Engines Propane Conversions. Lawnmower, tractors, generators, pumps, etc...

[Vlad]

After some very successful propane conversions I decided to share the info I have. I found people spend a lot of money converting their lawn tractors to electric motors. Propane conversion will cost you from nothing (yes you have all this junk in your garage) to couple hundred bucks if you want to be very sophisticated.

[S-F]

I have browsed the internet to find conversion kits for my lawn mower. Unfortunately I'm using the ICE mower again because i don't have the time to keep up with the lawn and the push reel mower. There are a bunch of ghetto conversions out there where people just pulled the carb off and stuck a hose in the intake. There has to be a more sophisticated way of going about this. How'd you go about converting all of your engines?

[Vlad]

Here is some background info:

I used to work as motorcycle, marine, small engine mechanic at Honda for over 6 years. I know small engines very well.

Ones we sold to one customer a bunch of Honda EU3000 generators. This customer wanted to have one of the generators running on propane. The big boss (owner of the company) decided that it was an easy job and promised him conversion. The big boss ordered one of the complete propane conversion kits for Honda engine.

When kit arrived he had a dilemma how and who was going to do this. He knew I love all kind of non standard stuff. So he gave me the kit and some VERY STUPID instructions. It was almost impossible to use this instructions. I took some time to find info and converted generator. Customer was very happy and asked us to convert the rest of his generators..... . For me it was fun because I really love to do new things....

From that moment he had somebody who could convert small engines to run on propane.

[Vlad]

Now let's see what options you have:

1 Monkey ghetto conversion

2 Proper right way

I have tried them all.They all have pros and cons.

Lets see the ghetto one first.

There is only one pros - cheapness. The rest are only cons.

Let's see how small engine works. Most small engines run on constant RPM. Engine load constantly changes. Governor(usually centrifugal type) is trying to keep the same RPM by adjusting throttle angle (open and close). When throttle is opened engine gets more air flow in carburetor. This increased air flow will "pull" more gasoline from emulsifier tube. In this case air/ gasoline mixture is mostly balanced most of the time. When throttle is closing the process works the other way.

Now with our ghetto conversion we have some kind of pressure regulator (to reduce pressure of liquid propane to very low pressure) and some kind of adjusting valve. We have no gas flow control. We deliver the same amount of gas all the time. But engine's governor constantly changes throttle angle. We have imbalanced fuel air ratio and engine starts surging and backfiring and running like s...

Also it is usually hard to start engine that is converted to run on propane this way. You have to keep adjusting the valve to make engine run better but it will run OK and suddenly start running like s...

Here is an example of components I used for ghetto lawnmower conversion:





You can see adjustable propane regulator on right side (all small BBQs have them) and valve from propane BBQ. I brazed a small barb tube to the end of valve to connect hose that was going to carburetor.

Easy, free in most cases but don't expect your engine run smooth and efficient.

Here are some examples of this type of conversions

http://www.youtube.com/watch?v=kmf3DBG_iVg

http://www.youtube.com/watch?v=wg0C1...feature=fvwrel

Here even child cold convert his lawn mower to propane

http://www.youtube.com/watch?v=mI6ap...eature=related

But again you can tell all this engines don't run properly and if you have not perfectly straight lawn you will end up adjusting the valve all the time.

Propane consumption in this types of conversion was 2-3!!!!! times higher compare to a proper conversion.

My 6hp Brigs lawnmower consumes less than 1lb (about 13 oz) of propane in full hour. It runs just perfect (much better than on gasoline). Starts every time from first pull.

[Vlad]

Now let's see how to make small engine run perfectly on propane and if you need on gasoline as well.

All my converted engines can run on gasoline or propane.

Here are major components you need to convert your small engine to propane (also there are some "accessories" for safety and easiness of use).

1. Propane tank. I prefer using 16 oz containers for lawnmower (they are easily refillable) and 20 lb BBQ tank for larger applications

2. Special pressure regulator (called zero governor). This is a special regulator it has very sensitive diaphragm that senses very low vacuum from carburetor (venturi effect)and supply correct amount of gaseous propane. This regulator doesn't supply propane until engine creates vacuum.

Unlike in previews conversion now we have device that senses engine fuel demand and supply right amount of fuel (gaseous propane) all the time.

3. We need some sort of restrictor because zero governors are made usually for a wide range of engines (5-15 hp or 5-25 hp or 10-40 hp etc.). You can use ball valve or just a T with a bolt in the middle for restriction or some sort of valve. You need to set it up only ones when you run your engine on full power.

4. You need some sort of delivery device that delivers propane into carburetor. This part is one where you have to use your brain.

You can buy a special adaptor that is made specificly for your engine. This is the best way but if you want to save some $$ it is easy fix part.

[Daox]

Could you explain the benefits of doing a propane conversion on an engine?

[MN Renovator]

The only benefit that I see is that you don't have to deal with fuel preservation issues of gasoline with ethanol where the fuel gums up over time and clogs carb jets. Also don't have to deal with grabbing a funnel, cleaning the all the accumulated crap out of it and pouring gas. I wouldn't mind running my lawn mower and snowblower off of propane and ditching the gas cans altogether. ...I decided to go battery electric instead but the electric snowblower is still a work in progress due to costs involved with getting the right capacity and voltage of LiPo batteries for it and a good relay that can handle switching the DC voltage on and off. The battery lawn mower works great though although I'm currently looking to replace its charger to a simpler single-unit one which is in the mail on its way to me at the moment. Propane would be cheaper though but I like to snowblow and mow the lawn on my schedule which is offensive to the neighbors when its too early in the morning and they are sleeping if I'm looking to do it when the sun is rising and the temperatures are still comfortable outside on a hot day.

[randen]

Switching a snow-blower to propane may not work so well as you need heat to keep the propane vapourizing when it gets cold. Electric mower and a stealth snowblower sounds very cool.
I agree with Vlad propane has some definite advantages. The equipment that runs on it are cleaner. Its also a great refrigerant.

Randen

[Vlad]

Originally Posted by randen

Switching a snow-blower to propane may not work so well as you need heat to keep the propane vapourizing when it gets cold. Electric mower and a stealth snowblower sounds very cool.
I agree with Vlad propane has some definite advantages. The equipment that runs on it are cleaner. Its also a great refrigerant.

Randen

Remember propane evaporates at -42C. You can always make a heat exchanger from 2 copper tubes and use hot engine oil to heat propane. I had problem with my loader. Propane was splashing while I was operating the loader. Liquid propane was freezing pressure regulator so I made HX from 2 tubes and used oil from transmission to heat up and evaporate liquid propane. It works just fine after this. I will post some pics.

We are DIY we use our brain right ???

[Vlad]

1 Propane VS gasoline

1. No carburetor issue every season.
2. Oil change only once a season
3. Virtually no carbon monoxide poisoning.
4. Cheaper to operate.
5. Much more environmentally friendly.
6. Engine runs clean no smell no carbon.

I have 6Hp Brigs lawnmower (the older one I paid 50$ for it). It takes me an hour to cut my lawn. Usually I had re refill it every second time (4l of gasoline @ 1.4$ per liter. Yes it is Canada 1.4x2=2.8$ per lawn cut).

Now I cut the same lawn. I need 13 oz of propane to do the same job (78c per liter. 1l of propane= 33.8 oz. 33.8/13= about 2.5 Then 78c/2.5= 31c )

2.8$ VS 31c. It is almost 10 times difference when it comes to fuel price. It is true for Canada. I know in US gasoline is much cheaper but you can't beat propane...


2 Propane VS electric

1. Conversion is much cheaper. I spent about 60$ to convert my lawnmower and 120$ to convert my skid steer loader (Case 1816c).
2. No winter maintenance. You have to charge batteries all the time.
3. No extra cost. You have to replace batteries (and they are not cheap) every 5-6 year.
4. It takes just few hours to convert lawnmower or tractor vs ????
5. Convenient power expectation and operation
6. No time limit to run (you have to charge batteries) . Just refill.

I am not taking corded lawnmower because they are a real pain to operate.