Nobody can give me a straight answer on this one, but I'm open to all opinions. I've been told by some certified mechanics that the kicker should NOT be tied into the same fuel/water separator as the main. This is because when one engine is running, the other will suck air, thus straining the fuel pump and running the engine lean. This could end up costing you a new fuel pump or even a new engine.

The solution I was told is to use a gated valve so that the line runs from the tank --> gated valve -->then each exit line to it's OWN fuel filter-->then on to one engine.

This is a $160 modification for me... is is worth it??

Yes.

Are you running two-stoke or four-stroke for power?

For my four-stokes I have a manual shutoff for my kicker at the filter tap. I'll look for the image, and show a less expensive work around.

If your filter is in an open space, this might work for you. Just remember to shut the valve before running the main motor.

Don't know why it should cost $160, I've done it to several boats, $30 in parts for the valve and four hose clamps, 10 minutes to do the job. It is definitely worth it though, even if it cost $160. No need for a second filter, the valve goes on the engine side of the filter/fuel/water seperator and just switches from one motor to the other.

How is the other engine, the one that isn't running, "sucking air"?

Maybe I'm all wrong, but when I hooked up my kicker, I just came out of the other side of the filter. I was told that the ball on the queeze bulb would act as a one-way valve, as long as the direction arrow was pointed up. So I put the bulb near the kicker, where it would point up. No problems so far, 100 hours or so on the setup.

I suppose if there is a chance of a problem, the two valves would be the most secure way to go, but I'd hate to have to switch over every time I switch between the big engine and the kicker.

Use Petroleum Certified Check Valves in order to Keep the running engine from sucking back through the other engine... So, you have a Single fuel line running into the Filter, then when you split the line after the filter, or if you have two outlets from the filter you put a Check Valve on each line with the flow directed to each individual Motor... That way the fuel cannot be drawn back... Basically your only allowing the fuel go in 1 direction (to the motor)... I would suggest putting a 1/4 turn valve or a Gate Valve on the "IN and OUT" of the Filter Housing in order to make changing filters hassle and messy free... I would also suggest to put your priming bulb in between your tank and your Filter. Then after the valved "Filter OUT" then split your lines with the check valves and then run your lines to the engines. If you need a drawing of this let me know...

I'm setup the same as HalibutSteve:
1. 1 Gas/water separator

2. main gas line going to the "in" of the water separator.

3. 1 line, with squeeze bulb, on 1 of the "out" of the gas/water separator, going to 1 motor.

4. 1 line, with squeeze bulb, on the "other out" of the gas/water separator, going to the other motor.

Works for me........can run with the big motor, shut that off, start kicker motor and just go fishing!!!!!

I'm set up with the two lines out of the filter and primer bulb on each between the filter and motor. You'd think if it sucked air/gas out of one the bulb would flatten. I can run both at the same time and not have any problems I am aware of. Not that I do that often.

Well lots of opinions here. The thing is, you can't run a gated valve after one filter in an I/O configuration because you have to have it hard-plummed. This would only work with flexible tubing. That's why I'm looking at running 2 filters after the valve, then on to the respective engine.

As for the bulb being a 1-way check valve, in theory that's true but these valves are far from perfect and tend to leak just enough (given enough time)to drain out the line. And for my setup, the bulb to my kicker does go flat after trolling around for ~30 minutes. I've also put many hours on the standard one line to filter/2 lines out just like alot of people. No real problems yet, but this is just insurance against slapping down for a new motor.

Hey fishonjohn, where did you find parts for $30??? The valve alone is $60... are you sure you're looking at the right grade/size?

Interesting. I never thought about this. Is the problem due to boat fuel tanks not being vented?

the tanks would have to be vented. if not you would create a vacuum and then fuel starvation.

Using a primer bulbs between the filter and each motor should do the trick. If your uncomfortable with the duribility of the primer bulbs, you should be able to find a fuel compatable inline check valve. If you cant find one at the auto/marine parts retailer, try an aircraft parts supplier.

You can get away with one bulb and one filter and one switch if you put them all in series before a switch over valve. That way the bulb charges either motor and there is no chance of either motor affecting the other. Tank to filter to bulb (or bulb to filter) to switch...two lines out of switch, one to each motor. You will not be able to run both motors at the same time, however. It really is more a factor of your particular layout, but there are many options possible.

Nothing wrong with Halibut Steve's layout, either, if you're just talking about two outboards. Each check bulb will stop any feedback from one motor to the other if the bulbs are hung vertically. Any sucking action in the dead line will only seat the check ball more firmly. I wouldn't use this method with a inboard/outboard and outboard kicker combination though. The fuel in a carbureted i/o could slosh the float around and unseat the fuel check valve allowing small amounts of fuel to feed back into the kicker line. No problem at first, but after it does this a number of times then the valve becomes totally unseated due to the lack of fuel in the bowl and the kicker will suck air through the i/o's carb.

MY SETUP IS SAME AS SLAB HAPPY, 135 MERC 2 STROKE AND 8 HP HONDA//MAIN HOSE TO WATER SEP. THEN HOSE OUT TO SQUEEZE THEN HOSE TO 3 WAY VALVE SWITCH THEN LINE TO EACH MOTOR. SWITCH FROM ONE MOTOR TO THE OTHER.
WAS TOLD BY MECH FREIND THAT WITH OUT THE SWITCH VALVE YOU CAN DO MAJOR DAMAGE TO MAIN MOTOR.
ALSO HAVE TOLD OTHERS THAT WERE HAVING PROBLEMS WITH BIG MOTOR NOT RUNNING RIGHT TO SWITCH OVER TO THIS SYSTEM AND PROBLEM SOLVED.

$160 bucks wouldn't be a horrible cost. If you have a boat you should be familiar with spending money. Could save a few hundred in repairs.

Mine is setup just like slabs but my valve is betweem the two motors for easy access. I have primer balls on both motors but use the valve as insurance. Works great for me.

Twistas, I did it two boats ago on a Seasport with Volvo I/O and Yamaha 9.9 High Thrust, fuel lines do not need to be hard for I/O, flexible is OK. Last valves I bought I got for about $20 from PA Marine Supply which is now out of business but I would check with SeaMar or any other reliable discount Marine store, West Marine, Boaters World and some of the other well known stores are a little too proud of their stuff for my pocket book, if you are on the OP check out Admiral Marine Supply in Port Townsend, they cost way less for exactly the same thing. In re-reading your post I see what you are talking about by hard plumbed, just put a nipple on then attach the flexable tubing. Email me if you want and I'll be glad to take a photo of the setup I have now and email it back to you.

twistmas,

Since this is for an I/O application you might see if your fuel cell has a second tap. Go from there to another filter.
That's how my bay boat is plumbed.

Hans