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1998 KQ won't start - head scratcher


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Hi all,

I picked up this quad after the previous owner couldn't get it going.

The issue is that I can't get it to fire at idle or at all.

I've...

- replaced plug. Decent blue spark. Also tested with spark tester inline.
- rebuilt the carb. PO had already bypassed vacuum lines from petcock. There's fuel at the cylinder
- Checked compression with new gauge. reads 190 psi
- cleaned all contacts I could access.
- am currently jumping with car battery. Solenoid jumpered.
- checked cam timing at TDC and adjusted valve lash
- put gas directly into cylinder to see if it will fire at least momentarily

Motor turns over well. Plug gets wet. 

Motor may fire once or twice but smokes through exhaust a bit as if it's trying to fire or combusting.

This leads me to suspect timing. As mentioned I checked the flywheel mark versus cam marks. Perhaps someone has been in there before because I can't find a 'T' on the flywheel but there is a very visible paint mark which aligns with TDC position on piston. Possibly a slipped flywheel/woodruff?

Is it possible that if it had seen previous repairs, that the timing could still be off? I'm reluctant to dig into the flywheel/stator area if there's something else I could have missed but all signs point me to that area. Would a bad CDI cause spark timing to be off?


Anywhere else to diagnose incorrect spark timing?


I've scoured these forums and elsewhere but I'm posting just in case there's something I've overlooked up until now.

Thanks very much for reading!


Warren

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Check your carb again. Your float might be off and overflowing the carb internally. Make sure the carb is in spec. If your getting spark and timing is in spec on the valves, then to much fuel will foul the plugs and prevent it from firing.

Sent from my SM-N920V using Tapatalk

Also there are timing marks on the stator side thru a plugged hole. You will need a screw driver to pull them off. Then take the hole center of the casing and put your socket in there. Turn the motor and align the timing at tdc. Then check your cams.

Sent from my SM-N920V using Tapatalk

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Thanks.

 

A few things...

 

Would it be possible to eliminate the carb as an issue by simply removing it and direct injecting gas into the intake and/or through the spark plug hole? Wouldn't it run a few seconds at least?

 

Trying to visualize the timing marks. I'll go check that now.

 

I appreciate the assistance!

 

Warren

 

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37 minutes ago, 06kfx440 said:


 

"Also there are timing marks on the stator side thru a plugged hole. You will need a screw driver to pull them off. Then take the hole center of the casing and put your socket in there. Turn the motor and align the timing at tdc. Then check your cams."
 

I think we're talking about the same thing. On mine, the flywheel mark plug is a 17mm head, though my 'mark' is obscured or highlighted by a white paint mark. It seems to gel with TDC compression and I've already done that.
 

 

Edited by Ed Zeppeli
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I would NOT remove the carb and try sending fuel into the engine.

 I know you tested spark but I would pull the plug out and rest it against the head. Turn the fuel off and crank the engine watching the spark for about 5 seconds and see if it’s consistent.  Make sure there is no difference in the rhythm of the spark while cranking. For instance, you see spark for a few cranks and it goes away and comes back is what I mean. It should be steady.

Then I would go back to the timing and triple check that’s its good. Find the T mark.

 Like @06kfx440 said go through the carburetor and make sure the float is good and all settings including the fuel air screw are set properly. The main jet needle setting “the E clip” what’s it set at ? 

Fuel pump, (if fuel injected) make sure its good and not pushing too much fuel into the engine. Make sure the boot that connects the carb to the engine is good and no cracks.  

Make sure your fuel is not bad. 

Is the choke working correctly and the air intake clear of any nests or obstructions? Been nests rodents etc. 

check your voltage at the battery when cranking. Could be a bad regulator. 

Go through these things and get back. Take your time and  make sure your good. 

 

 

 

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9 hours ago, Frank Angerano said:

 

 I know you tested spark but I would pull the plug out and rest it against the head. Turn the fuel off and crank the engine watching the spark for about 5 seconds and see if it’s consistent.  Make sure there is no difference in the rhythm of the spark while cranking. For instance, you see spark for a few cranks and it goes away and comes back is what I mean. It should be steady.

 

Ok. Will try that again and look for steady pulse at the plug.

 

Then I would go back to the timing and triple check that’s its good. Find the T mark.

 Like @06kfx440 said go through the carburetor and make sure the float is good and all settings including the fuel air screw are set properly. The main jet needle setting “the E clip” what’s it set at ? 

 

e-clip is at the fourth notch.

Fuel pump, (if fuel injected) make sure its good and not pushing too much fuel into the engine. Make sure the boot that connects the carb to the engine is good and no cracks.  

 

Boots look good. Not an EFI model but pump seems to pulse. Pet-cock vacuum activation has been by-passed by previous owners. I suppose it's a common mod? Vacuum line from petcock is plugged with a screw as is the carb side.

 

Make sure your fuel is not bad. 

Is the choke working correctly and the air intake clear of any nests or obstructions? Been nests rodents etc. 

 

Fuel should be good. Choke plunger moves freely in its location and cable has been lubed.

 

check your voltage at the battery when cranking. Could be a bad regulator. 

 

Will do.

Go through these things and get back. Take your time and  make sure your good. 

 

 

Thanks for the feedback. Though I had gone through the carb and cleaned it all out I ordered a kit anyway and it arrived yesterday. I've installed it and am ready to test again today. Also, yesterday I went out and got a proper atv battery and starter solenoid for it. Up until then, I had the solenoid jumpered and was using a car battery to get the starter spinning. I didn't feel good about it as there would be no battery when it finally got running and the manual says that's a no-no.

 

9 hours ago, Frank Angerano said:

 

 

 

 

 

Will report back with my findings today.

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5 hours ago, 06kfx440 said:

Your high idle may be an intake boot or a disconnected filter or a vaccume leak somewhere.

Sent from my SM-N920V using Tapatalk
 

 

Heh. Yeah. I was about to go digging around for that kind of trouble.

 

Turned out to be a kink of some sort in the throttle cable. I had cycled it fully before twisting the carb into position and it all looked good.

 

Go figure.

 

I'm just glad I didn't have to take the carb out again.

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