Yamaha G22A hesistation at higher speed, engine hot/overheating?

[Yamaha357]

Hello everyone,

New owner here of a 2002 Yamaha G22A with the 357cc 4 stroke engine. Purchased this cart in a non running state and have got it up and running smoothly and now the modding has begun.

I was initially able to get the cart to 18mph by adjusting the 10mm throttle cable at the governor, but had intentions of making this cart street legal, so 25 mph was a must. In my hunt to achieve these speeds I decided to bypass the governor and am happy to report speed is no longer the issue, able to hit 27+mph with ease (of course watching out for engine speed/overrev).

The thing I have noticed is during longer drives (1 mile+) and speeds above 20mph, I am getting a hesitation/stumbling. Seems like it would likely be due to a potential overheating issue from the increased speed and load on the engine. I have replaced the engine oil, new air filter, new spark plug and new battery. Next steps are to clean or replace the carburetor and replace the fuel pump as a precaution.

Seeing as this is an air cooled engine, is there normally some ducting to force cool the engine while driving? I have not noticed any am thinking of making my own with some sheetmetal to combat the Arizona heat the cart will face. A blocked muffler or dirty carb were my other thoughts as do why the hesitation, but figured I would reach out here for others who are experienced with modding these for higher speeds to learn of any hurdles that could go along with them.

Thank you for any thoughts in advance, excited to join this forum and learn some more about these carts.

[Dave in VA]

There should be shrouding around the cylinder head, and a rubber boot between the shroud and the muffler. Air is forced around the head and muffler.

[Dave in VA]

Clean and rebuild the OEM carb. Aftermarket ones are usually junk.

[Yamaha357]

Dave, thank you for the pictures, much appreciated. I do have the shroud as pictured and the rubber boot between the head and muffler. Perhaps some additional ducting up front to help direct more air would be sufficient.

Any experience with stumbling issues at higher than normal speeds? I'm not ruling out the carb yet (and will take your advise on clean/rebuild), but am a little skeptical on the stumbling only occurring at higher than stock speeds for a prolonged period. With the engine cool, I can run smoothly to 27mph without issue, just after a while I start to hesitate and stumble.

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[Dave in VA]

Additional ducting isn't necessary. Pull off the shrouding and clean out the fins on the cylinder. You'd be surprised how much crap will accumulate there...

[Dflowe]

An engine running lean can cause hotter engine temperatures. I agree with Dave in VA, that a clean stock carburetor is the way to go. Stumbling could be caused by a lack of fuel and explain lean conditions as well.

[Yamaha357]

Thanks for the help guys. I removed the shroud and boot to check for blockage and it appeared pretty clean minus a few small leaves.

The lean thought is similar to what I was thinking and why I ordered a replacement pump to be safe, as I do not know the age or condition. Also went ahead and ordered the necessary rebuild parts for the carb, so looks like the last piece of maintenance I will be doing is the fuel system. While in there, I'll replace all lines as well. Glad to do it and start fresh with a newly maintained cart.

Hopefully I come back with good results later when I get the parts. Thanks again for the assistance.

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[cgtech]

There are only 2 things to do to the stock carb (assuming engine is stock). Needle valve and bowl gasket. I'm in the AZ desert too, the stock stuff works fine. (While there are plenty of really good upgrades available, but only to be done as a "system", not hap-hazzardly). Real high speeds do tend to be lean at highest speeds when totally stock, but they still run "fine" from a user standpoint. You have either "dirty carb" issues, or ignition issues. Ignition issues would be number 1 on my list based on your limited description (as I said, "a little lean" still runs fine as far as the end user would ever know). Bigger carb issues can easily be overcome with a real good cleaning. Not "I sprayed cleaner in it", every single bit has to be removed and individually cleaned. Every single bit, ("I couldn't get that part out, so I skipped it" does NOT count, and "I stripped it, but it will be fine" also does NOT count). And don't make the dumbest mistake on Earth and decide "I saw that whole thing on eBay for $27, why would I even deal with this one". Those China junkers are garbage, and far, far inferior to the original carb.

[Yamaha357]

Thank you again for all the assistance. Carburetor appeared to be the issue, smooth sailing now at 28mph for about a 5 mile drive without issue.

Now need to get brake lights up and running to attempt registration. Anyone have a link of feedback on what to use to add brake light functionality to my existing taillights? Is there a kit that can be purchased to complete this?

Also attached a picture of the new to me cart.



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[Yamaha357]

Originally Posted by Yamaha357

Thank you again for all the assistance. Carburetor appeared to be the issue, smooth sailing now at 28mph for about a 5 mile drive without issue.

Now need to get brake lights up and running to attempt registration. Anyone have a link of feedback on what to use to add brake light functionality to my existing taillights? Is there a kit that can be purchased to complete this?

Also attached a picture of the new to me cart.



Sent from my SM-G973U1 using Tapatalk

Sent from my SM-G973U1 using Tapatalk