Generator comparison question

[Glenn_And_Kitty]

I'm looking at a Honda EU6500 verses a Yamaha EF6300. Any ideas as to which might be the all around wiser choice?

[So]

MEXICOWANDERER wrote:
Wanna know HOW HOT things get? With a dead stock engine, towing the cast iron exhaust manifolds glowed BRIGHT RED; enough to burn rubber a foot and a half distant.

Glowing exhaust manifolds doesn't prove anything. Load a lean gasoline engine pulling Grapevine on a 100 degree day and you'll experience similar results. Sorry... but the ONLY meaningful EGT readings are with calibrated K-probes mounted at the exhaust ports. LPG Stoichiometric is 15.5, on gasoline it's closer to 14.7. Ignition timing is critical, meaning that the static, dynamic and total advance curves are completely different between the fuels. Get it wrong and you risk losing an engine... with ANY fuel.

Among a few other LPG rigs I own, I have a pet Honda GX240 coupled to a Leece Neville 24V/140A alternator. It was built specifically to charge a rack of FLA batteries, but doubles nicely as a backwoods welder. When first built, I ran it for about 100 hours on gasoline before converting it to strictly propane. In preparation for LPG conversion the head was shaved .050" and a GX270 stamped steel head gasket installed. This combo netted approx. 11 to 1 CR. Next, I installed the vastly improved, 2nd gen ignition coil, altered the advanced curve, then screwed-in Iridium BPR7EiX spark plug. Prior to the mods on 87 pump regular at 50% load, EGT hovered consistently around 1080-1105f. After the mods, on propane and pulling the exact same load, the EGT dropped 55-65f degrees. All measurements were taken with a permanently installed k-probe (piped into the exhaust port) and fed to a Fluke 179.

MEXICOWANDERER wrote:
LPG powered engines leak lube oil a lot more than gasoline powered engine. Work around them enough and you also learn this point.

Nonsense.

In well over 40 years of wrenching, I never experienced such. So what was your 'experienced' assessment of the root cause?

My hands-on LPG began in 1973 at Arnold Machinery in SLC, Utah under the guidance of a veteran Impco training instructor. My forte from that day forward with AM, was LPG installs on industrial equipment... primarily Hyster & Clark forklifts. With the 70's oil embargo, LPG business was brisk, so I started my own business doing nothing but gaseous installs on any and all privately owned vehicles. Some years later I landed in French Camp, California with training emphasis on Honda portable generators.

Not in person, but I too have had a few lengthy discussions with Mr. Miller - specifically regarding his turbo/LPG Pinto. Informative gent.

That said, I guess we'll just politely disagree.

[MEXICOWANDERER]

So wrote:

robert@honda wrote:
In addition to starting/choke issues, propane and natural gas burn hotter than gasoline. This can cause the exhaust valve and exhaust value guide to overheat and possibly fail sooner.

With all due respect, propane actually runs cooler than gasoline when properly set up and adjusted. Why?... because it contains lower BTU's. The reason valves burn on dry fuels is because of the lack of lubrication & cushioning on the valve's face & seat. The constant metal-to-metal contact of the valve face & seat, disrupts the seal and eventually causes exhaust leakage. The continued exhaust leakage eventually burns the valve, not because of direct overheating. This isn't an issue when Stellite valves & seats are used.

-kenny-

Sorry, wrong...

Having spent a few thousand hours around LPG, Imco carburetion with more test instruments than Lawrence Livermore Lab, I can tell you for A FACT that the finest "tuned" conversion, even those using an LPG only carburetor run WAY the hell and gone hotter than a gasoline comparing exactly the same horsepower developed. I got SUCKED into the LPG gig by having to be around generators and then waiting and waiting for so-called LPG engine techs to waste enough of my time waiting that I had to shoo them away and get things to the point where I could go to work on the electricals.

Here is how I prepared a GASOLINE motor fuel pickup truck engine to NOT OVERHEAT while using propane. The vehicle used an IMCO 425 carburetor...

Fuel Injection cylinder heads, with the largest valves that wouldn't touch. Big ports. LPG robs room that air normally takes up. An Edelbrock Tarantula intake manifold with huge runners. Venolia 12.5 to 1 pistons - that is A LOT of compression ratio. Bruce Crower cut a roller camshaft for me with near .600" lift and short duration. Then hardened valve seats, exhaust AND intake. Titanium valves to take the heat. Wanna know HOW HOT things get? With a dead stock engine, towing the cast iron exhaust manifolds glowed BRIGHT RED; enough to burn rubber a foot and a half distant.

Why all the uproar over LPG? At the time Mexico had almost-gasoline that would screw up an engine in no-time-at-all (or even sooner). Then, BUTANE was inexpensive and clean.

With all that expense (the engine was 100% blueprinted) it ended up having very near THE SAME horsepower as a stock Chevrolet V-8 with quadrajet carburetor. Before, unloaded the truck got 15 mpg, after the LPG conversion 11.5 mpg.

But it did NOT heat up. Yeah, I even let "The Over The Hill Gang" with Carroll Shelby and Ak Miller, have a stab at it. The improvement may have been marginal if anything. These guys were the best in the LPG engine business.

ONAN after ONAN (4cyl water cooled 12.5KW) I had to tell the owners to back off their KW expectations or suffer a melted engine. One LPG only VOGUE motorhome I troubleshot ****** me off, with overheating. So I ordered up a radiator 16" taller than the original, increased the fin count per inch from 12 to 17, tripled the tube count (it was a SIX ROW radiator), and I managed to keep the temperature under control. You'd better know what you are doing with LPG or you are going to be in for A LOT of surprises. LPG powered engines leak lube oil a lot more than gasoline powered engine. Work around them enough and you also learn this point.

[doughere]

I'd base it on which you can locally get good parts and service from.

Doug

[robert3]

So wrote:
The reason valves burn on dry fuels is because of the lack of lubrication & cushioning on the valve's face & seat. The constant metal-to-metal contact of the valve face & seat, disrupts the seal and eventually causes exhaust leakage. The continued exhaust leakage eventually burns the valve, not because of direct overheating. This isn't an issue when Stellite valves & seats are used.

-kenny-

Thanks for the facts about this, Kenny. Never to old to learn.

I'll guess most folks that do convert to propane or natural gas don't bother to update the valve parts to deal with the lack of lubrication. Wonder how many hours it would typically take for a converted engine to start having problems?

-Robert@Honda
Caveat: I work for Honda, but the preceding is my opinion alone.

[So]

robert@honda wrote:
In addition to starting/choke issues, propane and natural gas burn hotter than gasoline. This can cause the exhaust valve and exhaust value guide to overheat and possibly fail sooner.

With all due respect, propane actually runs cooler than gasoline when properly set up and adjusted. Why?... because it contains lower BTU's. The reason valves burn on dry fuels is because of the lack of lubrication & cushioning on the valve's face & seat. The constant metal-to-metal contact of the valve face & seat, disrupts the seal and eventually causes exhaust leakage. The continued exhaust leakage eventually burns the valve, not because of direct overheating. This isn't an issue when Stellite valves & seats are used.

-kenny-

[Dan_69GTX]

Last year I bought the EU6500is. That was after a LOT of research!! There are a lot of differences between the two of them.

I recommend you look at the web sites for both manufactures and compare notes. I know you already have a list of what is and isn't important to you so see what matches up.

Differences I know of:

Honda: easy to get parts for,
owners manuals online - free,
service manuals online or ebay (yes, they have their own ebay account),
GREAT resell value since they are more popular.
Quieter.
Why did they have to put the fuel filler cap in the middle of the fuel tank - makes it a pain to refuel.
Higher Max wattage.
Can run for up to 30 min above rated load (and of course below max load).
Has a pull start in case the battery is dead.
Honda is willing to allow an employee to post and answer questions - does Yamaha do that?


Yamaha: similar to Honda,
called MFG and they will not say how long you can run above rated, but below max, wattage.
Parts and owners manual online - free, service manual online.
Not sure how hard to refuel.

I am VERY pleased with my Honda.

[SaltiDawg]

robert@honda wrote:

...
Caveat: In the USA, converting a portable gasoline generator to run on propane or natural gas, etc. without having it re-certified by the EPA violates the Clean Air Act. ...

-Robert@Honda
Caveat: I work for Honda, but the preceding is my opinion alone.

So conversion from exclusively gasoline to exclusively propane, as I have done, puts one in the interesting position of likely polluting the air much less than gasoline but not having the paperwork to "permit" it. :R

Also, with a load block to adjust propane or NG flow, there is no need for the engine to operate hotter.

[robert3]

There is an extensive thread about converting an EU6500is to tri-fuel operation at this link:

Honda EU6500IS with tri-fuel conversion

In addition to starting/choke issues, propane and natural gas burn hotter than gasoline. This can cause the exhaust valve and exhaust value guide to overheat and possibly fail sooner. FYI, Honda used to offer a propane generator, and used higher heat-tolerant materials for these parts.

Caveat: In the USA, converting a portable gasoline generator to run on propane or natural gas, etc. without having it re-certified by the EPA violates the Clean Air Act. Honda does not support any conversions, and any damage or failure of the generator caused by such a conversion is usually not covered under the Honda factory warranty.

-Robert@Honda
Caveat: I work for Honda, but the preceding is my opinion alone.

[Glenn_And_Kitty]

smkettner wrote:
What is the expected use? Any specific concerns?

I'm going to use it for TT and a few things in my home if I have a total outage. My plan would be to stay in TT, which I can park next to my house, and run fridge, freezer, and perhaps few other things in the house while fully powering the TT. Both models of the Honda and Yamaha have 220 outlets so I can use my water well when needed. That’s why I'm opting for the 6000 plus models.

I read where the Honda, after conversion to propane or natural gas, has some issues and a regular carburetor adjustment is necessary depending on air temp. I think it has something to do with the automatic choke system not being needed when running on propane.

[TXiceman]

It is a toss up...both will give you excellent service.

I have had a pair of Honda EU2000i for 3 years and never a problem. Reminds me I need to get them out and run them.

Ken

[time2roll]

What is the expected use? Any specific concerns?

[Wayne_Dohnal]

Here's one source for a propane conversion for the Honda http://www.generatorsales.com/order/Honda-EU6500iSA-Tri-Fuel-Kit.asp?page=Honda_EU6500iSA_Tri_Fuel_K... .

I run my eu2000i from propane and gasoline. It works, I do have to fiddle the propane mixture adjustment some for light vs. heavy loads.

[MrWizard]

is either one water/liquid cooled
it will be quietest one.

[Glenn_And_Kitty]

Original poster: Thanks for the input so far. I forgot to ask in my original post: Would anyone know if either or both can be converted to run on propane as well as gasoline?