bensidus197217

I have a K+B outboard motor that I am having trouble getting it to run. What I have noticed is the fuel drains back to the tank and creates an air gap unless I hold the tank above the motor. When I hold it above the motor I can get the motor to flash but only for a brief burst. Another problem is I made up a drive for my starter with a socket that fits the nut on top and I believe it possbly holds on too long for the motor to catch and run freely. The reason I made the starter fit the nut was for better grip and less downward force on the flywheel therefor less wear on starting. Any help will be welcome. Thanks Jim

Dan S

the fuel tank should be lower than the carb, check to make sure it is not picking up air somewhere from the tank, the lines or from the pressure nipple on your exhaust.

Make sure you are starting the motor in the proper direction.

Dan.

bensidus197217

Actually the air is coming from the motor not the tank, it is solid fuel from the tank forward in the line and it ends at the level the fuel in the tank sits. Do you think the air could be coming from around the needle valve because the brass fitting it sits in is split so that when you tighten the packing nut the brass fitting can squeeze tight on the needle valve to stop it from turning. Is there some sort of packing or special grease you can put into the packing nut to seal it or do you think I just have my needle setting open too far. Is there such a thing as check valves for these fuel lines. Thanks Jim

piper_chuck

My Feedback: (12)

The fuel tank in most outboards is below the engine. When the engine is not running, the fuel will flow back into the tank. This isn't a problem and no back check valve is needed. When you apply the starter to the engine the combination of the vacuum from the carb and the pressure from the exhaust line (you do have one of these running from the muffler to the tank, right?) will cause the fuel to flow into the carb. It would be good to know which engine, and carb, you have. Different carbs require different needle settings. Some may need to have the high speed needle open as many as 5 turns as a starting point. I personally would ditch the special fitting that connects to the flywheel nut and go back to the rubber cone that fits the flywheel. Once the engine is spinning, it would be hard to disengage the starter from the nut, and this may be causing part of the trouble. If you're worried about applying too much downward force on the engine, and possibly damaging the boat transom, build something on the stand that supports the cavitation plate. I don't have any pics showing this, I'd have to take one when I got home.

topfuel4430

I agree with what most have said. Ditch the starter nut adapter. It works in theory, but not in reality. The normal starting cone and flywheel method works just fine. If you have a tight engine, use 24 volts or loosen the glow plug slightly until it starts. You arent goin to wear out aything using this starting method.

As Dan said, make sure you are starting it in the correct direction. Outboards turn the opposite direction from inboards.

With the throttle open, and the tank hooked up properly, you should be able to put your finger over the carb for a second or two while spinning the motor over to pump fuel into the line. This should get you ready for it to start. It depends on what engine and carb you have as far as the needle settings, but based on what you said about the "split brass piece" that holds the needle, I will assume you are talking about a 3.5cc and a black or gold carb. If this is true, the needle is likely not leaking. They are a very good design and I have never seen a leaking problem from the needle/housing itself. I would start it at about 4 - 4.5 turns out from seated. These carbs (if its what im thinking) dont have a low speed adjustment, so you are good on that.

More info and you should be able to get more help.

~James

bensidus197217

The engine and carb you described are correct it is a 3.5 with a black and brass fittings carb. I find that if I set the mixture screw more than two turns the fuel just wants to drain back to the tank. I filled the tank and pushed fuel thru by blowing on the breather pipe or pressure side pipe from the exaust and no air comes with it. I had an air boat with a prop that if I didn't have the fuel level above the carb to start with, that I couldn't get it running either. The needle was bent at one time not badly but enough to be obvious, so I straightened it as best as the eye can see and I am wondering could this bend be causing me problems or is the bend such that I may be able to only turn it in two turns til it bottoms and the setting may be greater than I think. I wasn't gentle in turning it in but not forceful enough to damage, could the valve seat be damaged it's too small to see if any has happened maybe I need to get out the magnifing glass. Thanks and I hope this gives a little more info. Jim

topfuel4430

Was the taper portion of the needle bent? Or the part that sticks out of the carb? If its the tapered portion, you may have a problem. If its the outside portion, dont worry about it. I have plenty of needles I can send you if you need one. Just would need your address.

You should be able to loosen that locknut on the needle, and turn it in very freely until it seats. it will be obvious unless there is a problem.

I can tell you, if the needle is working like it should, 2 turns out is MUCH too lean. I realize the fuel may go back into the tank if you go ridher, but it should have no effect how the engine runs. Have you tried the finger over the carb thing? It should certainly pump fuel in to the motor when you do that. Once you get fuel in the engine, remove your finger and it should pop off. Once its running, the pressure from the exhaust and vacuum from the draw of the carb will keep the fuel coming.

~James

piper_chuck

My Feedback: (12)

Once again, don't worry that the fuel flows back into the tank when the engine is not running. This is completely normal. If you have exhaust pressure hooked up, that plus the vacuum from the carb will get the fuel through the line. And as James said, 2 turns is nowhere near enough open.

Here's a very simple test to see if the needle can be screwed in all the way. Attach a clean piece of fuel tubing to the carb. Blow into the fuel tubing while closing the needle. If it gets harder and harder to blow, until it's impossible when the needle is all the way in then it is going in all the way. If it's still quite easy to blow through the fuel line then the needle may not be going in all the way.