How to Convert a Honda GX50 to Run On E85 85% Ethanol

[Fatbike]

I want to covert a Honda GX50 to run on E85. I do not want to debate the politics or negative reasons to not use this fuel. Brazil runs on E85 (and higher) ethanol engines for decades now. E85 works excellent IF done properly. My personal reason to run E85 is that I can get it 1/4 mile away, and I want the clean smell it leaves behind vs gasoline. I have an aversion for gasoline fumes, or having that smell cling to my clothes and skin.

I've read there are two ways to do this. 1) Mod the carb jets to intake more air. There is a basic formula for this somewhere. 2) Lengthen the intake manifold? <-I could be mistaken. I thought I read something about this.

Also, the motor may need some seals/gaskets replaced, though I've read modern gaskets should work.

Amazingly, I find little information on the net how to do this on this popular motor. I have found info about buying carb-kits for Go Kart racing to mod those larger motors to run on methanol-nitro or e85.

Unfortunately, I'm not a motor expert or have the personal knowledge/ability to understand how to do this. I would prefer to just buy a kit that would work, but it looks like I'm going to need some expertise & help to guide me to where I can get that help and information.

Can anyone help out?

Thanks.

 

[darwin]

Thers a huge debate between industry/oil cos and the enviro Nazis going on about this right now. Industry says its not good for small engines/older autos and the Nazis say we don't care. Choose a side. Alcohol is corrosive on metals too not just gaskets and plastic/rubber parts.

 

[Fatbike]

Thers a huge debate between industry/oil cos and the enviro Nazis going on about this right now. Industry says its not good for small engines/older autos and the Nazis say we don't care. Choose a side. Alcohol is corrosive on metals too not just gaskets and plastic/rubber parts.

This thread is strictly supposed to be about a "how to" guide with ideas how to do a Honda GX50 e85 conversion. See again OP. I hope we don't get sidetracked. Again, Brazil does it on a national scale with car engines and Go Kart engines too. E85 is used in race car engines in the USA too. I'm certain it is done in Brazil with these small Honda engines too. It can be done successfully with the correct mods.

I'm willing to buy an engine to convert, but I'll need some advice about doing the conversion. See OP 'why' I'm not going to use gasoline except the small amount that is in E85.

Please, let's just focus on the conversion. Politics, Pros/Cons... I'm waayyy past reading about it. No need to clog this thread "off-topic" about such issues. Thanks! Sincerely.

 

[darwin]

When addressing OP your addressing yourself, sort of redundant......If I were you I'd bing corrosive resistant rubbers, metals and plastics for use in small engines. Then you'll have a knowledge base to start from to make your own parts and be ahead of the curve that a billion $ industry says is detrimental to their products. Good luck in your endeavor.

 

[Purple Haze]

The Honda GX50 is a quality engine sold around the world. I don't see any problem using E85 with it. The carb jetting may pose tuning issues, though. E85 has less energy (btu) than straight gas, which could cause a lean condition. If you can find larger jets for the carb, it would be an easy fix. One other thing to consider; ethanol has higher octane than normal pump gas, therefore you could run higher compression to get more power without knocking, up to about 13:1. Don't worry about any plastics, most everyone uses plastic gas tanks, and they hold up much better than the old metal ones ever did. Good luck with your project.

 

[Fatbike]

The Honda GX50 is a quality engine sold around the world. I don't see any problem using E85 with it. The carb jetting may pose tuning issues, though. E85 has less energy (btu) than straight gas, which could cause a lean condition. If you can find larger jets for the carb, it would be an easy fix. One other thing to consider; ethanol has higher octane than normal pump gas, therefore you could run higher compression to get more power without knocking, up to about 13:1. Don't worry about any plastics, most everyone uses plastic gas tanks, and they hold up much better than the old metal ones ever did. Good luck with your project.

I went over to the Go Kart forum at http://4cycle.com and I found this about modding a Briggs & Stratton 4cyl Engine for racing on methanol, which is more "corrosive" than E85. I think these are excellent ideas to prevent residue varnish/water damage if the motor is not used at least weekly with fuel being used-up per tank at least monthly & preferably asap... as can be seen below carb-kits are available to do this too.

For the "average" racer that wants to build his own carb for the stock unrestricted class but doesn't have a clue about it. Buy the alky jet kit from Briggs. Put the .40mm pilot jet in and the 1.35mm main jet it. Install the alky fuel nozzle that is in the kit. Set the float height at .860". Use the ORIGINAL gas needle (BGB needle) and set the clip in the #5 (bottom slot closest to tapered end) position. Set your idle mixture screw (small screw closest to air filter) at 3/4 turns out.

That setup works without any other drilling or any other modifications to the carb and is a darn good setup that has won a lot of races for a lot of racers and shops.

Things to watch on the PZ carb is the floats and the inlet needle. If you race the Animal a lot, go ahead and buy a few extra inlet needles, they are cheap. Go ahead and keep an extra float kit also.

The inlet needle is important. All the fuel that gets to the engine must pass through here. If the carb/needle does not get flushed properly it can swell up and restrict fuel flow. The spring in the needle also gets week. I replace them at every rebuild whether they need it or not. It's a cheap part that can ruin your day so it's better to just change them.

After watching the floats for a while in several motors and comparing notes with other builders, I can not figure out why, but the floats actually gain weight over time. Don't believe me, get a gram scale and weigh your float. Go run it for a month or so and then pull it back out and weigh it again. I can't explain it, but I have to assume it affects the tuning of the carburetor so they also get changed at every rebuild.

There is a lot of debate about what is best to "flush" your carburetor with after the race day is done. Gasoline, Gasoline with a 2cycle oil mix, Gasoline with Marvel Mystery Oil mix, and WD-40 are probably the most I hear about. I have used them all with good success. The only problem I have seen is if you fill the carb with Gasoline or any of the Gasoline mixes make sure you leave the carb bowl FULL of fuel until the next race. If you drain the carb bowl and let it sit around for a few weeks the left over fuel droplets evaporate and leave a varnish looking coating on the carb bowl and carb parts.

If you plan on storing the engine for over a month I recommend pulling the bowl off the carb and spraying WD-40 through ALL the holes in the carb to completely flush out any methanol or gasoline or any other liquid you have in your carb. Make sure ALL the gasoline and methanol is gone. Clean out your fuel lines and fuel pump also. Anywhere gasoline or methanol can accumulate during engine storage is a BAD thing. Make sure they are clean.

Now, I have been told by a few people they are using Gasoline with Stabil additive and that keeps the gasoline from going stale and leaving the varnish finish. I have not personally tried it for myself so I don't really know but sounds like a good idea.

 

[darwin]

This article is from Consumer Reports which is a neutral party to the issue. Notice towards the end of the article the mention of E85 dissolving fiberglass gas tanks. http://www.consumerreports.org/cro/...nol-a-problem-for-small-gas-engines/index.htm ...................OP my point is not to criticize your attempt at improvements to your small engines, rather I wish you success. My point is E85 is so corrosive the materials to deal with it aren't on the market yet. New car warranties , Extended warranties , small engine warranties are all voided by use of E85. You can bet the best scientists on the planet are working on the problem but the answers havn't been found yet. http://www.politicolnews.com/new-e-15-ethanol-gas-will-invalidate-car-warranties-in-pre-2012-cars/

 

[Fatbike]

I found this on the Go Kart site (link in my post above) about converting the Honda GX50. Though this person did not actually do a conversion.

Converting the honda to alky is a much better idea, 4 strokes are simpler, measure the carb's main jet orifice size, then find it's area, ( pi x (radius x radius)), multiply this by two to double the area, convert the new area back to diameter ( square root of the area divided by pi ) and drill it up the jet to this size, you need to double the AREA of the jet not the diameter, raise the compression ratio to take advantage of the alky's 120 or so octane and advance the ignition using an offset key in the flywheel, that's all, a tuned exhaust would help also but the noise might be objectionable, use a good non restrictive air filter, I would not recommend installing a bigger carb since you may loose the little low end torque this toy motors have.

 

[Fatbike]

My point is E85 is so corrosive the materials to deal with it aren't on the market yet. New car warranties , Extended warranties , small engine warranties are all voided by use of E85. You can bet the best scientists on the planet are working on the problem but the answers havn't been found yet. http://www.politicolnews.com/new-e-15-ethanol-gas-will-invalidate-car-warranties-in-pre-2012-cars/

What you suggest above is not accurate. Research Brazil and E85. A whole nation with a land mass larger than the USA runs on it. Back in 2009 a Honda E85 150cc bike was already being sold in Brazil much more so than the gasoline version.

Brazil, March 11, 2009 - Moto Honda da Amazonia Ltda.(HDA), a Honda subsidiary in Brazil responsible for production and sales of motorcycles and power products, announced it will begin sales in Brazil of the flex fuel CG150 TITAN MIX in mid-March 2009. This small-sized motorcycle is equipped with a Mix Fuel Injection System, a flexible-fuel technology developed independently by Honda. This is the first motorcycle in the world to be equipped with flexible-fuel technology.

John Deere is now making E85 mowers for the USA:

John Deere has introduced a brand new riding mower that can run on up to 85% percent ethanol blended fuel.

The mower is a new Flex Fuel model of John Deere’s popular line of ZTrak mowers. The new, industry exclusive, Z925M Flex Fuel gives landscape contractors and customers with large acreage to mow a new alternative fuel option for their fleets.
“As we see E85 blends take off there is going to be a need in the market for this type of machine,” said Steve Wilhelmi, John Deere tactical marketing manager. “In addition, it just helps our alternative fuels platform” which includes electronic fuel-injected engines and biodiesel kits for diesel machines. Just another way to support the farmers who grow the crops that produce those biofuels.

The new Flex Fuel model is part of the M Series of ZTrak commercial mowers, designed for customers seeking productivity and efficiency. With a 24.6 hp* electronic fuel injected engine, the Z925M Flex Fuel can run on any blend of ethanol-mixed fuel, up to E85, and it has a top speed of 10 mph. Offered in 54- and 60-inch widths, it comes equipped with a 7-Iron™ deck, for maximum durability. Enhancing operator comfort, the new model offers the option of an isolation seat or a fully-adjustable, suspension seat. For easy cleanup on the jobsite, an optional, integrated material collection system provides a Dump-From-Seat option for enhanced ease of use. Finally, the Z925M Flex Fuel comes with a class-leading 3-year/1200 hour warranty.

Flex Fuels are American as Apple Pie: "The first commercial flexible fuel vehicle was the Ford Model T, produced from 1908 through 1927. It was fitted with a carburetor with adjustable jetting, allowing use of gasoline or ethanol, or a combination of both."

Yep, Henry Ford, well known for his advocacy for ethanol, not gasoline, knew a lot about engine wear/tear 100 years ago!!! He knew a lot about engines, so let's drop the BS. It has been done, it is being done now, and it will be done too. This is NOT rocket science! Let's stay focused on HOW TO MOD A GX50 for E85.

What actually works?

 

[professor]

Well, just open up a spare jet and go for it. Cars run on it and they don't change compression ratios.