Suzuki dt2 Outboard

[seafox]

Each season I drain and replace the gear oil, clean the small fuel filter and change the spark plug in my little suzuki dt2 outboard. I use it on the back of the dingy and it only does about 10 hours a season.

Near the end of the season it seems to lose power and slowly come to a stall after a short run.

When I change the sparkplug it is always very black and wet with a black oily sort of substance.

My manual tells me very little.

Does it sound like it is running a little rich? The manual shows me how to change the idle but there is nothing in it about how to adjust the mixture. Anyone got any idea? It all looks pretty basic. I was considering starting it in a bucket and twiddling with screws on the carb until I got a result.

[seafox]

here is a link to the carb Suzuki DT 2 (1990-1997) Fig. 5 - Carburetor
Is the pillot air screw the one to twiddle with? Labelled part 24.

[CSY Man]

Too much oil in the fuel?

Some engines run on 1%, some on 2% and some on 3% mix....

[Kanani]

I loved my little Suzuki 2hp. I also had a Yamaha 8HP but I only used it to go long distances.

Your problem may be a heavy float. They often get soaked with gas (sorta like water logged) That's a constant problem on those things. I always carried a couple spares. Change the needle valve while your at it. (They used to come together with the new float, I think)

Oh ya.....always remember to drain the fuel from the carb when the outboard is going to be unused for more than a week.

I've seen people throw away their 2hp outboards. In every case, I would grab it, put a float in it and it would run like new. Then I'd sell it and add the $ to the cruising kitty.

[seafox]

Originally Posted by CSY Man

Too much oil in the fuel?

Some engines run on 1%, some on 2% and some on 3% mix....

I was wondering that. It is 100:1 though so didn't want to cut back on that.

[seafox]

Originally Posted by Kanani

I loved my little Suzuki 2hp. I also had a Yamaha 8HP but I only used it to go long distances.

Your problem may be a heavy float. They often get soaked with gas (sorta like water logged) That's a constant problem on those things. I always carried a couple spares. Change the needle valve while your at it. (They used to come together with the new float, I think)

Oh ya.....always remember to drain the fuel from the carb when the outboard is going to be unused for more than a week.

I've seen people throw away their 2hp outboards. In every case, I would grab it, put a float in it and it would run like new. Then I'd sell it and add the $ to the cruising kitty.

Thanks, on the carb, what does the pilot air screw do?

[Kanani]

Originally Posted by seafox

Thanks, on the carb, what does the pilot air screw do?

The pilot air screw adjusts the amount of air that is introduced to the venturi at idle only.

To adjust it, slowely turn it in until the engine stumbles, then turn it back out until it stumbles again. Then turn it back in, just far enough for it to run smooth.

[seafox]

Thanks,
are there any adjustments that can be made to the mix/air when running (not idle)?

[Kanani]

Originally Posted by seafox

Thanks,
are there any adjustments that can be made to the mix/air when running (not idle)?

Not really. In order to change the air/fuel mixture once the throttle is opened (on a properly running engine), you would have to change the size of the main jet. I don't recommend doing that. I think that your problem is either oil/gas mixture or float related. If you were running too lean, that might be all kinds of things, mainly to do with vacuum leaks. However, what you seem to be experiencing is a rich mixture. That can only be too much fuel being introduced or too much oil in the gas.

My guess is that the float is too low in the bowl and the needle valve is being held open which will introduce too much fuel....thus, a wet spark plug. Trying to adjust the float may work temporarily but I would still suggest replacing it. They only last a couple years before they start absorbing gas, in my experience.

[seafox]

thanks,

just pulled the float housing off and cleaned a whole lot of rust out of it. The float is just a plastic ball cock type float on my motor. It seems to float up and down freely. It does not have an petrol in it. I have cleaned what I can get to and will put it all back together and see how it goes.

Might try mixing a bit less oil. Have been using 5mls per 500ml so will drop it to 4.5mls and see how I go.

Very wet spark plug. Like used car oil in it.

[seafox]

this motor has pretty much done this since new so it must be the oil/gas mix. Thinking about it I may have been putting a ml more in each mix. Always erred on the side of too much oil rather than not enuff. Will put it on a slight oil diet and see how it goes.

Thanks for you help.

[Kanani]

Originally Posted by seafox

this motor has pretty much done this since new so it must be the oil/gas mix. Thinking about it I may have been putting a ml more in each mix. Always erred on the side of too much oil rather than not enuff. Will put it on a slight oil diet and see how it goes.

Thanks for you help.

Adding too much oil will not add life to the engine. It will only cause grief. Empty and clean the tank and carb bowl. Install a new spark plug. Mix your oil very accurately. I mean, be anal about it. (I think that engine is 100:1, isn't it?) The engine is designed to run on exactly the advertized ratio. Deviating the slightest bit will make a difference in performance and life.

That "Plastic" float is actually poured into a mold. It is solid foam, when you cut it in half. It will absorb gas. If it floats in gas without sinking (even a little) it may be OK.

If you got rust out of the bowl, that means that it had water in it. It's best to drain that carb out once a week in wet climates. there should be a drain screw in the bottom of the bowl.

[seafox]

I usually use a medicine measure cup. Will make sure it is dead on 5mls from now on. Yes 100:1
Let you know how we go.
cheers

[Boracay]

Your Suzuki dt2 should have a 1.2 litre tank.

To get 100:1 I would have expected 120ml of oil.

5ml of oil will need to be added to 500ml (0.5 litre) of petrol to give a 100:1 mix.

[seafox]

Yeah I know. We only go away for a week at a time. I used to mix 5 Litres of fuel in a container and ended up with 4l left at the end of the trip. My lawnmower was getting sick of getting fed 2 Stroke instead of straight petrol. Now I just mix 500 ml at a time. Seems to leave me enuff to wash the motor in fresh water when I get home. I just run it till it is empty and then mix a fresh batch next trip.