9.9 Tohatsu B.2 2 stroke Runs good for short period, dies, then restarts instantly

[tohatsu9.9guy]

I have a early/mid 90's 9.9 Tohatsu 2 stroke outboard, and I just did the throttle advance cam swap on it. Right after I finished doing the swap, I went to the lake to test it out. It ran great for the first 15 minutes, but as I was going across the lake at WOT it suddenly shut off, like someone hit the kill button. It started right back up, and I ran it at 3/4 throttle for about 45 seconds, and it did the same thing. It continued to do this all the way back to the dock, starting right back up each time. It would die after 45 seconds to a minute if I ran above 1/4 throttle. What could be the cause of this? Could it be something related to the throttle cam swap? It seems to me like it is ignition related, but why would it run fine for short amounts of time then all of the sudden die? Any help would be greatly appreciated.

 

[deejaycee_2000]

Re: 9.9 Tohatsu B.2 2 stroke Runs good for short period, dies, then restarts instantl

Welcome to the forum ...... make sure you have enough ventilation at the tank ..... if you do check the reed valves .....

 

[pvanv]

Re: 9.9 Tohatsu B.2 2 stroke Runs good for short period, dies, then restarts instantl

Troubleshooting time. Start with the very basics. Verify no fuel restriction (especially venting). Verify no kill switch wiring flaws. When the motor quits, inspect a plug to see if it's soaking wet with fuel (no spark) or not.

 

[tohatsu9.9guy]

Re: 9.9 Tohatsu B.2 2 stroke Runs good for short period, dies, then restarts instantl

I am pretty certain it is getting plenty of fuel, as the bulb is hard and it started right back without pumping the bulb, and also it shut off like it wasn't getting spark, not slowly like it was out of fuel. I will check the reed valves though. Much appreciated!

 

[Wee Hooker]

Re: 9.9 Tohatsu B.2 2 stroke Runs good for short period, dies, then restarts instantl

Simple test, Get/ install a in-line spark tester and run the motor till it dies. As it quits note to see if the tester still lights up. If it stays lit it's not a spark issue.

btw, You can get these very inexpensively at places like harborfreight.com.

 

[tohatsu9.9guy]

Re: 9.9 Tohatsu B.2 2 stroke Runs good for short period, dies, then restarts instantl

I went back to the lake today, after tightening all of the screws related to ignition (coil plate, grounds, etc.). My motor was still doing the same thing. Kept dying out shortly after reaching 1/4 throttle or higher. This time it was a little harder to start back up though. I came home, cleaned the carb and fuel filter/lines, and there was a small amount of dirt in the filter and carb. I started the motor after reassembling it, hoping the problem would be solved, but unfortunately it still died out after about 30 seconds of running at around 1/4 throttle. It is for sure getting fuel. What could the problem be??? CDI box? Hopefully something cheap!

P.S.
When I was putting the carb back on, I noticed that the kill switch wires were hooked up backward into the wrong connectors (black into brown, brown into black). I started the motor hoping this was the problem, but it shortly died out again. Could this have ruined some electrical component? Please help! Sorry this is so complicated.

 

[pvanv]

Re: 9.9 Tohatsu B.2 2 stroke Runs good for short period, dies, then restarts instantl

The kill switch would work regardless of the wiring. It's just like a doorbell button (momentary spst switch), that grounds out the input to the cdi. You might want to check spark. Could be a CDI/wiring issue.

 

[tohatsu9.9guy]

Re: 9.9 Tohatsu B.2 2 stroke Runs good for short period, dies, then restarts instantl

Update: The pulser coil was the problem. Determined it was bad through resistance testing with a multimeter. Swapped one from my parts motor and it runs as good as new now.

 

[Sea Rider]

Re: 9.9 Tohatsu B.2 2 stroke Runs good for short period, dies, then restarts instantl

You have converted a 9.9 to a 15 by swapping 15 cam, do you have butterfly set to 180? when at wot ?

Happy Boating

 

[isaksp00]

Re: 9.9 Tohatsu B.2 2 stroke Runs good for short period, dies, then restarts instantl

I think Luis posted his last comment to wrong thread.

 

[tohatsu9.9guy]

Re: 9.9 Tohatsu B.2 2 stroke Runs good for short period, dies, then restarts instantl

yes, butterfly is set to 180 degrees