New LEHR 9.9 propane outboard tip

A tip and a heads up to future new owners of the LEHR 9.9 propane outboards on how to bleed the air from the lines;

1) Get a paperclip,

2) Take the cowling off,

3) Find the square metal plate held by 4 screws with a small hole in the middle,

4) Attach and open the propane tank and lines,

5) Push the end of the paper clip gently into the hole...you'll hear hissing...and keep pushing until you get a whiff of propane, (I had to keep pressing for what seemed a couple minutes),

6) Give the starter cord a few pulls.

Ours started on about the third pull

**Kudos to HopCar**

Murray, thanks for posting the picture. You probably don't need to wait until you smell propane, two or three seconds of hissing seems to work for me.

I hadn't used my 2.5 in a couple of months and it didn't start after ten pulls. I did the paper clip trick and it started the next pull. I think air gets into the line if the engine sits for some period of time.

I heard from a customer today that I sold a Lehr to a couple of months ago. It gets frequent use and so far they love it. I bled the air before I shipped it and they haven't mentioned any starting issues.

Do you see the screw just above the plate? That's your idle adjustment screw.

HopCar said:

Do you see the screw just above the plate? That's your idle adjustment screw.

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Thanks for that tip too.

Here's a photo of it on its swivelling bracket;

Murray, what are we looking at? It looks like your dinghy is fastened to the swim step with Weaver Snap Davits but the engine mount is in the way. I'm guessing that you put the engine on the mount and then swivel the engine onto the swim platform. Then when the dinghy is pulled up it covers the engine.
Have I got it figured out?

HopCar said:

Murray, what are we looking at? It looks like your dinghy is fastened to the swim step with Weaver Snap Davits but the engine mount is in the way. I'm guessing that you put the engine on the mount and then swivel the engine onto the swim platform. Then when the dinghy is pulled up it covers the engine.
Have I got it figured out?

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Yup...sort of...the kicker swings up and the leg rests on the swim step when not in use.

The dinghy in the photo came with the boat and we'll oar it to shore until we can afford a hairy chested, gnarly, exposed coast, exploration worthy alternative.

There's no towing service here on BC's north coast, so the kicker is a get home / get to a safe cove option. For the time being, if our main engine ever failed in calm conditions, we'll tow the Livingston. If conditions are really bad and time is of the essence, we'll jettison the old Livingston, drop the kicker, and skedaddle out of there.

The kicker doesn't impede the weaver davits or the dinghy at all.

The new dinghy will probably get stored on the roof with some sort of support structure over the back deck so it does double duty as a rain shelter.

I understand. Very clever. How fast will the 9.9 push your boat?
I wonder if my little 2.5 Lehr would push Possum at a useful speed?
I'm sure your back is glad you're not lifting that 9.9 on and off the dinghy!

Don't know how fast yet, as the installation isn't finished yet. We tested the outboard at home before drilling the first hole (yikes!) in our boat.

Getting it on the bracket in our slip at the marina was bad enough (note the rope "just in case" in the photo) so I couldn't imagine trying to get it on a heaving dinghy whilst leaning out from the swim step.

The first hole is always the worst. When you get a chance to test the rig, I'd be interested in how it goes.

Speaking of holes ... I'd be careful not to get too enthusiastic sticking a paper clip into the diaphragm of that outboard.

"I'd be careful not to get too enthusiastic sticking a paper clip into the diaphragm of that outboard."
Good point. A gentle touch is all that's needed.

Interesting the Mfg sez that if not operated for an hour the fuel tank should be removed, unless a remote tank which can be turned off is used.

Sort of defeats much of the purpose of the propane outboard .

"Sort of defeats much of the purpose of the propane outboard ."

No, it doesn't.

I ran into one operating characteristic of a 5 hp that is probably unique to propane. After running for about 5 minutes at WOT (on step in a small dinghy), the engine slowly lost rpm like it is running out of propane and would only maintain about 1/4 throttle. It seems the rapid consumption of fuel (rapid expansion of the liquid from a 1 lb bottle resulted in icing in the carburetor or freezing up of the fuel line. The conditions were cool and humid. I haven't duplicated it yet, but the symptoms were just like carburetor icing.

Tom

tpbrady said:

I ran into one operating characteristic of a 5 hp that is probably unique to propane.

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It is possible that the boil off gas is cold enough to cause carb icing if the humidity is high but I suspect it is just a characteristic of propane.

And other liquified gases. As you use the gas, the liquid in the container boils off because the pressure in the tank is lowered. It requires heat to boil the liquid ... the fuel system is identical to a refrigeration system at that point but instead of cooling a heat exchanger the boil-off cools the tank. As the tank cools further, the pressure drops and more heat is required to keep it boiling.

The little tank is probably coated with frost that acts like an insulator and if the surrounding air is cool, at some point you will reach the point where you are limited as to the amount of gas that you can draw off the liquid in the tank.

It sounds like you found that point.

I think Rick described exactly what happened. I also bet that the small tank was half empty or less. When the bottle, which is horizontal, is more than half full, it feeds liquid propane to the engine and the engine gets plenty of propane. When the liquid drops below the valve, the canister supplies gas not liquid. This is when the super cooling of the tank could limit how much propane gets to the engine. It shouldn't happen if you are running on a bigger tank as the tank has more surface area to absorb heat from the air.

If the bottle was full, then carb ice sounds like a good explanation as well.

I suspect that when they come out with an engine bigger than the 9.9, it will need to be fed liquid propane.

If those little motors don't use a separate vaporizer to deliver gas to the carb and rely on vaporizing in the throat then I am surprised they run at all in Florida. Carb icing would be almost inevitable.

Do they use a coolant warmed vaporizer or ??

Do they use a coolant warmed vaporizer or ??

On RV setups the noisemaker is fed with a liquid line , not with vapor.

So the operating unit provides heat .

Outboards ? Perhaps thats why a remote big tank is an option.

The 9.9 has a coolant warmed vaporizer. I'm not sure about the smaller engines.

HopCar said:

The 9.9 has a coolant warmed vaporizer. I'm not sure about the smaller engines.

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Ah so ... then it is most likely not carb icing but a cold container. Even if feeding liquid, the container pressure drops drastically at high delivery rates so perhaps the feed pressure is only high enough to sustain a low power output.

A conventional propane tank will not deliver liquid to the engine. Only vapor.

Conventional propane tanks with liquid withdrawal valves will deliver liquid when upright. Other conventional tanks will deliver liquid when inverted or whatever covers the dip tube when on their side.

Conventional horizontal mounted tanks will deliver either liquid or vapor and may have a valve for each.

Conventional propane tanks like the disposable versions will deliver whatever is covering the withdrawl port.

RickB said:

Conventional propane tanks with liquid withdrawal valves will deliver liquid when upright. Other conventional tanks will deliver liquid when inverted or whatever covers the dip tube when on their side.

Conventional horizontal mounted tanks will deliver either liquid or vapor and may have a valve for each.

Conventional propane tanks like the disposable versions will deliver whatever is covering the withdrawl port.

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Now you're being Rick B.
My version of a "conventional" tank is the Blue Rhino tank for the barbeque. It is designed ONLY to deliver vapor. The safety relief valve on top should always be in vapor to function as designed.
Yes there are tanks designed for liquid and/or vapor dispensing. They are specialized tanks for a specialized purposes. They also have to be orientated so the safety relief valve is always in vapor. They typically have 'feet' or mounting brackets so that the relief valve is positioned properly.
I do not believe the the Luhr engine is designed to for a liquid propane. It may have a system to utilize coolant water to keep the VAPOR lines from frosting over in high VAPOR flow conditions but I don't think it has a true liquid to vapor vaporizer as larger propane engines do.
I'm not an expert on propane but I do work in the propane industry and am certified to (and do) rebuild and re-certify both liquid and vapor tanks.
Know what your engine is designed for. Know what your tank is designed for. Orientate the tank the way it was designed for. Keep the safety valve in the vapor as it was designed for.
Yes you can tip any tank to get liquid to come out the dip tube. Rick is correct and I stand corrected.

Anode said:

I do not believe the the Luhr engine is designed to for a liquid propane. It may have a system to utilize coolant water to keep the VAPOR lines from frosting over in high VAPOR flow conditions but I don't think it has a true liquid to vapor vaporizer as larger propane engines do.

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Sorry if it sounded like I was busting your chops, not intending to be mean.

Maybe HopCar can answer better but I see the 9.9 parts breakdown includes a coolant heated device called a "fuel line evaporator" so they must intend for some proportion of liquid to make it that far.

I wonder if anyone else will chime in from the colder regions and comment on this peculiarity of the engine.

RickB said:

Maybe HopCar can answer better but I see the 9.9 parts breakdown includes a coolant heated device called a "fuel line evaporator" so they must intend for some proportion of liquid to make it that far.

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I just looked at the 9.9 parts diagram and the "fuel line evaporator". It must installed as a preventative measure to keep liquid from the carburetor as they also show what they refer to as common "barbeque" tank hooked up to it in their web brochure. This would only deliver vapor in the real world. Tanks in rough water are going to slosh around....so dunno. I'm sure they've thought this out. Interesting to know if it would run off a properly installed 'liquid' tank.

I spoke to an engineer at Lehr about the liquid vs vapor thing a few weeks ago. He said that all of their engines were happy with either. He did mention that the 9.9 might slow down after running at WOT for extended periods but that feeding it liquid propane would avoid that. That led to my thought that when they release a 15, it will need to be fed liquid. I guess you just can't push enough vapor through the typical propane connection hose. What size is the hose? 1/4" id maybe?

I'm building a small plywood skiff that 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?

My boat keeps getting heavier so I might need to go to a 15!

HopCar said:

My boat keeps getting heavier so I might need to go to a 15!

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Stitch & glue, huh? I built one 4 years ago with my 6 year old grandson.

Walt that's beautiful! I didn't bother to tape the fillets on mine, yours are much neater. That dagger board trunk looks like a nice piece of wood working.
Mine's from Glen-L plans, their 14 foot skiff. What is yours? What does she look like under sail?
I detect some thread drift. Maybe the Mods should split this thread?

HopCar said:

Mine's from Glen-L plans, their 14 foot skiff. What is yours? What does she look like under sail?

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Mine is a Union Bay Skiff designed and kitted by a Seattle NA. (We didn't do any of the wood working ourselves, we just took the pieces out of the box and put the boat together (4 days) she is ten feet long, rows like a dream and sails poorly.

Very nice job! That must have been a really fun project to share with your grandson.
Is there going to be a next one?

HopCar said:

Very nice job! That must have been a really fun project to share with your grandson.
Is there going to be a next one?

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No more boat building but he is an avid fisherman and enjoys helming my trawler.