8 Horse Tohatsu won't start

[Juice]

My sailboat has an 8 Horse Tohatsu with dealer installed remote controls. The engine has been tough starting all season. Saturday we went to go sailing. Opened throtlle 1/3, primed the fuel bulb and pulled choke all the way out. Engine wouldn't turn over electrically due to corroded/loose battery terminals. Hand started. Engine fired up on the second pull. Idled for about thirty seconds. About half way through the idle, I pushed the choke in. Ran for about five more seconds then it stalled and will not restart, elictrically or with hand pull.

I have checked in this order...

Plugs - tan, slightly worn, wet with gas - I replaced both.
Fuel - changed out fuel tank with a different tank with fresh gas in it. The old tank has been on the boat since Mid June - Sailors don't use too much of the expensive stuff.
Fuel Filter - clear, fuel flows throgh the filter. Primer bulb will quickly refill the filter after I drained it - I think this would eliminate fuel delivery issues from the tank.
Fuse - the fuse in the power head is not blown
I do see some bubbles in the exhaust while the negine is cranking and there apears to be a hint of faint sheen on the water from the unburned fuel.

Problems appear electrical
Cleaned all battery connections and motor cranks over
Checked all electrical connectiosn for wiring harness - replaced one questionable connection for the lanyard safety switch and the green lead on the ignition switch.
With a multimeter, the lanyard switch did not go to zero ohms with the lanyard engaged. Thoght this could be problem, but bypassing the switch with a jumper didn't help.
I read the ignition switch with the meter - in run, I do not get continuity between the red and blue wires, which I would expect based on the switch table on page 42 of the owners manual. I do get continuity between the red green and blue if I hold the switch in start.
I tried cranking over the engine with the upper plug removed and the electrode grounded to the starter frame - no spark was visible or heard with the engine cranking over- Cylinder was making compression as it cranked over.

So my question is this - should I try replaceing the start switch first or go straight for a new coil?

 

[kandil]

Re: 8 Horse Tohatsu won't start

Did you clean the carb?

 

[Juice]

Re: 8 Horse Tohatsu won't start

Haven't really tried that because the motor is installed in the well on the boat, so I would be working uoside down over the water - too many tiny pieces to fall out.

Althoght the carb probably could stand a cleaning, my big concern is the lack of spark.

 

[pvanv]

Re: 8 Horse Tohatsu won't start

So clearly there is no spark. Check that before condemming the fuel system.

I have a 2007 9.8 Nissan electric (same motor, bigger carb) with remote (RC5) control. Electric (push-key-to-choke) choke. The control has a lanyard stop, and there is also one on the motor. I accidentally knocked the one off the motor once (bumped it with the cowl) while checking the oil. You might check that. Had me scratching my noggin for a minute.

Incidentally, this motor will run without the remote control (but you won't be able to easily operate the throttle and shift if you disconnect the morse cables), so you can always rule out the entire control box circuitry by disconnecting it. 5 wires are involved, and they are easy-to-connect "snap" connectors at the front port side of the powerhead.

 

[Juice]

Re: 8 Horse Tohatsu won't start

Just to be clear, this a 1996 model M8EF 2-stroke with a dealer installed remote controls.

I get some confusing readings on the switch - the contacts for the blue lead only engage when pushed in -which I have never done when operating the motor. Does the switch have any effect in the run position? Should the lanyard switch indicate shorted or open with the lanyard installed?

 

[Juice]

Re: 8 Horse Tohatsu won't start

So clearly there is no spark. Check that before condemming the fuel system.

I have a 2007 9.8 Nissan electric (same motor, bigger carb) with remote (RC5) control. Electric (push-key-to-choke) choke. The control has a lanyard stop, and there is also one on the motor. I accidentally knocked the one off the motor once (bumped it with the cowl) while checking the oil. You might check that. Had me scratching my noggin for a minute.

Incidentally, this motor will run without the remote control (but you won't be able to easily operate the throttle and shift if you disconnect the morse cables), so you can always rule out the entire control box circuitry by disconnecting it. 5 wires are involved, and they are easy-to-connect "snap" connectors at the front port side of the powerhead.

To the best that I can tell, there is no lanyard switch in the power head and the original electric start button was removed when the remote controls were installed. I've disconnected the wring harness from the switches in the boat -do I have to make any changes in the powerhead to get to to run or start manually?

 

[TOHATSU GURU]

Re: 8 Horse Tohatsu won't start

Did you ever determine if there was spark getting to the plugs?

 

[Juice]

Re: 8 Horse Tohatsu won't start

Definitely no spark at all. I also opened up the fuel pump. It was clean as whistle, everything shiny and no gunk or slime in it. Diaphragm was not crracked or ruptured.

 

[kandil]

Re: 8 Horse Tohatsu won't start

Just to be clear, this a 1996 model M8EF 2-stroke with a dealer installed remote controls.

I get some confusing readings on the switch - the contacts for the blue lead only engage when pushed in -which I have never done when operating the motor. Does the switch have any effect in the run position? Should the lanyard switch indicate shorted or open with the lanyard installed?

with the lanyard installed it is open. you can disconnect the switch from the harness and the motor will start if the switch was bad!!! to turn off you can connect a Small wire to where the SW was hoked good luck

 

[TOHATSU GURU]

Re: 8 Horse Tohatsu won't start

If you have no spark then your next steps are simple. You stop. You get a service manual. You perform the ignition test procedures. Or you waste time and start ordering parts that you don't need.