G1 exhaust ideas

[mike w]

My cart is used for recreation After the rebuild I did away with the premix pump. I now premix the gas. I mix at 80-1. I have bought a new exhaust muffler and ran a 1 inch I'd flex exhaust to the back of the cart. The problem is who ever sits on the back complains of the exhaust smell. I'm thinking of hooking the pump back up because I know this works of the speed of the engine. The smell is real bad at take off or at low speeds. Thoughts and ideas are more than welcome. What's the id of the hose for the injector pump? Thanks Mike

[Lochlin]

Think it might be a simple fix to just run your flex pipe out of one the sides of you cart? 1 inch is already pretty small but you could potentially reduce that just a bit more (not much though, see next paragraph) so that the exhaust blows farther away from the cart. Maybe try to revert to original placement?

Regarding the muffler, is your new one a G1 replacement muffler or something else you made fit? Reason why I ask is that mufflers on 2 stokes are not only for noise suppression. They are also needed to maintain proper case compression / vacuum. This is why I would be leery of reducing your 1 in pipe a whole lot as it could affect engine performance. There is a balance there that needs to be maintained.

Indeed, the auto-oilers increase / decrease oil with engine RPM but this same thing happens when you mix gas as well......faster speeds get more oil as the engine needs more gas. If working right, that auto-oiler should be mimicking that action. The ratios should be the same either way. All the auto-oilers do is mix the oil / gas rather than the owner having to do it. That 80/1 ratio should be consistent at all times, auto-oiler or premixed.

[mike w]

Thanks for the response. The new muffler is stock. I used a caliper to measure the outside diameter of the exit pipe that is 1 inch. I'm a little puzzled by your response on the mixing ratio. If I mix the gas at 80.1 wouldn't it be 80.1 all the time slow and fast. My understanding of the pump is it progressive off engine speed. That being said the mixture would be less at take off?

[Lochlin]

This is a confusing topic but, yes, mixed gas retains the same ratio, slow or fast.

It may be helpful to, rather that considering the mixed gas, consider the function of the auto-oiler. When the cart is running slow it is using less gas. In turn, like you say, the auto-oiler is adding less oil to that lessor amount of gas that the engine is using. As the engine gets faster, the oiler adds more oil to maintain the proper ratio. So, when the engine is running slow, the carb is calling for less gas, and the oiler is injecting a smaller amount oil to maintain that 80 to 1 ratio. When the engine is roaring it is using a lot more gas and the oiler is injecting a lot more oil to maintain that 80 to 1. Fast or slow, the fuel that is being combusted in the cylinder is mixed at 80 to 1, the same as mixing it yourself to begin with.

Now, a lot guys, me included, disconnect those oilers altogether. The reason is that, over time, the engine vacuum needed to make sure those oilers are functioning at the "80 to 1" level degrades which causes the oilers to function at a less than 80 to 1 level and that's not good for the motor, obviously. When you pre-mix you get guaranteed 80 to 1 which is why a lot of people go that route.

If you consider the pre-mixed gas similar logic applies. When the engine is running slow it is drawing less gas / oil mix which, ultimately, means a lessor total amount of oil. When running fast it is drawing a lot more gas / oil mix which, ultimately is more oil than when the engine is running slow (even though the ratios are the same for either speed).

[Spicyunicorn]

You're going to have exhaust smell regardless of oil mixture just because it's dumping out the back.... take the extension off never had a problem with stock exhaust smell...That being said run it at 100:1 it's a happy medium and minimum smoke

[sho305]

I thought the injection was 100-300:1 or something, its not much oil IIRC it runs off the pulse of the exhaust pipe or that causes it to oil more at high throttle, etc. I mean you hardly ever have to put oil in the injection.

Either way its a 2 stroke and its going to stink. Best thing I would think is get a good synthetic they burn cleaner and smoke less and lube better, use less like 100:1. Make sure every few hours of use you run it for a while to heat the muffler if you normally short trip the cart, need to get it hot to keep the muffler clean. If you take longer rides its not necessary.

Or move on to a 4 stroke cart, even those when they get tired can stink a little but usually only when you go fast and slow down/stop then get the backwash.

I know a guy that ran the pipe out the rocker on the side, said it helped but still got it sometimes.

[cgtech]

One tank of Oil is supposed to last 10 tanks of fuel.

[mike w]

Thanks for all of the responses. We take long trips at least 25-30 minutes. The exhaust is a plowman exhaust. I still have the injection pump on the cart. I'm going to put oil back in the tank and run it into a clear pop bottle and make sure the pump is working properly. Then drain the gas tank. I'm going to remove the extension from the exhaust and see if the smell is better. I'll keep everyone updated. Sho305. I've read post from you before. You are not a fan of premix correct? Thanks again everyone

[Lochlin]

Originally Posted by sho305

I thought the injection was 100-300:1 or something, .

Not sure. I actually run 100-1 as I have a few other carts and some other 2 cycle engines (weed whacker, chain saw, etc.). It seems as if 100-1 is average for all of them so that's what I go with rather than having 5 different gas tanks with 5 different fuel mixes laying around.

[mikeasis]

So far im having good luck with VP synthetic i buy at wal mart. its not cheap but i want this ole gal to last.