Tohatsu 20HP no=spark

[Jim Mulcahey]

I have a 2011 Tohatsu MSF20C, 20hp 4-stroke that has lost spark after sitting for a few years. I am having a hard time coming up with testing procedures and output values or resistance for the pulser coil, exciter coil, ignition coil and CD unit. Can anyone help me with the service manual pages or procedures for those tests?
This is a carb model with remote controls.
Thanks

 

[pvanv]

Of course everything is in the Factory service manual, available from any dealer. An analog ohm meter will be your friend. How do you know it does not have spark?

 

[Jim Mulcahey]

Spark check has been done grounding a new spark plug to the engine case in a darkened area. I have disconnected all kill switches and unplugged the remote control, to be sure nothing is grounded out. Not finding any pulse coming from the pulser coil when I turn the engine over using the starter, resistance measures about 200ohm on the pulser. I have 18VAC from the exciter coil. No continuity from high tension lead to ground or either wire on the iginition coil.

 

[pvanv]

Sounds like you diagnosed it. BTW, best to use DVA to measure voltages, because the pulse is so quick.

 

[Jim Mulcahey]

I have fuel getting past the float valve somewhere in my carb and leaking out the front and flooding the engine. The float valve and float were replaced and the valve seat looks to be in good shape. Does the check valve located in the side ot the float bowl need to be sealed in place? Mine seems pretty loose.
Anyplace else to look for fuel getting past the float valve?

 

[pvanv]

Flooding has nothing to do with no spark. The check valve is to keep the accelerator pump full, so if it leaked, the worst would be no fuel from the accelerator pump. Re check your needle valve and float.

 

[Jim Mulcahey]

I am quite aware that flooding is not related to no spark, except in the case of wet fouling the plugs. This motor sat outside for six years and something happenbed to the carburetor that I can't see or figure out; new Tohatsu float and float valve, but still flooding throught the main jet badly. I am not a novice when it comes to engines, but do not have experience with this particular one.
You have made it clear that you are more inclined to put-downs than helping, so I'll leave this forum. I'll get it figured out one way or another, just like the hundreds of other engine rebuilds, etc. in the past.

 

[pvanv]

I am quite aware that flooding is not related to no spark, except in the case of wet fouling the plugs. This motor sat outside for six years and something happenbed to the carburetor that I can't see or figure out; new Tohatsu float and float valve, but still flooding throught the main jet badly. I am not a novice when it comes to engines, but do not have experience with this particular one.
You have made it clear that you are more inclined to put-downs than helping, so I'll leave this forum. I'll get it figured out one way or another, just like the hundreds of other engine rebuilds, etc. in the past.

No put downs here; just helping you in the right direction. If you are flooding, the float valve is not seating. Period.

 

[ZaneAK]

Hi, I can't figure out how to post a new question... Sorry for barging in. I may need Paul's help. I have an M18 Tohatsu, 1986. I want to replace the old coil/CDI combo unit with a new coil and separate CDI - can I do that? They no longer make the combo coil/CDI unit. I found a coil 3G2-06040-4 and a CDI 36206060-0. If I can use them, how to wire? Thanks in advance!

 

[pvanv]

I suppose, but I would ask CDI electronics their opinion.

 

[ZaneAK]

Thanks