# LP/NG regulators, kit or piece together? Honda GX690 & cheap 5-8hp units



## FlyFisher (Jun 30, 2018)

All, 

I picked up a new/never run 15k unit today - has a Honda GX690. I have a couple other smaller generators. One of those is a 3600rpm screamer and the other is an EU2200i Honda inverter. The rotaries I want to convert to NG/LP. I realize the fuel is different energy densities, and thus different air/fuel mixes. From what I have found the same regulators can be used for both types of fuel - provided that the air/fuel mixture has the adjustment range to tune it for the gas used. Is this a pretty accurate perspective? 

As far as propane goes - I realize the fuel line can't be connected directly to the tank as the pressure has to be stepped way town - similar to a portable heater, grill, etc that has a regulator at the tank. 

Are there any tidbits anyone can offer on the GX690 conversion? There are generator vendors that offer this unit set up from the factory (generator factory, not OEM Honda, at least to my knowledge) as LP/NG so I know it can be done, I just don't know if there is more to do to the engine other than pipe the regulated fuel in to the intake on the engine (IE - does the fuel pump need to be disabled when not running gasoline?). 

This is probably a dumb question, though I'll ask anyway. The smaller rotary I have uses a 5-8hp range single cylinder engine. I am not sure 100%, but it might be more of a B&S clone. I've rebuild the carb on it - pretty simple and reminds me of B&S carbs. In any event, could I get a couple of the same regulators and use them on both engines - the 5-8hp and GX690 (20-22hp)? The thought here is redundancy. If I can duplicate things that gives me the ability to swap if I need to.

As far as the kits go - I think the only "critical piece" to any of the so called "kits" is the adapter manifold in that they have to be specific to the type of engine it is going on. I can machine functional block manifolds myself and either source or make my own longer studs or extensions. I've seen some "fuel injectors" that inject LP or NG in the throat of the carb with a small tube. The tube blocks the choke plate so the ability to run on gasoline is severely limited. I am guessing the only reason that the "injector" style is out there is it leaves the carb in its original position = no adapter manifold required to mount underneath? I would imagine either method would do the same thing - it is allowing the fuel to enter the intake stream. 

Something I haven't quite wrapped my head around is the regulation of the fuel. As loading changes on the generator so, too, should the fuel. The higher the load the more fuel. When you set the air/fuel mix and have the unit running with no load - how does the regulator know to send more fuel to keep up with higher loads, and go back to lower fuel when the load is decreased/removed?


----------



## tabora (Sep 6, 2018)

FlyFisher said:


> has a Honda GX690








K9129 - K9129 Conversion Kit for Honda GX690 - Motorsnorkel by US Carburetion


K9129 Conversion Kit for Honda GX690




motorsnorkel.com









Honda GX690 Natural Gas or Low Pressure Propane Conversion Kit


Honda GX690 Natural Gas or Low Pressure Propane Conversion (Dual Fuel) Kit uses an adapter that makes it possible to operate natural gas and low pressure propane.




centuryfuelproducts.com









Honda GX690 Tri-Fuel (Natural Gas, Propane, and Gasoline) Kit


Honda GX690 Tri-Fuel Kit uses an adapter that makes it possible to operate an engine on natural gas and propane.




centuryfuelproducts.com


----------



## ToolLover (Jan 13, 2020)

@ Tabora: Am I wrong or is there not supposed to be a pre-regulator before this kit is connected to any gas source?
That information needs addressing also.


----------



## FlyFisher (Jun 30, 2018)

I would like to have more discussion than a list of products to purchase. I am a do-it-yourself'er and like to understand things. Both of those companies' regulator/conversion kits do not give a list of items in the kit. From what research I did the Century Fuel Products listings I did run in to. I was hoping to get some input as to the regulator in the kit, but they don't list that. So my question between running the two engines (5-8hp on the smaller unit and the GX690/20-22hp on the big unit) is still valid. 

I just checked the big engine. It has an emissions info sticker on it stating it complies with 2014 emissions standards. When I get it out of the truck I can look at it closer. I am not sure if the emissions standards change enough to date the engine to that year or not, but I was told it was about 3-4 years old. 2014 would put it back to 7 years old. Not a big deal to me, but it will make a difference in fine details on parts and those fine details could make a difference in the intake parts etc. 

I do not have any documentation for the unit right now. I will see if I can find some PDF's.


----------



## FlyFisher (Jun 30, 2018)

ToolLover said:


> @ Tabora: Am I wrong or is there not supposed to be a pre-regulator before this kit is connected to any gas source?
> That information needs addressing also.


As I understand it - both LP and NG will run, so long as they are "low pressure". If you are pulling from a high pressure tank (propane or CNG) you would need a "pre regulator", as you state. That "pre regulator" would step the pressure down for the supply to the regulator at the engine. 

The analogy that comes to mind is as I stated in my original post - grills, portable propane heaters, etc - they do not connect straight to a propane tank - there is a regulator between the tank and the supply line to the device. Then you regulate the flow at the device. The regulator between the tank and the device knocks the pressure down-stream of it down so the devices can work with lower pressure.


----------



## iowagold (Jan 22, 2020)

compliance to a standard by date is not the same as a mfg date code.
it just is older tech...
not the latest and greatest....

so fly you are looking for an education???


----------



## tabora (Sep 6, 2018)

ToolLover said:


> @ Tabora: Am I wrong or is there not supposed to be a pre-regulator before this kit is connected to any gas source?


Yes, the kit includes a demand regulator and will specify what the allowable input pressure is. For example, on my US Carburetion kit, natural gas uses 6-8 inches WC and propane uses 11-14 inches WC. So a quick-connect propane patio heater hose and regulator worked out fine.


----------



## tabora (Sep 6, 2018)

FlyFisher said:


> Both of those companies' regulator/conversion kits do not give a list of items in the kit.


US Carburetion has about 200 different kits for different applications including various combinations of fuels and dedicated high pressure kits. You need to browse around their site a bit and look at all the kit options to see what each kit includes. My snorkel kit contains all of this (the snorkel is specific to my LCT 414 engine, though):









A V-Twin kit with a double snorkel would look like this:


----------



## FlyFisher (Jun 30, 2018)

tabora said:


> View attachment 9251


What is part D in that kit? It is called a "load block" in that diagram, but I am having trouble getting any details. I assume it is another flow control valve such as a "needle valve".

I found some Garretsen KN style regulators for a decent price. I am showing the standard ones are for up to 30-40hp, which my engines are below that. Though, the regulators don't come with the brass valve on the output as questioned above. 

I can find all kinds of flow control valves but I'd like something better suited to the application that will allow locking with a jam nut once dialed in.


----------



## tabora (Sep 6, 2018)

FlyFisher said:


> What is part D in that kit? It is called a "load block" in that diagram, but I am having trouble getting any details.


It's exactly that (AKA mixture screw). You set it, lock it with the jam nut, and that's that... (AKA Bob's your uncle.) The vapor flow is established.


----------



## iowagold (Jan 22, 2020)

I like the ones from nash fuel better on the load blocks.


----------



## FlyFisher (Jun 30, 2018)

I can't find suitable valves available for a decent price so I am going to machine some. 90deg angle, a bolt, jam nut, and some washers (flat/split ring). We'll see how it all pans out. It will be a week or more before I get all the parts here.


----------



## FlyFisher (Jun 30, 2018)

1st attempt at a valve isn't very promising.





















I knew the rounded 90 would be a challenge but I gave it a go. I broke a drill bit and had trouble getting the tap to start. So I wollered out the hole a bit and ended up not giving the threads much meat. For low pressure it would probably hold, so it might actually work out OK. Though, the bolt only restricts flow so much. If that is still allowing too much fuel though then it it won't work. If it restricts enough and I need to back off it then it would work - just a pretty crude way to do it. 

I am thinking I might just get a chunk of aluminum to make some parts out of. I imagine 1" thick would work. These 90's are 3/8 NPT so that should leave enough material for that thread to work with a 1" block - both the valves and the manifolds.


----------



## iowagold (Jan 22, 2020)

use brass not aluminum when on LP or ng!

use a grinder to make a flat spot or use a mill cutter in a drill press with a multi axis drill press vice.
you can by those ready made you know!
pm me for links!
cost is under 30 bucks each.


----------



## FlyFisher (Jun 30, 2018)

iowagold said:


> use brass not aluminum when on LP or ng!


Thanks for the tip. What is the issue with aluminum? Does the gas corrode the metal?


----------



## tabora (Sep 6, 2018)

FlyFisher said:


> 1st attempt at a valve isn't very promising.


Why didn't you use a brass T like everyone else does, like what was pictured in the US Carburetion kits?


https://www.amazon.com/Anderson-Metals-Barstock-Fitting-Female/dp/B000BODVGK?th=1


----------



## FlyFisher (Jun 30, 2018)

tabora said:


> Why didn't you use a brass T like everyone else does, like what was pictured in the US Carburetion kits?


Because I wanted solid metal to drill and tap and not start with an open port. I couldn't find any "block" 90's that were NPT, only compression. In NPT just the rounded one is what I found.


----------



## iowagold (Jan 22, 2020)

the buzz word is
*Barstock Street Elbow*


----------



## tabora (Sep 6, 2018)

FlyFisher said:


> Because I wanted solid metal to drill and tap and not start with an open port.


Why? What does that accomplish?


https://www.amazon.com/Anderson-Metals-Barstock-Fitting-Female/dp/B000BODVGK?th=1


----------

