minutes or it will die when I give it throttle, even lightly.

Could any of you offer me some advice as to which direction to go? I would really appreciate it. Right now I'm very near to taking a "BFH" to it.

Thank you in advance and yes, I have used the search function.

[UltraFJ40]

I did remove the plug and hold it against the frame. It has a pretty good arc, although it isn't quite blue, it appears light orange but I did it during the daytime with my garage door open.

[motormike]

First: that extra tube on the new carburetor is likely just an atmosphere vent. Stick a hose on it.
Second: when a scooter engine will idle, but won't throttle, it is almost certainly not getting enough fuel through main jet.
Third: if the fuel is sufficient, and still won't throttle, start searching for air leaks.
Fourth: if possible, get a compression reading. This will help in deciding the worthiness of the cylinder/piston rings.

[UltraFJ40]

Thank you Mike. I will begin in the order that you have written.

I do appreciate your help as I'm pretty frustrated with it at this point. I have a thing for older Honda and Toyota's and this thing is the only one that's ever had me this aggravated.

I will update as quick as I can.

[kennedy759]

when my 85 spree was doing that, the tube from the air filter box was not secured to the carb. ended up using a worm gear type hose clamp on it.

[UltraFJ40]

Thanks Kennedy, although it is on there and on there tightly, it IS only secured with a zip tie.

That might help me to hunt down the Gremlin.

[patthesoundguy]

I would go back to the original carb. I wouldn't want to introduce another wild card in to the mix. Start from the top and work your way down from the tank to them carb. Fresh fuel and is the tank screen clear. Apply some vacuum to the vacuum line for the fuel petcock with the fuel line removed from the carb to see if you get good fuel flow to the carb. Check the carb one more time and ensure the small orifice in the float bowl that feeds the pilot circuit is clear and light shines through. Try a new plug and gap it to 0.025" checking the spark with a spark tester might be a good idea. Check the air filter again. Check the airbox lid make sure it has the foam rubber gasket. As someone posted check the air hose from the airbox to the carb make sure its attached and use a new hose clamp. Set the idle air screw according to the manual spec to start. Making sure there is good oil flow from on the oil tank may be a good plan also along with a compression test.

[UltraFJ40]

I did go back to the original carb but...

When I went to start it, it refused to play along. Knowing that it only needs spark, air, fuel and compression I started to mess with the variables.

I removed the vacuum line that runs from the petcock. With this line removed, the thing runs and starts fine through all of the rpm ranges. I'm thinking that maybe it's a faulty petcock valve. If I leave it disconnected, it starts and runs just fine.

Will having the vacuum removed affect the oil pump? I believe it also runs with a vacuum, no?

Thanks in advance for any thoughts that you might give me other than to buy a new petcock and fuel strainer?

[patthesoundguy]

The oil pump delivers oil to the intake. Now you need to remove the vacuum line and the fuel line and see if you get fuel flow from fuel line when you apply vacuum to the vac line. Now if you remove the fuel line from the carb with the motor not running and fuel flows freely other than what's left in the line you know the petcock is toast. Its kind of okay of the petcock allows fuel to flow to the carb with no vacuum but not OK for the petcock to all fuel to the intake through the vacuum line. If you remove the vacuum line from the intake you must cap the hose barb on the intake and possibly the vacuum input on the petcock as well. If the screen on the petcock is clean and fine just buy an inline vacuum petcock for about 3$ on line and be done with it. When you remove fuel flow from the carb remember that there is a min or so worth of fuel in the carb so just pulling the vacuum line is not enough to show a faulty petcock.

[UltraFJ40]

Thanks Pat,

The vacuum hose barb on the intake is still uncapped. When I place my finger over it, the scoot dies. The same thing occurs when I go to put the vacuum line back on the barb, only it does not die it bogs as if it's going to die.

The petcock does allow fuel to flow when both are disconnected and I put vacuum to it but does not allow fuel to flow through the vacuum line, just the fuel line.

Thank you again for your insight. I really wish Honda would have kept making the Spree much in the same way I wished Kawasaki kept the two stroke Ultra 150 Jetski or Toyota kept the FJ40.

Well, a fella can dream can't he?



*I'll keep the thread updated but I don't think I'll be breaking any new ground. Mostly I'd like to help someone else that might be trying to revive one of these.

[UltraFJ40]

I've done everything suggested except replace the in tank filter. I ordered a new petcock and a filter from South Sound (HondaBikes.com) but still haven't rec'd it yet. If and when I get it, I'll update the thread.

Thanks again to everyone who chimed in. It is much appreciated.

Cheers!

[motormike]

The engine should run with the vacuum barb capped.
It concerns me that yours dies with that barb capped.
Seems to suggest that the filter or airbox is not flowing air very well.
Did you check compression?
Always start the tuning process with the idle mixture screw 1 1/2 turns open from full stop.
That way, your not chasing a phanthom.

[Wheelman-111]

Greetings:

The engine needs air + fuel in the right range of proportiins to run... apparently yours is getting all of its idle air from the vacuum port . This suggests that your throttle slide is closing too much. Cap that port and check that throttle stop screw. Turn in until it idles, then adjust the idle Mixture screw.

[UltraFJ40]

You guys hit the nail on the head. I finally rec'd my petcock and in tank filter. I installed them, switched over to clear fuel lines to be sure. I fired it up, idled great and even proceeded just fine under load but WOT it would die.

Then I moved on to adjusting the throttle stop screw inward (preventing the slide from fully seating). Fired it up and took it for a spin. It idles and runs very well under full load and at WOT.

Just like an old Honda should.

I think I burnt a low beam filament along the way because I have no low beam. Hi is just fine but no low. I think I'll just order a new headlight, throw it in and be done.

Thank you guys for all of your comments, the throttle slide wouldn't have entered my mind had you not mentioned it.

Doug

Oh yeah, for what it's worth I was able to locate a gas station that sells non-ethanol/recreational fuel. That's what she'll be using from here on out.

[patthesoundguy]

Make sure to test the bulb with a meter for continuity before ordering a new one. Or just swap the hi beam lead to the low beam lead of the light and see if both are good with a known working wire.