Two engines off one tank

[simonafloat]

Hi all

Just bought a 4hp johnson outboard to use as a backup/instead of my main mariner engine on my SIB. Rather than making up a completely different fuel line and primer bulb, I was thinking of using my existing mariner fuel line, putting a y connector in the line near the engine end and attaching a johnson fuel connector to the branch. Anyone think of any issues with doing this? Any suggestions also where I might find a suitable Y connector also..

Cheers

Simon

[jeffstevens763@g]

i did something similar in reverse one engine two tanks.
off a y piece with a quarter turn valve in to isolate one tank in your case both engines unless you rely on the connector to stop air being drawn in to be safe i would put two valves in one in each leg.
or swap out the connector on the Johnson for a mariner one and have them the same just one line then.
try Ron hale marine for parts or just eBay i did for the valve got a plastic one works a treat never had any issues

cheers

[willk]

Originally Posted by simonafloat

...Rather than making up a completely different fuel line and primer bulb...

...which would be an excellent spare fuel line and primer bulb for your primary engine?

Nope, better to have two engines and one primer bulb. What could possibly go wrong?

[jyasaki]

Depends on what kind of failure you're trying to recover from.

Aux motor is in case the main gives out. If it's a mechanical or electrical issue in the main engine, fine. The backup will get you home (slowly.)

If it's bad fuel or a problem with the fuel line towards the tank, you've now got 2 motors that won't run.

Personally, I'd go for 2 completely isolated systems, but that does take up space and costs a bit more.

As I said, it depends on what problems you're trying to avoid.

jky

[jeffstevens763@g]

Must admit I have a spare complete line with me all the time reinforced by the fact I had a bulb failure at the head on loch etive once.
Two separate systems best your Aux internal tank will last a fair while why not buy a small 12 Lt tank for the Aux

[simonafloat]

Yes, two separate lines sounding like the safest option. Do primer bulbs just fail suddenly then?

[willk]

Originally Posted by simonafloat

Do primer bulbs just fail suddenly then?

They can do. Some are better/less prone than others. If you can raise your tank/s to engine height then it's not such a concern but essentially the NRV aspect of the bulb can fail/block.

[Fenlander]

>>> Do primer bulbs just fail suddenly then?

The one on my 6mth old Suzuki fuel line just has. I always carry a spare new bulb/line assy with me in the SIB as part of the essentials bag. Just from personal experience I've found the Quicksilver line/bulb assys to be the best made.

[Bigtalljv]

I watched a guy get an 18 mile tow last weekend because he had fuel system issues. Main engine and kicker wouldn't stay running. He was assuming it was a clogged or broken filter. No commercial tow people around us. Guy fishing next to me jumped on that grenade and towed him back. I was next in line but had just gotten there and had two young boys with me so wasn't jumping at the opportunity of a 4 hour tow.

Jason

[jyasaki]

Originally Posted by Bigtalljv

I watched a guy get an 18 mile tow last weekend because he had fuel system issues.[snip] I was next in line but had just gotten there and had two young boys with me so wasn't jumping at the opportunity of a 4 hour tow.

USCG towed a friends boat from Carmel to Monterey Harbor (something like 6 or 7 miles?) They didn't play around; the tow was done at about 23 to 25 mph.

Ended up the problem was trying to use a jetski killswitch key instead of the Honda (on the same keyring for some reason.) Needless to say, this fact was kept from the CG.

jky

[jeffstevens763@g]

Non return valve fails, bulb gets holes in & go hard so no suction.

[simonafloat]

I had no idea how much of a potential failure point the bulb was. Duly noted, thanks

[Yabadabadoo]

Duly noted too, Simonafloat are you proposing to take both outboard and aux when you go out and if yes what are your storage plans for the aux..?

I took my 2.2 Yam out with me the last time I went out, sort of clumsily protected the sharp bits and lashed it down with bungees but it was a far from elegant solution. The 2.2 does have an integral fuel tank so I suppose one less problem but more in another should I find that running out, trying to decant on rolling waves doesn't sound like much fun

[simonafloat]

Originally Posted by Yabadabadoo

Duly noted too, Simonafloat are you proposing to take both outboard and aux when you go out and if yes what are your storage plans for the aux..?

I took my 2.2 Yam out with me the last time I went out, sort of clumsily protected the sharp bits and lashed it down with bungees but it was a far from elegant solution. The 2.2 does have an integral fuel tank so I suppose one less problem but more in another should I find that running out, trying to decant on rolling waves doesn't sound like much fun

The johnson I have bought doesnt have an integral tank. I am hoping there is just enough space on the aerotec transom for bith engines, even if the main engine has to be shuffled across if I need to switch to the aux. My aerotec is the 420 which has a flat transom top all the way across so should be easier. Will be a squeeze though. But we'll also be just using the johnson on its own for leisurely cruises upstream and elsewhere. Want to explore the grand western canal and they dont allow more than a certain % hp versus boat length. Cant remember the precise figure but our 15hp was way over the ratio

[Yabadabadoo]

Maybe with the 420 you'd have enough width for both to be transom mounted which would be luxury in my book :-) I think if I ever went for a more serious mounting approach it would be along the lines of Kaman http://www.rib.net/forum/showthread.php?t=60215 and this mounted aux. Other thoughts have been to make use of the bow with a sheet of ply, once in place all manner of fixings can be used, more assembly time being the compromise