Plumbing the Kicker to the Main Fuel Tank ????

[icU812]

Dad purchased a used boat from a dealer. A 2000 Smokercraft Osprey with a 50hp 2 stroke Yamaha Main and a 6 hp 2 stroke Yamaha kicker. Both plumbed to the main fuel tank. A single gasline out of the main tank to a "Y" (splitter). One to the 50 hp main and the other to the 6 hp kicker.

Situation:
First time out the Main and Kicker fire up and idle perfect. Shut off the kicker and throttle up the Main. Runs great until it is throttled down. Then it will not throttle back up. It sputters like it is not getting enough fuel. Shut it down and fire up the Kicker to get back to the boat ramp, no problem. Works great.

So the Main will not rev up at all at this point. Back home he goes.

Replace the gas, plugs and fuel filter. Same problem.

Call the dealer/marina; They have a concern that the Kicker is plumbed off the Main Engine fuel line. They claim that the Main engine will suck the fuel out of the Kicker fuel line and then start sucking air through the Kicker carb. This in turn makes the fuel to the Main lean and burns up the pistons. This also starves the fuel to the Main engine causing all the symptoms described.

Question:

Does the dealers explanation of the problem fit the symptom? Whould installing a shut off valve to the Kicker fix the problem?

On my boat the Kicker has it's own connection to the main fuel tank, no "Y". I do not have these symptoms. Is this why?

Any input would be appreciated.

[O Tshawytcha]

I ran a coustomweld where the kicker was plumbed into the fuel line. It worked fine. Unless your kicker is funky and there are no leaks it should work fine. I maybe mistaken but I thought that the fuel could only go into the fuel bowl and not get sucked back out. One way to diagnose the problem would be to try and run the main with the fuel line to the kicker unplugged. The ball valve in the kicker fuel line fitting should seal up. If the main runs fine then you know the problem is in the kicker motor. If it still doesnt run then you know that the problem is either in the main fuel line or the Main motor.
Good luck and let me know what happens!

GRIFF
PS PM me if this doesn't make sense or you want more info!

[reelfine]

If you haven't posted already, I betcha the Boat Doc' in the Boat Tech forum would know the answer for sure...

[Gundog]

icU812,
I had ths same problem with my old boat. When it hapened I would just prime the line again. It did not happen all of the time. The fittings when unplugged may suck air I am not sure they seal perfectly. I also would post the question to the boat Doc.
Mike

[Hoghunter]

I have a 225 hp and 8hp plumbed off the same fuel pickup and run both with no problem. The pickup comes out to a water seperating fuel filter and then I have two nipples off that, one to the big motor and one to the kicker. Have ran this way for years with no problem. The dealer's normally recommend that you use an anti-syphon [potty mouth] when you run the kicker off the same line as the main. However, when I did that I had problems running my kicker. I then took that [potty mouth] off and used a regular one and it's worked like a champ since.

[pnwcoast]

I do it like hoghunter. Works fine and has for several years.

[Petrel]

I have the same setup as Hoghunter, except I put a shutoff valve at each outlet of the filter. Works great.

[icU812]

THANKS evryone for the input!

Dad, are you listening???