Originally Posted by PJMac (Post 2391216)

We had exactly this problem. Clogged exhaust. Apparently they make these quiet by packing a lot of insulation in the muffler. It can work itself loose. Replace muffler.

Do not remove spark arrester. Can’t believe I had to say that.

Originally Posted by SteveCanada (Post 2391182)

A 2017 Yamaha quiet tech.. runs great at 21 mph on flat but slows on incline .. going over bridge at Spanish Springs slows to 5 or 6 mph on steep incline .. is this normal or is my belt needing change etc ? thanks

Originally Posted by CarlR33 (Post 2391186)

Ever had any maintenance done on this vehicle like a belt change? If not, that may be your answer?

Originally Posted by mrf6969 (Post 2391193)

You need to remove the spark arrestor. A spark arrestor screen is a device designed to prevent fires by stopping sparks or flames from escaping. There are two common types:
Screen type: Uses a metallic mesh to prevent large particles from leaving the exhaust system. Commonly used on motorcycles, ATVs, golf carts and small engines.
Known to cause your issue.

Originally Posted by mrf6969 (Post 2391193)

You need to remove the spark arrestor. A spark arrestor screen is a device designed to prevent fires by stopping sparks or flames from escaping. There are two common types:
Screen type: Uses a metallic mesh to prevent large particles from leaving the exhaust system. Commonly used on motorcycles, ATVs, golf carts and small engines.
Known to cause your issue.

Originally Posted by tophcfa (Post 2391237)

Definitely could be the spark arrestor. In general, QT’s don’t have a lot of power relative to other carts since they have a smaller HP engine as part of the design to make them quiet. Also, the spring in the secondary clutch is designed for golf course use where the carts don’t go more than about 12-14 MPH. Yamaha adds high speed gears to their Personal Transportation Vehicles used in the Villages, but doesn’t modify the clutch spring. Adding the high speed gears increases top end speed but can compromise torque (start up speed and hill climbing power). An easy modification will solve the problem, which involves putting a stiffer spring in the secondary clutch and replacing the belt with a premium aftermarket drive belt. I did the modification to our QT using the green spring and premium belt available from powerequipmentman.com and there is a noticeable performance difference (not top end speed, just torque). The website also has an excellent YouTube video showing how to do the modification. It does require some basic mechanical knowledge, and two specific tools that most people don’t have, a clutch compressor and a snap ring tool. My neighbor up north loves to fix stuff and helped me fabricate the clutch compressor and let me borrow his snap ring tool. I’m very happy with the modification, but the cart definitely was a little jumpy for a couple days until the new belt broke in. I keep the old belt in my cart as an emergency backup and hope to be able to use it someday to help someone stranded with a broken belt.

Regardless of the problem, it’s a good idea to remove the spark arrestor next time you change the oil and you have easy access to it. You will be eliminated a potential future problem that is only there because of a stupid California requirement. The cart will run better and you will only notice a slight increase in noise when driving through tunnels or alongside a dividing wall.

Originally Posted by polirudb (Post 2391474)

I had the same issue and one of the local companies came to my house and removed the spark arrestor without telling me what they did. There was definitely a big positive difference in performance, especially crossing the Water Lilly bridge. The noise from the cart however was almost unbearable. I called them back, and at the time they told me the only solution was to put the spark arrestor back in (which again I did not know they had taken out). When I told them to put in back in, they told me the cost would be about $700.00, as a new spark arrestor is only sold with the muffler assembly. After much back and forth, they finally "found" me a spark arrestor (probably one they removed from someone else's cart), installed it in my cart, and my problem was solved. Bottom line, in may case, removing the arrestor improved performance but increased the noise the cart made to the point that it was no longer a "quiet tech". Cleaning it, if possible, or poking holes in it as some have suggested, may be the best answer. Good luck!

Originally Posted by SteveCanada (Post 2391182)

A 2017 Yamaha quiet tech.. runs great at 21 mph on flat but slows on incline .. going over bridge at Spanish Springs slows to 5 or 6 mph on steep incline .. is this normal or is my belt needing change etc ? thanks

Originally Posted by Wenham (Post 2391469)

Is this used to prevent fires onboard the cart or to the environment.
Will this definitely improve tourque on steep grades?
Also, any risk of damage to the cart?

Originally Posted by tophcfa (Post 2391531)

The spark arrestor is designed to prevent a spark from coming out of the muffler and starting a brush fire. It is basically a fine screen that covers the end of the tailpipe. Over time, carbon deposits clog the screen and limit exhaust airflow causing performance issues. For the Villages usage, it is a worthless and trouble prone feature. Kind of like an appendix or wisdom teeth in a human. If all the idiots driving around tossing out cigarette butts hasn’t started any fires than spark arresters most certainly aren’t necessary. Removing the spark arrestor will only help climb steep grades if the one in your cart has become clogged. There is no risk of damaging your cart by removing it, but it would risk damaging your cart driving around with a badly clogged one. Hope that answers your questions.