Tohatsu 3.5 HP Outboard won't start, what is this rubber thing

[autumnbreeze27]

I am in San Carlos, Mexico. We bought this Tohatsu 3.5 HP motor new, right before we left. I recently changed the oil, gassed it up, and it won't start.

When I first put it on, it had probably been sitting for about 3 months (hot baja sun), I probably forgot to drain the gas out of it 3 months ago.

I pulled and pulled and got it running... it ran for 10 seconds, I pushed the choke in, and it died. I never got it running again, and it was dripping gas, so I'm guessing the carb is the problem.

So I take the carb off, take it to a buddies place, and he tells me this little rubber cap comes bouncing out of it when he takes the float bowl off. We look up the diagram online, we think we got it in the right place, has anybody seen this? You can see the rubber plug in the pic, it's installed where we think it goes on the right side in the pic.

So after cleaning all the jets, etc with carb cleaner (in aeresol can), I tried it yesterday and when pulling it almost started once, but still no love.

Any tips? Can you tell if I got that stupid rubber thing in the right place? I'm hoping I can find a can of that stuff u dip the carbs in here in an auto parts store.

[jamhass]

I had the same engine, and as I recall the rubber plug (as shown on your picture) goes to the lower left of the main jet. ... but I am not 100% sure ...

The idle circuit on that carb is a PITA to clean. I found a can of carb cleaner with the little straw works well. Spray the little tiny holes, wait a few minutes, spray again repeat, repeat .... until you get flow out of the holes near the throttle plate. It does take patience -- and do NOT try to clean with a wire!!!

[bvander]

These carbs are poorly designed.
Here is what i do
Strip carb completely
Blow out all channels with carb cleaner
Should have 2 jets, idle and run, run is under brass screw with hole, idle beside it, which is where that cap goes if there is no solid screw.
To ckean idle jet need a thin piece of copper wire and use that to poke all the little holes as well as through the center.
Also make sure the small hole/channal between where run jet is seated to the seat for idle jet is also clear. Thin wire bent 90 degree can help if carb cleaner jet doesnt work
Also make sure seat for float valve is clean, carb cleaner with q tip works well.
Reassemble, being careful with gaskets.

[kmacdonald]

Soak it in carb cleaner overnight and then blow it out with compressed air.

You can also buy a new carb fairly reasonable.

[fryewe]

Yep. If you let that engine and carb sit for a couple of months with ethanol-laced fuel in it, you'll have to clean it up.

You didn't mention that you tossed the old fuel out of the tank and put fresh fuel in...making sure hoses and fuel filter are clean as well. If you didn't do that, you need to. And use non-ethanol fuel if available.

It's been a while since I had mine apart, but I think the rubber cap goes exactly where you have it.

[belizesailor]

Originally Posted by jamhass

...
The idle circuit on that carb is a PITA to clean. I found a can of carb cleaner with the little straw works well. Spray the little tiny holes, wait a few minutes, spray again repeat, repeat .... until you get flow out of the holes near the throttle plate. It does take patience -- and do NOT try to clean with a wire!!!

Carb cleaner with straw works well, but be sure and wear saftey glasses...powerful eye irritant.

[kerrydeare]

Originally Posted by autumnbreeze27

... I pulled and pulled and got it running... it ran for 10 seconds, I pushed the choke in, and it died. I never got it running again ...

I really like my Tohatsu 3.5, bought new in 2010. For reasons I cannot explain, this small beast is sometimes difficult to restart after running for a while. It often takes several different combinations of throttle, choke, and perhaps a few other adjustments to overcome the problem. BTW I am very careful to follow the long-term storage procedures when such action is required.

My current solution is to let the engine, once started, idle in neutral for several minutes, and then very gingerly shift into gear and proceed with caution, keeping one's ears tuned to any possible fade out. Once running, I find it quite smooth for a single-cylinder design. A bit heavy at 43 pounds but that's the 4-cycle price one has to pay.

[a64pilot]

Originally Posted by belizesailor

Carb cleaner with straw works well, but be sure and wear saftey glasses...powerful eye irritant.

Incredibly, powerful eye irritant,
Don't ask

[Orion Jim]

The carb is a piece of crap, it floods in a heartbeat. The only way to keep it reliable is to turn off the fuel and run the carb dry with each use....I turn the fuel on and pull start it, if it doesn't start in a few pulls it's flooded. Open the screw on the bottom and drain the carb. Try it all over again. As I approach my destination I turn off the fuel and run it dry again. I miss my old Merc two stroke that ran reliably for many years.

[autumnbreeze27]

I found another thread on another site with pics that showed I put that stupid rubber stopper in the wrong hole.

So my buddy is cleaning the carb some more and will fix it while I'm in San Diego renewing my visa and drivers license and drinking ipa

At least, that's the theory.

Why put a hole in a carb and put a rubber stopper in it?


Sent from somewhere in the Pacific