Motor no start!?

[ethanwerl]

Just joined and new owner of an Older 1986 Tohatsu 9.9 M9.92B. Got this bad boy as a project and now learning project is becoming a pain but i’m just missing something. Since purchase i’ve changed spark plugs, new gear oil, and re did gas lines just for reassurance had fired up and ran a few times but the last few times i’ve worked on it I get no start. (it has misfired a few times before it wouldn’t start again). All help is needed!

 

[coopec]

Are you getting spark at the spark plug? (unscrew the plug, leave it ;laying on the motor (earthing it) then pull the starting cord. Is there spark at the spark plug? If there is spark then look at the fuel system. But it sound more like a fuel problem. I'd start by draining the motor of old fuel a refilling it with fresh fuel.

 

[ethanwerl]

Yes getting spark and fuel was freshly poured with some 2 stroke oil. I will admit that a jet did end up snapping in half while trying to take it out to clean leaving just the threads in the insert but it has started up after the fact

 

[ChromeDome]

Me thinks you need a manual. Google 1986 Tohatsu 9.9 workshop manual and download some.

 

[chriscallender]

Ok you said it ran then after the last few times you’d worked on it it didn’t. So what work did you do those times?

As others have said, with a spark, fuel and compression it should run. The only other thing that can be wrong is if the spark timing is completely wrong eg if the woodruff key is broken and the flywheel has slipped on the shaft, or if the ignition coil is on its way out and it only sparks when the plug isn’t under compression. But 99 times out of 100 it’s the simple stuff that goes wrong and I think what work you did is likely to be a big clue

 

[simonfraser]

Are you getting spark at the spark plug? (unscrew the plug, leave it ;laying on the motor (earthing it) then pull the starting cord. Is there spark at the spark plug? If there is spark then look at the fuel system. But it sound more like a fuel problem. I'd start by draining the motor of old fuel a refilling it with fresh fuel.

intermittent fault could be crud in one or all of the jets / needles of the carb - clean it out ?

 

[coopec]

https://www.justanswer.com/boat/ej4jo-9-9tohatsu-4stroke-electric-start-motor-won-t-start.html

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[PetiteFleur]

Are you using E10 petrol? I now use E5 (premium petrol) with Honda additive and have no further problems. E10 petrol goes off quickly. And as mentioned clean up the jets - you mention one broke? - get a new one.

 

[ethanwerl]

Are you using E10 petrol? I now use E5 (premium petrol) with Honda additive and have no further problems. E10 petrol goes off quickly. And as mentioned clean up the jets - you mention one broke? - get a new one.

that was my next thing, was trying to avoid purchasing all new parts to save some cash but i
leaning towards getting a new one.

 

[ethanwerl]

Ok you said it ran then after the last few times you’d worked on it it didn’t. So what work did you do those times?

As others have said, with a spark, fuel and compression it should run. The only other thing that can be wrong is if the spark timing is completely wrong eg if the woodruff key is broken and the flywheel has slipped on the shaft, or if the ignition coil is on its way out and it only sparks when the plug isn’t under compression. But 99 times out of 100 it’s the simple stuff that goes wrong and I think what work you did is likely to be a big clue

I appreciate this reply, definitely the broken jet is a clue how can you test the coil.

 

[chriscallender]

I appreciate this reply, definitely the broken jet is a clue how can you test the coil.

You can measure the primary and secondary resistance with a multimeter, if you can find out what it is supposed to be from a service manual or the internet. Or get an inline spark checker which fits between the plug and the HT lead and flashes each time there is a spark. This is bringing back memories of trying to get my son's pit bike going when it had no spark :-(