Bogs or Hesitates Mid Throttle 2002 G-16

[CP241]

Originally Posted by mckittrick.joe

G2 runs good to high rpm in neutral. Bogs down in gear.would this still probably be carb?

Does playing with the choke make any difference?

[mckittrick.joe]

Originally Posted by CP241

Does playing with the choke make any difference?

Choke makes it worse

Sent from my LGL158VL using Tapatalk

[YamaKart]

Okay, I fixed the problem of hesitation.
1. Took the engine apart to get to the magneto. Electric wire brushed both magnet and coil. This took care of 80% of the problem. Maybe 90.
2. Tinkered with fine tuning the new carburetor
3. Set the valve gaps properly.

[CP241]

Thanks for the update. Glad you got it going!

[YamaKart]

Thanks for the input. It appears the problem might have been twofold. One, an 18 year old carburetor that many people had "fiddled" with. and Two, the timing involving the valve lash, you pointed out, and the magneto/coil being so filthy that the "reading"/timing was not clear. I am certainly keeping the Mikuni carburetor for a future rebuild if necessary. Thanks again.

[CP241]

I've seen some incredibly nasty pickup coils that worked perfectly fine... The one in my gator was so caked full of mud and muck the air gap between the 2 was completely filled with gunk. I had to dig just to find the coil But amazingly it still sparked like crazy, didn't miss a beat. The connecting rod, however, didn't fare as well........

Definitely save the Mikuni. A date with an ultrasonic cleaner full of carb cleaner will work wonders and make it as good as new!

[YamaKart]

CP241, after driving the cart a bit, it still has a bog (much better than before). You mentioned checking the new plug. I did and it's dry black carbon, which should indicate too much fuel. I've got the body removed so I dont have a choke cable to pull on to see if it runs better during "the bog". I can smell gas after I've run it a couple of minutes. This is starting to bug me. How about this. Since there was such a good improvement when I cleaned the TCI and magnet, could the 18 year old TCI unit be weak? There is a testing sequence, and proper resistance but I don't recall how or what it should be. I'm usually pretty good at repairing things, but this is getting my goad!

[CP241]

Resistance at the pickup coil should be around 400 ohms if I rememeber correctly. However, I truly do not believe this is your problem. If it was, it wouldn't run at all. The pickup coil only senses the revolution of the motor, which tells the ignitor when to fire, and then the ignitor tells the coil to fire.

I don't recall, what plug are you running? Perhaps stepping up to a bit hotter plug may help. Also, have you checked for spark with the plug removed? Should see a nice fat blue spark. I dislike the inline spark testers because they only tell you IF there's a spark, not how strong it is.

But.... unless you've got the wrong plug in there completely, I really do not believe you have a spark problem. You would notice drivability/power issues outside of just bogging under full throttle. I really believe you have a carb issue that needs to be ironed out... Feel free to check the ignition components if it makes you feel better but personally I would focus on the carb.

Also it is worth double checking to make sure the exhaust is not restricted (I can't remember if you checked that or not). IF the exhaust is restricted, it can cause identical issues and cause it to load up with excess fuel as well if the exhaust gases have nowhere to go!

[YamaKart]

The spark plug is the one called for in the service manual. From memory it is something like NGK BRP2ES or something like that. Gapped to manual specifications. I've got the official service manual for the cart which has specifications, torque specs, part numbers, etc. No, I have not removed the muffler and components to check for an obstruction. How would one know it's obstructed, this is uncharted territory for me. BTW, I've got a "tool" that allows you to attach via clip to ground, then put the other end into the spark plug wire, then you can set the tool's "gap" and fire it up! Watch for spark.

[CP241]

Ok, I don't recall reading what spark plug you were running, just that it was new.

For a quick test, loosen the bolts holding the exhaust to the head (don't completely remove, just loosen them a bit). You want to create a gap and allow the exhaust to escape/bypass the muffler. It's going to be quite loud, but take it for a run and see how it behaves. if it makes a big difference, then the muffler may be the problem, or at least a part of it.

Yamaha packed these things with fiberglass and stuff to make them super quiet (it works). But quiet doesn't always equal airflow, and if things deteriorate and start causing it to become even more restrictive, then it creates problems. I've seen some guys cut the muffler open, remove the baffles, and then weld it back together. Other folks just replace the muffler. IF the muffler is the problem, i'd see what plowman's has to offer. Their performance muffler is $399, or the entire hot setup is $599. Worth the extra $ if you ask me to do the whole thing.