Tohatsu 9.8 won't start

[RichKeyWest]

Good engine never any issues super low hours looks like new. Buddy used it and dropped it in 2 feet of water getting it out of his dinghy. Was in the water for 60 seconds. Salt awayed the whole thing, changed the oil three times, changed the carb with a new one, replaced the exciter coil, inspected all connections, used plenty of corrosion x.

Started and ran great. Started it every day for 2 weeks. It sat for a month now won't start.

Checked the kill switch, its fine . I have a second engine, swapped the coil, ignition box (not sure what it is called) no joy and those things worked in the second engine. New plugs in both.

What did I miss?

[Tupaia]

Is this 2 stroke or 4 stroke?

[ChrisJHC]

It would help if you defined “won’t start” a bit better.

Completely dead, sputters a bit but doesn’t “catch”, runs for a second or two then dies, etc

All can help track down the issue.

[Tin Tin]

Did you pickle the motor internals with diesel? If not reed valve etc may have corroded and now not functioning properly. Maybe water has accumulated in the fuel filter. It is easy enough to check for spark.

[gonesail]

if no fire whatsoever .. check the kill switch again

[RichKeyWest]

2015 4 stroke. Won't start is nothing. Turns over fine, red indicator light lights, nothing, no sputter at all or difference in speed turning over with choke on or off or more or less throttle.

We are treasure hunters and restore artifacts for a living so treating a salt water encroached engine is a no brainer. Distilled water, salt away, distilled water, corossion x soak, replace fluids 3x, replace carb, exciter coil (starter if present), then immediately start, run 1-3 times a day for 2 weeks.

She ran for those 2 weeks first pull. I am alone right now and can't check for physical spark but with changing ALL of the electronics it seems unlikely its not there.

Tried starting with kill disconnected. Tests with ohms meter, open circuit with lanyard installed, closed with it removed. The good motor tested exactly the same.

I have to be forgetting something. Will have a friend help look for physical spark today, but if I have spark and gas (new carb, new gas) I should be getting something.

[rslifkin]

Give it a shot of carb cleaner into the air intake on the carb. If it at least pops or sputters, then you've got a fuel problem. If it's still nothing, I'd suspect a spark problem. It's unlikely that both cylinders have valves sticking enough to cause insufficient compression to start, so I'd pretty much rule that one out.

[ttex]

Fuel pump diaphragm is torn would be my guess. That is what happened to mine. No idea how it tore. Mine is the Mercury 9.9 so the exact same engine.

I found it to be really easy to work on. I had never worked on an outboard before and I got it figured out and done in a few days.

[Don C L]

I have the same engine. Sounds like no spark, but since it was running fine, that is a bit odd. Did you put a brand new carb on it, or one from another engine?

[RichKeyWest]

Brand new carb on both engines. They both started right up, just had to adjust the idle. Going to work on it now.

[RichKeyWest]

OK the plot thickens.

As I thought, there is no spark. Plugs were wet with gas.

Inspected every wire again



Inspected all sides of connections





I had changed the exciter coil and getting power on pull, light comes on



All grounds are good



Coil and CD Unit were replaced with the same off the running motor, running motor started with the parts from this motor




Coil inspected (remember this and CD ran on the running motor)



Kill switch was checked again, works fine on an ohms meter, and tried starting with it disconnected, no spark still




I don't get it.....

[SV Confianza]

Try cleaning the plugs and try again?

Just had this happen to me. Was going crazy, and the plugs were flooded. Wiped them off and two more pulls it started.

[RichKeyWest]

New plugs, no spark...

[SV Confianza]

Originally Posted by RichKeyWest

New plugs, no spark...

I saw that. Just wondering if they got too wet with the testing.

How did you verify that you don’t have spark? I usually pull the plug, ground the side to the engine, and see if it sparks while I’m watching. I’m sure that’s not a safe way to do it, and you’re supposed to buy a spark plug tester thingy. But when the co captain is looking at me impatiently as I go through trouble shooting tests…

[Don C L]

Originally Posted by RichKeyWest

New plugs, no spark...

So electricity is definitely leaving the coil but doesn't make it to the plug?