wont stay running

[mobleydrew]

Carb rebuilt, Pilot screw 2.5 turns out, new choke starter (choke) plunger and spring. Starts fine, idles too high, blip throttle idles higher but soon lowers to almost stalling. Turn idle screw up revs up, blip throttle, idles down again and stalls. I keep adjusting idle, keeps stalling after it revs real high.
I have also confirmed that the vacuum actuated petcock is functioning properly, yet, there was a puddle of gasoline in the airbox
Could float need adjusting since it is allowing carb to overfill? maybe a new needle valve?

[mobleydrew]

Writing things down sure does help a person self-diagnose. According to the manual, and my particular carb, there is no set "turns-out" for the pilot screw. It just says PRE-SET. P.O. had fooled with it previous to me (cap was already gone), and I can guarantee it was more than 2.5 turns out when I removed it for cleaning. I am thinking now that even 2.5 turns out is still too much. (I was looking at wrong carb spec chart). It is a 13F3 carb.
Whatcha think? Should I try 1.5 turns? 1.75, 2? Even the 13F2 carb is 1.375 turns out.
That may fix the odd idle. Will it fix the overflow of gas into the airbox some how, since the engine will suck in fuel at a slower rate now, at idle?
Thanks for reading.
-Drew

[spldart]

I could be totally wrong here but your idle circuit being off isn't capable of throwing an overflow of gas in the airbox.
Your description of the engine running screams big time air leak or as you have already surmised an overflowing bowl... or both.

Well... gas in the airbox... I'd check not only the condition of the needle and seat but the float level.

The fuel needle and seat are probably not worn out. It takes a long time to do that. so...
Clean any debris and make sure float is set properly. Are you super high miles?

My pilot screw was about 3 turns out plus or minus. Pilot fuel circuit didn't seem to overly sensitive to me. This is one of the most f/a ratio stable carbs I've dinked with so with these problems look for an air leak, flooding or other more severe issues.

[spldart]

New choke plunger and spring.
Is it fully engaging/disengaging?

[mobleydrew]

I have it idling better, at 1.5 turns out, but think 1.5 is starving for air. It eventually stalls. Choke is functioning properly and adjusted float slightly. The gas in the air box, it seems, had been in there for sometime....before I bought it a few weeks ago. Gas was already turning brown, as it does over time....or just discolored as a result of the black plastic air box.
Recommendations on turns out for air screw, since manual just says PRE-SET?
Just trial and error?

[blaine]

Start at 2 1/2 turns out.Than with bike idling warm adjust slowly for best smoothest idle. :) ;)

[Water Warrior 2]

The puddle in the air box is likely from gases and blowby from the crank case breather. This is a common no cost option on GZs and most other engines. :lmao: Just kidding about the option part.

You can drain the excess from the air box using the hose that hangs down from the box to below the bottom of the frame. It will have a plug in the end of the hose. Pull out the plug, drain and replace the plug.

[mobleydrew]

1.5 turns out, can tell starving for air and stalls, 1.75 turns out, still starving for air but better, still stalling. 2.0 out, revs high then drops down slowly and stalls. 2.5 out, revs higher then drops down slowly and stalls. At the higher turns out, after stalling, difficulty restarting until engine cools. (running so lean that it overheats?)
Only way to maintain idle is at 3,000 RPMs (I have an RPM setting on my meter). I have sprayed engine starting fluid around carb to guarantee no air leaks. Choke plunger not binding.
Do I need to try to be so exact with turns out? Maybe 1.875 turns out?
It is the 13F3 carb, and air screw is not missing the spring, rubber o-ring or washer.
Ideas?

[mobleydrew]

Since there is such a big difference in how the bike runs, from 1.75 to 2 turns out, perhaps the small rubber o-ring on the air screw is worn, allowing air to flow through the air screw adjusting orifice. Perhaps a new o-ring and closing off the orifice will correct this. Once I confirm this with a piece of tape, perhaps a dab of gasket sealer will seal it nicely, since the original plug for the hole is long gone.

[mobleydrew]

SPLDART- Since 3 turns out worked for you, I think I will try going the other direction, since 2.5 turns and less are not doing it. At low idle, 2.5 turns out will only stay running with high idle speed, thus getting air through the main plunger. Dies if I leave alone at low idle, as thought not enough air getting through.
You have the 13F3 carb?

[blaine]

Like I stated adjust with the bike warm for smoothest fastest idle.No two bikes will have the same amount of turns. :)

[mobleydrew]

Ive tried 1.5, 1.75, 2.0 and 2.5 turns out. At the 2.5 turns out, as you recommended, on the pilot air screw on front underside of carb, it idles nicely for 20 seconds then stalls, like it is choking for air. (choke is not hanging up. New choke plunger and spring.) To stay running, bike must idle at about 3500. (Ive got a setting on my PDI Multi-meter that measures RPM). At 3500, the carb piston/plunger in the venturi is raised slightly, allowing the high speed jet to suck up the fuel, even though I am standing still.
I know it shouldnt be idling that high. Less than 1800 would be nice, and still stay running, although I am shooting for less than 1500. Still thinking it needs more air at idle speed.

Since someone else said 3 turns out (on the pilot air screw) worked for them, no hurt in trying.

Too bad the PO messed with the air screw at all, instead of leaving at factory specs. Bike isnt rejetted, stock air filter and pipe. No reason to have had to remove that little cap and adjust it. Should have known something was up with it since it was idling really high when I test rode it. Would have been great if the manual specified number of turns out instead of just PRE SET for my particular carb. That way I might know to look for something else.

Thanks for the continued advice, Blaine.

[blaine]

The pilot air screw does nothing above 1/3 throttle.If the bike is idling that high you have another problem that you need to address first.In order to adjust the PAS the bikes needs to be ideling at about 1200 RPM.Maybe a vacuum leak.You can spray WD-40 around boots to check for leaks.

[blaine]

I have reread the entire post & see that you checked for Vacuum leak around boots.It still screams of a vacuum leak/hose leaking.You can't use the pilot air screw to try & control the idle.It controls the mixture.That's why it gets adjusted with the bike idling warm. :)

[raul10141964]

Wat Cain of air filter is in it?

[spldart]

You see that little opening that the airbox allows air through to the filter?
Try and cover that with your fingers at varying degrees.
If idle climbs as you cover then it dies as you continue to choke it off then you have
air leaks. (lean)
If it just goes straight from barely wanting to idle to dead then your to rich. (overly
restricted is another possiblity)
That test doesn't work if you don't have the plug in the hose going down from the
airbox... Thus the (better test at the carb mouth comment below)

This test might be more accurate if you yank the airbox and place fingers over the
carb inlet itself.

When I used to mod to K&N filters I would test if I was still to lean by putting a cut
off sock end over the filter. If it ran better then I knew I still needed to jet up a bit.
The sock would slightly restrict airflow and a 'at throttle' lean situation would improve.

[mobleydrew]

It idles that high because I am forcing it too. I got to get it home somehow, when riding around in the neighborhood trouble shooting the performance. I turn the idle screw (not pilot screw) high to make it so. Youre right, the air screw does nothing above 1/3 throttle. Does little below too....which is my problem. Idles great for 20 seconds, then stalls. I restart and turn up idle ALOT in order to stay running so I dont have to keep blipping the throttle to keep it going.
Correct, idle screw is for adjusting mixture. Screwed in too far, not enough oxygen molecules to mix without fuel (rich). Too far out and too much oxygen will mix with fuel (lean). Since oxygen burns hotter then just fuel alone, it would idle high without touching the idle screw at all.
The problem is not the high idle, since I am forcing it to idle high. Problem is stalling at normal idle setting because it is NOT getting air. If I had air leaks, it would be idling high on its own without adjusting the idle. Spraying engine starter fluid all around intake boots, all over carb (both sides) and up the idle jet adjustment hole (to see if rubber o-ring is sealing properly) has no effect.
Could it be that the pilot adjusting screw is not the culprit, but the pilot jet itself is not allowing enough fuel through? Perhaps it is SOOO lean that engine is overheating, which explains why it wont restart until it cools off.

OE air filter, it looks brand new. Could the puddle of gas, that was found in the bottom of the air box, produced enough fumes to cause the air filter to deteriorate to a point where air no longer flows through it efficiently? (I think the PO left the PRI on overnight before I bought it, since the oil smelled like gas and was really thin when I changed it.)

[mobleydrew]

Maybe I should start over.....:D.
Hey guys! I start my bike. It runs and idles great for about 20 seconds then it cuts off. I try to restart it and it wont, regardless of using the choke or not. It just cranks and cranks without even a sputter. I will go out to bike after a few hours, starts, runs great, stalls, wont restart.
Why would it do this?
(keep in mind, I have rebuilt the carb. new choke plunger and spring)
Mentioned in previous thread. Since it starts fine after engine cools....perhaps it is running too lean, causing it to overheat, and I need to check the pilot jets themselves.

[spldart]

I may be wrong but it sounds like your float isn't set right.

Gas in airbox.
Once you start bike and the petcock gets vaccum to allow fuel flow you flood out....
Unless revving motor which keep the f/a mixture close enough to proper range to burn.

I dunno. Other stuff could cause this.

[raul10141964]

Inspect the spark plug , black =rich white=line


Sent from my HTC Desire 510 using Tapatalk

[spldart]

At this time I'd yank the boot from carb to airbox and start again. See if it idle dies and see if
you got a very wet carb interior when it does.
But that's just me.

And read your plug as previous post said ;)

[mobleydrew]

Gas in airbox.
Once you start bike and the petcock gets vaccum to allow fuel flow you flood out....
Unless revving motor which keep the f/a mixture close enough to proper range to burn.


No gas in airbox now. Only found once I got bike home from purchase. Only mentioned in case air filter is messed up as a result.

[mobleydrew]

Inspect the spark plug , black =rich white=line


PO replaced spark plug because it WAS only running with choke on all the time, so was fouled. I determined that the choke plunger was hanging up and not disengaging itself, which is why I replaced the plunger and spring. I checked plug last weekend. Looks good. slightly brown/tan. Not white and pitted as though running lean. Not black and oily as though running rich.

Ill try some of your suggestions tonight.

[mobleydrew]

I may be wrong but it sounds like your float isn't set right.

Gas in airbox.
Once you start bike and the petcock gets vaccum to allow fuel flow you flood out....
Unless revving motor which keep the f/a mixture close enough to proper range to burn.


Good hypothesis, I do smell a lot of gas, once the bike stalls out, like when a car floods. why would it flood? float set too high? no gas coming out of over flow hose on rear/right side of carb that is connected to float bowl.

[jonathan180iq]

Float could simply be stuck, never turning off fuel flow.

[spldart]

If you haven't already download the service manual. Link on this web site.

On page 110, according to my pdf reader, is the needle valve inspection.
On page 111 is the float adjustment procedure.

[mobleydrew]

When I was rebuilding the carb, I did notice something that was odd and may have been missing. Since it wasn’t there when I took the carb apart, I ASSUMED it wasn’t supposed to be there. See the picture attached and what the arrow is pointing to. Is that the 10mm piece that threads into the carb casting itself, or does this little thing sit inside that 10mm threaded part, and the needle valve (attached to the float)just sits inside it? Needle valve seat might be the correct term for it.
(picture taken from Partzilla. My SM illustrations are fuzzy)

[spldart]

Your needle seat is missing??
Did you see threads where something was suppossed to screw in that position?

When I was rebuilding the carb, I did notice something that was odd and may have been missing. Since it wasn’t there when I took the carb apart, I ASSUMED it wasn’t supposed to be there. See the picture attached and what the arrow is pointing to. Is that the 10mm piece that threads into the carb casting itself, or does this little thing sit inside that 10mm threaded part, and the needle valve (attached to the float)just sits inside it?

[mobleydrew]

Your needle seat is missing??
Did you see threads where something was suppossed to screw in that position?

Sounds like it.
The part that the valve needle seat is inserted into, the 10mm hollowed out bolt, for lack of a better term, is what the needle valve is currently resting in right now. Maybe it is the valve needle seat seat. Id send a pic of that if I had one. Sounds like I am missing something, huh?
Maybe the 13F3 carb is that different that the rest?

If this is what I am truely missing, then I must be flooding out. Wonder why the float bowl overflow is not allowing fuel to be spilling out onto the floor.

[blaine]

Sounds like it.
The part that the valve needle seat is inserted into, the 10mm hollowed out bolt, for lack of a better term, is what the needle valve is currently resting in right now. Maybe it is the valve needle seat seat. Id send a pic of that if I had one. Sounds like I am missing something, huh?
Maybe the 13F3 carb is that different that the rest?
Carb wouldn't be different in that regard.:)

[spldart]

If the opening the needle is in is threaded for a bolt then there is supposed to be a seat there. That carb cannot even come close to regular operation without the seat.
By the way. The seat is usually the same color as the jets and it looks like a great big
jet.
Without it you will always be flooding.

[mobleydrew]

Then I guess I will be playing in the garage tonight taking a closer look and placing an order for a new one soon.

Thanks everyone for the advice. Ill let you know what happens.

[mobleydrew]

Sorry. I was mixing up my mental images of Honda VF1000R carbs with this one. Wrenching on 2 bikes at once. The VF carbs have the big 10mm threaded holders that the valve needle seat fits into.

There IS a valve needle seat in the GZ carb.

I rebuilt carb again, spraying everything out again.

I confirmed the following are in the right places for my 13F3 carb; #120 main jet, #17.5 pilot jet, Pilot air jet 1 #87.5 and pilot air jet 2 #120.

#14 on diagram in SM (page 4-3) is the starter jet. It has a #52.5 in it. I did not see another #52.5 listed on the Carb Spec page (4-2) of SM. Is 52.5 correct?

I will check/adjust the float level, reinstall and start up again to see if anything has changed.

[mobleydrew]

Since the #120 main and the #52.5 starter jet will thread and fit into either place, i suppose I could have installed the #120 into the starter jet previously. Would this have caused it to flood?

[spldart]

iirc the two small pilot/idle circuit jets were rather dissimilar. One had a tube with
holes down the length. Jet orifice size was different too.
The service manual isn't specific enough?
I'd imagine that would cause some substantial issues switching them.. But!
I really wouldn't know as I haven't tried it.

[mobleydrew]

Yeah, the SM doesnt specify that the starter jet is a 52.5. it does specify the others though. the 17.5 has the little holes down the length, as well as the main.

[blaine]

Since the #120 main and the #52.5 starter jet will thread and fit into either place, i suppose I could have installed the #120 into the starter jet previously. Would this have caused it to flood?
Yes it would. :)

[mobleydrew]

Nope. No different. Even put in a new plug, since the orig was fouled by all of the fiddling.
Still will only remain running with idle turned up high.
I confirmed that it was sucking in air through air filter too.

Ichiban, from Ichiban Moto, is coming over this weekend to help me figure it out. He is local to me.

[mobleydrew]

The air passageways from Air Jet #1 (87.5) to Air Jet #2 (120) is clear. Thinking about it, carb floods, pours out towards air box. As it does, it gets sucked into Air jet #1 and out Air jet #2 which then gets sucked up into the top of the CV carb to the diaphragm.
Starter jet, with 57.5 jet removed. What is that thing in there and how do I remove it? Can I remove it? I want to make sure it is clean in there and not stopped up. (see picture).
I have adjusted float to spec. Still flooding. Perhaps I should adjust (lower) it some more.

[spldart]

I'm sorry. I'm drawing a complete blank at this point. Considering how clean looking the body of the carb appears to be... At this point if I were stuck I'd dunk the body of the carb in berryman chem dip then squirt it out with carb cleaner. Every orifice... I'm just not understanding why you'd have such problems with such a good carb :confused: :dunno:

[mobleydrew]

Had another recommendation from someone that said the valve adjustments could also be to blame. It made sense how he explained it. Gaps were indeed to small. Adjusted them and I also adjusted float more. Started right up on first push of the button. Idled better and lower this time before stalling, but still too high. Stuck my hand in air box and manifold was wet with gas again.
Perhaps the little rubber tip on the needle valve is worn out and not stopping the flow of fuel? Maybe PO used E15/E85 fuel? Maybe he used a carb cleaning solution that is not friendly to rubber parts? Petcock seems fine, and stops the flow of fuel when the engine is not running.
When I rebuilt the first time, I let it soak in one of those paint buckets of carb and parts cleaner for 24 hours, rinsed and sprayed out with Gumout.
I think I will order a new needle valve and needle valve seat, since it comes as a set, and see what happens. PO said the float itself was new, and it looks like it. Ill keep playing with it.
Thx

[mobleydrew]

It works!?!?!? Im thinking it was the needle valve seat AND/OR needle valve itself. The seat did insert tighter than the old. Im thinking the o-ring was worn out. Seems to no flood anymore. Adjusted idle down pretty far, put too nervous to adjust down close to 1300 just yet. Ill be more confident in the repaid over the next week or so, and only ride in the 'hood.
Thanks for you all of your help, Spldart!

[gzvirgin]

Had same problem. After much trial and error I realized the main jet and jet pilot (number 28 and 30 on the carburetor parts diagram) were interchanged. I put them in the right spot and bingo, perfection. Lots of gas in oil after experimenting though - make sure you change your oil.