9.8 2-stroke starts right up, runs for a bit, winds up and stalls, won't restart.

[fortunate2001]

OK, have created a new problem...
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I cleaned the carb on my Tohatsu 9.8 2-stroke. Took it all apart, soaked it overnight, and reassembled. Since then, when I go to use it, it starts up first pull (with choke on for a couple seconds then off, just like it used to). Seems fine at that point. Then I?ll get underway, and in 30-60 seconds or so, it will begin to rev higher, slowly ramping up (I?m not touching the throttle), then it will stall.

At that point it won?t restart. I can pull on it all I want, nothing. On a couple occasions, I was able to get it running briefly by opening throttle full blast, and pulling several times. It will start to catch and run, and after the initial smoke-fest clears, I have to ride the throttle in the high to very high range up and down to keep it going, but even that stalls out again in a minute or two.

So, I row, and later in the day when I return (hour or two at least), she starts right up and purrs like a kitten, no stalls, no problems.

One other symptom: After trying to restart, I noticed fuel dripping out the weep hole of the engine enclosure, popped the cover and see the carb is leaking fuel when I am pulling the starter rope. This does not happen when it is running normally, only when it has stalled and I?m trying to restart.
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Could it be flooding due to a stuck float switch? Maybe I cleaned the float switch so well that is lost all lube and is binding in the open position? Or I bent it or broke it. That might explain why it starts, then after the fuel pump starts pumping, it floods the carb with gas, revs, then dies? And later, after a few hours, the float switch has come loose and is working again?

Should the bowl leak if it is overfilled? Or maybe I should replace a gasket there?

Sound familiar? Any ideas? Other theories? Questions?

As always- TY in advance.

 

[pvanv]

Sounds flooded. The bowl o-ring seldom leaks. Probably dripping from the vent at the top of the carb. Could be a sticky needle. Disassemble and re-check, or install a carb kit with new needle.

 

[pro-crastinator]

Then I?ll get underway, and in 30-60 seconds or so, it will begin to rev higher, slowly ramping up (I?m not touching the throttle), then it will stall.

Classic symptom. Ran out of fuel. My thoughts are that there is a fuel starvation problem.

When I finish cutting the grass on my 9hp snapper rider, I turn off the fuel valve and keep the engine running to empty the carb.
Near the time when it runs dry, the rpm increases (mixture leans out) just before it runs dry.

Next time its running, be prepared for the "surge" in rpm and start squeezing the fuel bulb and see if that changes anything.
Fuel pump warrants a look see.

good luck

 

[Sea Rider]

Won't need to lube anything inside carb, you're running 2 strokes oil in the mixture, check needle shape must be pointy sharp, if rounded propably is sticking inside needle seat. You could have bent float's metal actuator out of adjustment when cleaning ? Reverse carb and check that float is even with metal base, but check firstly needle cond. Install a new base 0'ring gasket just in case it's already flat or dried.

Happy Boating

 

[fortunate2001]

Thank you all for your replies.

check needle shape must be pointy sharp, if rounded propably is sticking inside needle seat. You could have bent float's metal actuator out of adjustment when cleaning ?

Sounds like a bit of consensus that the problem is in the float assembly... It all 'looked' good to me when I reassembled, straight and sharp, etc., but certainly worth a closer check. Maybe I bent something on reassembly. If I can't see anything wrong, I guess it will be time to start replacing things.

Reverse carb and check that float is even with metal base,

What do you mean by reverse the carb?

 

[Sea Rider]

Remove bowl, turn upper body up side down and check float is parallel to carb base :

float_________
_____________carb base

Check that internal needle seat is not scratched, deformed for needle to sit and close nicely.

Happy Boating

 

[isaksp00]

I think it means turn the carb upside down.

 

[MattFL]

Your symptoms when it stalls sounds like it's starving for fuel, but gas dripping from the carb sounds like the float is stuck open. Couple ideas; the carb cleaner jacked up the rubber parts and the float is sticking both open and closed. Get a new float needle (the rubber tipped part). Or, the vent on the gas tank is closed. When it runs and the tank becomes a vacuum the motor starves for fuel and dies. After sitting vapor pressure builds causing too much fuel into the carb causing the leak. Open the tank vent. These are my guesses, please let us know when you figure it out.

 

[Sea Rider]

How old is that fuel hose/engine ? Have you tried running engine with other fuel line that's working properly ? When fuel connectors o'rings gets old, dried, worn, air gets inside fuel line and gives strange fuel related issues. Down issue, both connector o'rings are not being offered as spares, will need to take fuel line to a auto shop and have both o'rings replaced with same size and diam ones.

Happy Boating

 

[rdhoagland]

Solved problem with identical symptoms this morning. After rebuilding the entire carb, including all new jets (however, without a new pilot adjustment screw), it turned out to be a bad O-ring on the fuel line!