Unburned Fuel collection

[bill-mcnamara]

Last weekend I had the twin Javelins out for a Sunday Cruise an a beautiful day.
I have rigged up hoses from the case drain covers to these bottles, and blocked the exit into the exhaust stream.
A sturdier collection container, possibly vented overboard will follow.

The run was about 1.5h total running time, with a good combination of conditions,
about 50% slow speed "putting" and the rest at higher RPM. Motors were running very smoothly, starting and stopping at friends docks etc.
Fuel consumption for the day was about 2.5 gal each.

I was a bit surprised by the volume collected, about 16 oz for each engine.
The captured fuel was nice and clear, and looked very re-usable.
Next run, I will try to keep the RPM’s up a little more, and see how that effects the collection efforts.

It felt really nice NOT to leave a rainbow sheen when stopping at other peoples docks, and for not spitting fuel into our crystal clear lake.

I’m wondering if any of you "fuel collectors" in The Club have had similar experiences with Big Twins?

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[wbeaton]

I did the same thing back when I ran a 1956 Javelin on my Feather Craft. It was staggering how much it collected. I just dumped the unburnt fuel back into the tank. There were never any issues. I also did the modification on two 1961 40 hp Johnson’s that I’m putting on a cabin cruiser. I wouldn’t have a Big Twin/RD without the modification. It saves the environment and increases fuel economy. How can you beat that?

I have one question about your set up, which is beautiful by the way. Can you tilt just one motor up at a time with your steering bar like that? I’m still figuring out how to set up my twins. I’m using Teleflex so it will be a little different.

Wayne
Upper Canada Chapter

uccaomci.com

[RICHARD A. WHITE]

I am not exactly sure where you are referring to when you mention case drain covers?

Here is a thought.. Get one of those 3 gallon Mercury tanks and dump those lines into it instead of the bottles. you can then reclaim it all since it is not under pressure it will just go right in, then with a simple rattle siphon hose you can just transfer the fuel back into the pressure tanks when full.. Can also be considered your emergency spare fuel…

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[amuller]

I’m getting ready to start running a ’72 V4 85 hp, and have been thinking about this crankcase drain business. This motor uses one carb bore per cylinder and I presume the crankcase is divided accordingly. Are there CC drains, and, if so, how do I divert them into a container?

Thanks.

[opposedtwin]

Bill, can you show us the other end of those bottles? What are you hooking the tubes up to on the motor?

[jim-moffatt]

The big twins have two crankcase drain reeds feeding into a single drain cover. Drill a hole i n the cover and add a small hose fitting. Then block the outlet to the motor leg. I have been doing this on my 55 Big Twin for over 10 years. I collect about what is stated above. My collection container is an old steel gs can with a hose put in the lid. but it needs a vent to collect well. I recycle the collected fuel to my fuel tank. But it can also be simply disposed of.

[chris-p]

I too have done this on many motors for many people.

I took pictures on a 40hp powerhead I just rebuilt.

Pictures show the cover that you tap and install a barb on, the drain hole you plug up, and the routing that excess fuel/oil mixture normally makes into the mixture of spent cooling water and then into the lake.

I don’t get a ton at WOT< but at idle the 35/40hp motors dump quite a bit out of them.

I installed a fuel pump on a couple different motors, but kept the 2 line system. The old AIR line I transformed into the new FUEL RETURN line from the barb. I then drilled/tapped a vent system onto the pressure tank. From initial glance, appears completely bone stock. Unless you look closely!

[chris-p]

Oops forgot pictures.

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[chris-p]

ALso, in my last picture, you can see how badly plugged the screens normally are. Very few mechanics take this apart to clean during a tune up. This should be done every few years or it will start to affect your idle with the puddling fuel/oil mixture that cannot properly drain.

[ryanjames170]

So if I might ask a dumb one how dose the oil gas mix get into these drains? Ie with out creating a rather large pressure leak in the crank case?

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