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Old 02-11-2020, 11:27 PM
DugT DugT is offline
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Default Modding a Honda GX200 snowblower at 6000' elevation???

I would like to get more power out of the Honda GX200 in my snowblower. At sea level it would probably be powerful enough but I live at 6000' so the power is reduced by about 18%. What are the disadvantages of just cranking up the RPM's? The max RPM spec is 3600rpm but increasing it seems like the easiest way to make it more powerful.

Here are my questions:
*How much can I increase the RPMs before there are diminishing returns?
*Is there a weak link like the rod or flywheel?
*How much can the RPM's be increased without need to mod the air flow?

Thanks!
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Old 02-12-2020, 05:13 AM
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So your saying you want a racing snow blower lol?
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Old 02-12-2020, 06:55 AM
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You CAN adjust the governor, but it actually doesn't change the power, it just makes it rev higher.
Governors can only be adjusted to about 4200 RPM if I'm not mistaken. But I wouldn't run the engine at those speeds, because like you're asking, the rod and flywheel are indeed weak points that can fail at high RPM.
IDK what a stock flowing GX200 can rev to.

Does it just not throw snow far enough?? If I'm not mistaken you can run it without an air filter, but only in freezing temps. That boosts flow, and if you're willing to make it loud, you could slap a header on there instead of the muffler. That will require richer jetting, but it should give an impressive power boost.
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Old 02-12-2020, 07:57 AM
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Quote:
Originally Posted by JTSpeedDemon View Post
That will require richer jetting, but it should give an impressive power boost.
Typically engines run rich at higher elevations to begin with.

Unfortunately, with less air to consume, nothing you do will have the same effect that it would at sea level (except turbocharging). Usually the performance of a snowblower is most improved through enhancements to the blower itself, not the engine. Making it spin faster by tweaking the governor can actually hinder performance, as increasing the RPMs increases the snow throughput, while simultaneously dropping the torque curve. Essentially, trying to do more with less.

What type of blower is it exactly? Single stage? 2 stage? Self propelled?

And what sort of improvements are you looking for? Increased throw?
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Old 02-12-2020, 07:59 AM
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Good point though, I was still a little sleepy when I posted that.
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Old 02-12-2020, 08:40 AM
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The blower is a Honda HS724. It is about 15 years old but it is in excellent condition and the auger and tracks have little wear. I only use it on a deck and sometimes it doesn't blow the snow far enough to clear the 3' fence. I just finished the Impeller Mod (added rubber flaps so the impeller blades extend to the cylinder that the impeller is in) but I haven't tried it in snow yet. Its likely the impeller mod will solve the problem.

While investigating the impeller mod I got curious about increasing the rpms to increase the power. I know just enough about this to be dangerous so I appreciate your input. I asked about this in a snowblower forum and they agreed with what has been said here but none of them had experience with higher rpms in a snowblower.

Thanks!

---------- Post added at 09:40 AM ---------- Previous post was at 09:30 AM ----------

Both of my snowblowers don't have air filters. I don't want a loud exhaust. The HS724 is two stage.

I recently bought an HSS1332ATD for my driveway and I was considering increasing its RPM's too. I haven't even tried it yet because it hasn't snowed here in Truckee (Tahoe) for over a month.

I think I've answered all of the questions.
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Old 02-12-2020, 08:03 PM
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Good news! I think the cable that adjusts the engine speed is too slack so full throttle is only about 80% of real full throttle. Immediately after that discovery I had to leave but tomorrow I will adjust the cable. The blower is 15 years old so maybe the cable stretched.
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Old 02-12-2020, 09:12 PM
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Yep, get your throttle cable working correctly for starters.

If you want a little more impeller speed, a subtle pulley swap would be more effective than over-revving the engine. Make sure whatever mods you do ONLY increase the blower speed and not the drive speed as well. Speeding up the drive might not hurt with small snowfalls, but moving large amounts, you may find that you can't drive slow enough to keep from overloading the blower.


Most gains beyond that will come from operating technique.

Coat the inside of the blower housing and chute with a silicone based spray lubricant before use.

Try keeping your chute turned the same direction as the impeller rotation as much as possible. It sounds silly but it makes a difference. On most machines that will be to the right.

Try to keep the impeller good and loaded up if possible. It's a centrifugal pump pumping a (somewhat) fluid substance. Think about what happens to a water pump when it starts sucking air.
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