Suzuki 3.5 not running on internal tank

[Sandibar]

Hello forumites,

I have a 80s Suzuki 3.5hp two stroke for our dinghy. It starts and runs fine from an external tank, but refuses to start using the internal tank, which I would prefer to use. The only thing between the fuel pump and tank are a couple of short hoses and this cock valve with a net.


Can't imagine anything else besides this valve being clogged. I've opened it up without removing it from the motor and it looks to be fine inside, but then again it's a pretty small part. Is there some kind of solvent one can use to clear it, or a mechanical process? Is there some magic priming sequence for the internal tank that I've missed? Or am I on the wrong track totally?

Any insights into the workings of small outboards appreciated!

Markus

[rognvald]

S,
You have a restriction that could be caused by 1.) an inability to prime or 2.) a clogged net (#15). Try 1.) manual operation of valve, 2.)tightness of clamps, 3.)distortion or improper positioning of gasket (16), 4.) replace net (#15) and finally, check all hoses for potential leaks/crimping. Finally, is there a secondary valve elsewhere on the engine for your tank? Good luck and safe sailing. My guess is that you probably have a clogged net(#15).

[Sandibar]

Thanks Rognvald! Will take out the net and check if I get a flow. Have I understood correctly that the fuel pump is primed by gravity when using the internal tank when the cock valve is opened. There are no bulbs etc. inside or outside the motor, that I can see (then again I just noticed the damn lever of the cock valve yesterday after trying to figure out the starting problem, so I wouldn't be surprised if I missed something else as well).

[TacomaSailor]

Been There - Done That! Fixed the same problem on my 1993 Suzuki. Here is a link to boats.net who will quickly send you the required parts.

1982 DT3.5LZ Suzuki Marine Outboard Fuel Pump Diagram and Parts

Buy the Fuel Petcock (part 23-2) and all associated parts 18 - 23

I tried to repair and rebuild my petcock BEFORE I ordered the new one. None of my repair attempts were particularly useful. Once I replaced the hoses, filters, petcock I had a good fuel supply to the fuel pump.

The boats.net website has parts for Suzukis going back to 1978. There are very good to deal with and prompt in their shipments.

[Sandibar]

TacomaSailor thanks! Good to hear I'm not the only one with issues. Will try to take the valve apart and clean it first and if that doesn't work, will buy a replacement. Not sure if Boats.net sends to the EU, but I'm sure I can find the parts here.

[rognvald]

Originally Posted by Sandibar

Thanks Rognvald! Will take out the net and check if I get a flow. Have I understood correctly that the fuel pump is primed by gravity when using the internal tank when the cock valve is opened. There are no bulbs etc. inside or outside the motor, that I can see (then again I just noticed the damn lever of the cock valve yesterday after trying to figure out the starting problem, so I wouldn't be surprised if I missed something else as well).

Yes, gravity feed since there is no priming mechanism/pump for the internal tank. Before you spend any money, you should be able to run the engine by removing the filter/net. Again, be certain all your clamps are tight and that there is no restriction in the fuel lines. Good luck and safe sailing. P.S. Are you absolutely certain that you have the diverter valve for the internal tank open rather than closed?

[Sandibar]

Rognvald, will play around with the engine this weekend and see if I can make it run without the filter. I tried the lever in different positions, but did not spend much time yet on the whole thing. Pretty confident the problem is isolated to the valve now and if I can't fix it, I'll get a replacement. No hurry either, don't need the motor before May. Thanks again guys!

[rognvald]

Originally Posted by Sandibar

Rognvald, will play around with the engine this weekend and see if I can make it run without the filter. I tried the lever in different positions, but did not spend much time yet on the whole thing. Pretty confident the problem is isolated to the valve now and if I can't fix it, I'll get a replacement. No hurry either, don't need the motor before May. Thanks again guys!

Sandibar,
Disconnect the fuel line before it goes into the carburetor. Remove the filter/net. Put some fuel in the tank and open/close the valve. If fuel does not flow in either position, there is a restriction in the line or the valve is defective. Keep us posted. Good luck, Rognvald

[MARINE ENGINNER]

Originally Posted by Sandibar

Hello forumites,

I have a 80s Suzuki 3.5hp two stroke for our dinghy. It starts and runs fine from an external tank, but refuses to start using the internal tank, which I would prefer to use. The only thing between the fuel pump and tank are a couple of short hoses and this cock valve with a net.


Can't imagine anything else besides this valve being clogged. I've opened it up without removing it from the motor and it looks to be fine inside, but then again it's a pretty small part. Is there some kind of solvent one can use to clear it, or a mechanical process? Is there some magic priming sequence for the internal tank that I've missed? Or am I on the wrong track totally?

Any insights into the workings of small outboards appreciated!

Markus

internal tanks have an internal filter , is it clean?

M.E

[Sandibar]

Hmmm... Besides the cock valve assy with a net I cant see a filter. The valve assy seems clean but will properly disassemble it to check soon.

[Sandibar]

Ok, took a while, but I finally got the valve assembly out of the engine today. The problem was that the lever was not turning the actual valve inside. It had probably jumped the grooves on the valve. I suppose the valve itself was stuck after not being used for a long time. Here are a couple of pictures, maybe they are helpful to someone:


The small screw on the top locks the lever in its place together with the spring.


You can see the groove in the valve above. The lever has teeth that fit the groove.

Many thanks Rognvald, ME and TacomaSailor!

Edit: I did not run the engine yet, but there is a clean flow through the valve and it can be open or closed easily with the lever now.

[Sandibar]

If anyone's still following this: The engine runs fine now with the internal tank. Did the first test runs with it last weekend while anchored in the Archipelago. Thanks again for the help!