New LEHR 9.9 propane outboard tip

The next generation of boater! Good.

HopCar said:

I was planning to put a Lehr 9.9 on and I was just going to just turn my regular propane tank upside down to supply liquid to the engine. Anode your comments about the relief valve have me rethinking this. Anode you understand the application, could an upside down tank be a problem for me?

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Back on topic ...

I am not a "propane expert" but the reason the propane people say the relief valve should be above the liquid level is that in the extremely unlikely event that pressure in the tank increases to the point that it opens (which will be the same pressure no matter what is covering it) it will vent gas.

If it vents liquid, the amount of flammable gas will be nearly 270 times the volume than if it were just gas. If the tank got hot enough to vent because your boat is on fire, it could be a problem.

If that scenario is a big concern, get one of the horizontal tanks with a liquid take-off. Forklift tanks might be the best option.

Rick, I think fire on a small open boat is pretty unlikely but the tank will be sitting in the sun. I wonder if that could raise the pressure enough to open the valve? Forklift tanks are bigger than what I was hoping to use but might be a good option.

On a gasoline engine liquid fuel comes from the tank and gets vaporized in the engine. On a propane engine liquid propane comes from the tank and gets vaporized by the vaporizer/evaporator. Then only the vaporized propane goes to the engine.

A full P tank weighs a lot. Empty tanks weigh little. Where does the liquid propane go? To the vaporizer and then (as vapor) into the engine via the throttle valve. The vaporizer dosn't pass liquid propane.

That's why propane engines run perfect when cold. The fuel is already vaporized when it gets to the engine.

I believe tanks are designed to pass only liquid propane and need to be oriented to do that. I don't think the air in the P tank is vaporized propane ... probably just stinky air.

Not going to court w any of the above but I think that's basically the way it is.

Hop Car your boat looks great. I'm still think'in of building this;
http://www.spirainternational.com/hp_keyl.php

Hi Eric, That looks like a fun project. I see boats like that used to catch mullet on the west coast of Florida. I'll need to spend more time on that website. They have some nice designs.

Some tanks are designed to supply liquid propane others vapor. It just depends on where the pickup tube is. If it's at the top of the tank you get vapor, at the bottom you get liquid. The typical 20 pound barbeque tank will supply propane gas unless you turn it upside down. Then it will supply liquid propane. Rick and Anode have pointed out the safety issues with turning the tank up side down.

HopCar said:

Rick, I think fire on a small open boat is pretty unlikely but the tank will be sitting in the sun. I wonder if that could raise the pressure enough to open the valve?

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The tank will have to get close to140F to open the relief. How likely is that?

Look around, I think they make liquid withdrawal valves that fit #20 bottles ... not positive though.

I think it is much ado about nothing really.

HopCar said:

Rick, I think fire on a small open boat is pretty unlikely but the tank will be sitting in the sun. I wonder if that could raise the pressure enough to open the valve? Forklift tanks are bigger than what I was hoping to use but might be a good option.

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Rick has the correct solution.
If you turn a barbeque tank upside down the safety relief valve is in the liquid and non-functional as designed. A tank in the Miami sun has the potential to rupture rather than vent the excess pressure if the safety valve is compromised.
Most forklift tanks weigh around 55# full (tank and propane). They do make smaller horizontal liquid tanks for floor polishers etc.
Check the Worthington site. Worthington Cylinders - Products
Remember that liquid propane boils around -42F. Wear the proper PPE when handling.

Minimum burst pressure for a #20 tank is 960psig. Do the math in the hot Miami Sun.

This is getting complicated. I think I'll just run the engine on vapor. The Worthington tank site says that liquid feed tanks have different threads than vapor feed tanks.

HopCar said:

This is getting complicated. I think I'll just run the engine on vapor. The Worthington tank site says that liquid feed tanks have different threads than vapor feed tanks.

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No biggie:

OPD ACME Filling Adapter

And this:

Forklift Coupler Attachment

In post 13 of this thread, Tom brought up a problem he had with his 5.0 Lehr running slow.
I sent an email to the engineer at Lehr who has answered questions for me in the past. Following is a copy of that conversation. I think Rick gets the prize for first right answer. The engineer's answer is in red.

"On one of the forums on the internet, there was a discussion about a Lehr engine that would not maintain full speed after running at WOT for a period of time.
It was a 5.0 running on a small can. Weather was cool and humid. Do you think the little propane can was just getting too cold and the propane wouldn’t come out fast enough?Yes Another theory was that ice formed in the carb.No What do you think?After the small tank is half full, the evaporation is happening in the tank, not the carb or evaporator. The aluminum bottle tray is meant to feed heat to the bottom of the tank to help it evaporate at the necessary rate. But long WOT and cool weather combined it is possible to see this condition on the last little bit of propane in the tank.

I know the 9.9 has a propane vaporizer but what vaporizes the propane on the smaller engines if they are fed liquid propane? 5 hp has evaporator also. But that only takes care of it when liquid is being fed into the system during 1st half of the tank. (small 1lb. tank)
The 2.5 evaporation rate is slow enough even at WOT that an evaporator is not necessary."

Speaking of propane tanks, have you guys seen this?

PHMSA - Home - PHMSA Orders Recall of Cylinders Manufactured by The Lite Cylinder Company

Those are not used by most cruisers as you have to take your tank and wait till it gets filled , while a taxi awaits.

UGH!!

A $17 swop at 7/11 or a gas station works loads easier.

There has been a lot of talk about it over on the Cruisers Forum where a lot of the long range cruising sailboat guys use them. They like that they are light and don't rust. Unfortunately the company was forced out of business by the recall and there is no where to return the tanks.

Trident Marine, the hose guys, sell a different brand of fiberglass tank but they are sold out. I have one of Tridents 11 pound tanks to use with my Lehr outboard. It's really nice. It's light and it doesn't leave rust rings where ever I set it down.

Hopcar,

Thanks for the info from Lehr. When it happened I was pretty sure it was not mechanical, just an operational issue unique to running at WOT with a small tank on a cool day. At WOT a 1 lb bottle quickly gets out of the liquid into the vapor. I also have one of the Trident 11 lb tanks, but hold that in reserve for the Honda EU2000 generator I have converted to propane. The 1 lb bottles are just too convenient for most of my dinghy adventures.

tpbrady, how long can you run the 5.0 at WOT on the 1 pound cylinders?
The specs say about 1/2 hour. Is that true in the real world?

I would say that was in the ball park, however where I live I think true WOT could only be sustained for 5 minutes and then things would slow down as the bottle cooled off and couldn't meet the propane demand. If I find a nice warm sunny day I may run WOT and time it.

Tom

Bump...

It's been 3 years now that our Lehr 9.9hp propane 'get home' kicker has been sitting on our swimstep, and it's never once seen duty because of a main engine failure...only getting fired up once in a while to make sure it still works.

So it's gone through 3 north coast BC winters without ever being winterized, and this spring the first "issue" turned up; the flow from the cooling water line started strong, sputtered, then stopped.

I brought it home, put it on a stand, pulled the last section of hose (thinking I might get lucky and clear some obstruction without taking the leg off) and it worked. Whew!

The neatest part of the whole exercise was that I took a propane tank off our trailer which hasn't been used in 7 years, and the Lehr started on the second pull. The tank was probably filled 8 or 9 years ago.

Propane doesn't go bad or gum up the carb. That is exactly why my emergency generator only runs on propane. I've started my generator once a year for more than ten years and it's never failed to start.

I bought a Lehr 15 about a year ago for a little skiff I built. It has a small battery under the cover and an electric starter. I love it.

Tip 7: Wait until they work the kinks out before buying one.

How do folks secure a propane tank in a dinghy?

dhays said:

How do folks secure a propane tank in a dinghy?

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The most sensible way based on what kind of dinghy you have?

We'll soon be getting a 5hp for our dinghy, which is pretty small, but it beats using oars. We opted for the 5hp because it can either use a tank, or those small canisters used for camping stoves. Somewhere in my website storage folders there's a device for refilling those canisters yourself from a larger tank...then you'd only have to bring several of those on the dinghy instead.

I carry a thirty pound forklift tank in my skiff. It lays on its side just behind the center seat. I run a couple of straps around the tank and seat.

I also have a 2.5 that I use on an inflatable. I run it from an 11 pound tank that I just sit on the inflatable dinghy deck. I carry a 1 pound can as a reserve supply for the 2.5. It stays strapped into the holder on the engine but not hooked up.

HopCar said:

I carry a thirty pound forklift tank in my skiff. It lays on its side just behind the center seat. I run a couple of straps around the tank and seat.

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So you can scoot on over to the Bahamas on a nice day?!!?

Real happy with my 9.9 HP Lehr. Like that the fuel doesn't go bad just sitting in the tank. Plan to give it a lot use this summer.

Ted

MurrayM said:

The most sensible way based on what kind of dinghy you have?

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Very true

MurrayM said:

We'll soon be getting a 5hp for our dinghy, which is pretty small, but it beats using oars. We opted for the 5hp because it can either use a tank, or those small canisters used for camping stoves. Somewhere in my website storage folders there's a device for refilling those canisters yourself from a larger tank...then you'd only have to bring several of those on the dinghy instead.

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I just saw that device on Amazon, about $18.00 if I recall. Looked like a great option for that 5hp.

HopCar said:

I carry a thirty pound forklift tank in my skiff. It lays on its side just behind the center seat. I run a couple of straps around the tank and seat.

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Back in college and grad school I worked a lot of warehouse jobs. A 40lb forklift tank sure feels a lot heavier that 40lbs! How tough is it to get refilled?

Dave I do have to take it to a place that fills forklift tanks. Not all propane sellers have the right connector. The good thing is that propane is usually cheaper at forklift tank fillers. My tank is fiberglass so it weighs less than the metal ones.

MurrayM said:

It's been 3 years now that our Lehr 9.9hp propane 'get home' kicker has been sitting on our swimstep, and it's never once seen duty because of a main engine failure...only getting fired up once in a while to make sure it still works.

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If I ever get another dinghy, it will be powered by a Lehr.

What is the weight of the 9.9 and 15hp models? Thanks!

Marlinmike said:

What is the weight of the 9.9 and 15hp models? Thanks!

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LEHR 9.9 hp 4-Stroke Outboard Engine | LEHR

LEHR 15 hp 4-Stroke Outboard Engine | LEHR