Last time I drove it, it drove like crap, would only start if I pumped the throttle. And needed the choke on half to NOT die. So I decided to start it recently, and the airbox was filled with gas. So I decided to install a kit and clean the carb. Got it done, changed the oil, and it still wouldn't start. Swapped carbs with my other bike, which runs fine, and this bike still will not start. Engine turns and there's spark, but it rarely even tries--then there is backfire with no starting. But mostly just turns and no trying to start. I plan on checking the valve lash, but I adjusted the intake valve not long ago (I've never done the exhaust). I just thought I'd chase the most obvious, since the original problem was likely the carb gunked up. Could the carb problem have damaged the engine in some way? Any other ideas?

 

Suzukis often do this if you leave the tap on prime, and they can be quite hard to re-start, probably because fuel gets everywhere, and the mixture will be rich until it all gets used. My way is to open the throttle wide, no choke, and churn away until it fires up. Try without the airbox connected, most of the excess comes from there, even after you have cleaned it out. A nice dry plug helps too. I guess a "hydraulic lock" could have done some damage. This would need checking with a compression test.

 

Thanks, merryman. We did try cranking it many times without the air box on. Then tried a little starting spray (ether?). I even switched spark plugs with my other bike. My buddy says he has a compression tester for cars. Hope it'll fit in there.

 

You didn't mention what the plug looked like when you pulled it...was it soaking wet, little wet or bone dry? I know you changed the plug, but did you test for good spark? If you put your thumb over the plug hole & crank does it blow it off? We need to first determine if you're getting fuel (wet plug), have good spark (blue spark when grounded to frame and some level of compression (thumb thing is just to prove you don't have stuck rings or a whole in the piston). If all of these are present, then ignition, valves or timing could be next to check...


If you have the basic three (and not other issues), starting fluid should fire it right up...

 

If there is a boot between the air cleaner and carb, check for cracks. If the pilot jet is clean, float height set and the pms screw is set 1.5-2 turns out and the choke is working, check that the diaphram on the air slide/piston is properly seated, should be good to go. If the floats are set wrong, gas will overflow, or if you don't shut off the fuel when trailering, it can overflow. It's not just a Suzuki, thing, any carb can do the same, if it's bouncing down the highway on a trailer, gas can go straight into the cylinder. I have a 500 Suzuki in my Arctic Cat, once the carb was finally tuned, it runs like a Swiss watch.

 

Thanks, DirtDevil,
Plug was pretty dry. I didn't try the thumb thing, but before I realized there was a gas flood, I tried cranking it several times, and it was like the starter was jammed or something. Of course, it couldn't turn because there was so much gas in the engine. Took plug out, and it turned great. Blue spark was there using a nail to check the plug. I'll try the thumb thing tomorrow if I get time.

 

Hondas have a drain pipe so, if the carb floods fuel dribbles out onto the ground. Suzukis don't, if they flood, fuel goes into the airbox and engine. Not sure about Yams, most have the same carbs as Suzukis, but Yams don't have the vacuum operated fuel tap, so I would have thought a Honda style drain pipe would be needed in case they flood. If there is, yours must be blocked. I am not an enthusiast for starter fluid, unless the problem is a shortage of fuel, it won't help an engine to start, and dries the cylinder walls which will already be short of oil from the wash of fuel they got when the carb flooded.

 

When you turned the engine over with the plug out did gas shoot out? if crankcase was full of fuel it should have...


Merryman - starting fluid with cylinder protection is widely available and I use it often...especially on my sleds that have sat for awhile...they are not a gravity fed system so pulling rope 50 times to get the bowls full isn't fun...

 

DirDevil, thanks. I really don't remember much gas shooting out. There could have been some. Oil was definitely full of gas.

 

Ah yes...was thinking 2-stroke...sorry! Well...you're definitely getting fuel, you say you have spark...I'm down to compression and timing...I wouldn't think the valves out a bit would keep it from starting...unless one is bent and stuck open/close.


How quickly did the engine flood with fuel? The leak-down past those rings should be pretty slow...