Water In The Gasoline?? Or Ignition Problem?

[ggray]

2000 Tohatsu M30 A4

Last year was at times hard to start, and ran poorly. Someone suggested getting a carb kit, which I installed myself (having never touched a carburetor before) and lo and behold, it ran fine! I didn't find a need to adjust any mixture settings, other than trying to duplicate the number of turns I found.

Then a month or so ago it started missing, and I found a spark plug wire about to fall out of the spark plug cap. So I replaced the coil/spark plug wires with a new one.

While it runs better, it still misses. Not quite like it did with the bad spark plug wire when it was obvious that at times one cylinder wasn't firing

This motor is on my dinghy, which doesn't get run much at times, and not for long.

So I wonder if it's:

I was sold a bad coil. Brand new Tohatsu stock, at least it appears, so I wouldn't think it's the culprit

Water in the gas as that is a possibility. I have replaced the gas mix in the tank. Do I need to drain the carb or flush any possible water, or will clean gas flush it out?

Did I need to (that is, know how to) better adjust a mixture screw after rebuilding the carburetor?

I've thought the water in the gas to be the first to make right. And it just seems to be that is the problem.

Thanks for any suggestions!

 

[Grub54891]

Sure, dump the fuel into a clear glass container. If there is water, you will see it in the bottom., drain the carb also. It's possible you may have to clean the carb again.

 

[ggray]

I have the last of the gas poured out in a clear container, so will look more carefully today, but I didn't notice anything yesterday.

I'll remove the carb and make sure it's clean.

Thanks!

 

[ggray]

The last of the gas dumped, which I would think would be where the water might be, looked pristine.

I cleaned the carb, but it didn't seem very dirty. No evidence of water.

The motor runs better, but still doesn't like to run much faster than a fast idle. Stumbles and misses if I open the throttle much.

But it never died on me, so that's improvement. Runs better, fine now while going slow.

How diligently do I need to clean the float valve seat? I swabbed it with an alcohol soaked Q-tip.

How critical to smooth running is the fuel level in the float bowl? I've wondered if an old fueling/prime bulb might be restricting the fuel flow. So I plan to replace it...it needs to be longer anyway.

 

[ggray]

I didn't notice how my computer interpreted my typo.

I wondered if an old fuel line/primer bulb might restrict the fuel flow.

 

[Grub54891]

If you didn't remove the adjustment screws, you did not get the carb clean. You must remove the jets and completely clean them out, with compressed air, and gently run a fine wire through all the passages.

 

[pvanv]

If you didn't remove the adjustment screws, you did not get the carb clean. You must remove the jets and completely clean them out, with compressed air, and gently run a fine wire through all the passages.

NO

A Proper cleaning does involve a complete disassembly, including jets and emulsion tube nozzle, followed by an overnight soak in carb dip, and then a thorough blow out with generic carb spray. Then a careful reassembly, paying attention to float height.

NEVER EVER push any kind of wire through ANY passages of a modern carb. Micro scratches can cause weirdness in the fuel mix at various flows.

 

[Grub54891]

I said gently. I have a kit that has tiny stainless rods and tiny nylon brushes for cleaning out passages. Most people don't have a good cleaning kit. Yea a good soak in carb cleaner is a good thing. Been rebuilding carbs for 52 years.

 

[ggray]

Thanks!
I will try again!
How do you adjust float height?

 

[pvanv]

Thanks!
I will try again!
How do you adjust float height?

By bending the tab on the float, just like any other adjustable float. Float should be parallel to the casting when the casting is inverted. Full info is in your Factory service manual.

 

[ggray]

Thanks; I'll take a look to see if anything looks askew next time I get my hands on the motor. However I don't have a service manual, and what I found online didn't address this.
While into it, I'll try cleaning again.

 

[pvanv]

The Factory service manual is available from any Tohatsu dealer. It is copyrighted, so not available online.