Outboard - no sparks

[seadog30]

I have a rarely used Tohatsu 3.5 HP 4 stroke, on the one or two times a year it has been used it has always been a good starter.

While checking it over (no point having a spare that does not work) it would not start.

After checking fuel circuit, jets etc I took out the spark plug and found no spark.

The usual suspect for electrical faults is the safety cut out switch, tested no faults, I changed the spark plug for a new one and made sure that all the connections were OK.

Am I correct in thinking that the fault must be in the encapsulated ignition coil ?

Regards - Seadog.

 

[Yngmar]

Yup, sounds like it. Had the same on our Suzuki 2.5 DF - found a used magneto off eBay and that did the trick. New part a bit pricey.

Probably this one? https://www.tohatsu.us/index.php?ma...=1000_1021_1030_1031_13199&products_id=111434

 

[VicS]

I have a rarely used Tohatsu 3.5 HP 4 stroke, on the one or two times a year it has been used it has always been a good starter.

While checking it over (no point having a spare that does not work) it would not start.

After checking fuel circuit, jets etc I took out the spark plug and found no spark.

The usual suspect for electrical faults is the safety cut out switch, tested no faults, I changed the spark plug for a new one and made sure that all the connections were OK.

Am I correct in thinking that the fault must be in the encapsulated ignition coil ?

Regards - Seadog.

Yes I agree if you are absolutely sure that it is not the stop switch, or a short in its wiring, there is nothing else it could be. ( HT lead OK ? but thats part of it anyway))

You don't say exactly what model you have, or give its age . The actual part required will depend on whether it is a 3.5A or a 3.5B ( the change being during 2009)
Check the Tohatsu parts lists at https://www.tohatsuoutboardparts.com/

 

[Boathook]

Double check to no spark as my Malta had the same problem many years ago. I then found out that the spark was very weak, even from new and wasn't really visible in bright light. Also trying to find bare metal for the earth wasn't easy without removing some 'paint'.

 

[seadog30]

Thanks all.

I have now rechecked the coil resistance the secondary coil is as per workshop manual, the manual does not give a resitance figure for the primary ?

VicS - Thanks - the engine is 2006, yes I have checked and double checked the stop swt and the wire continuity and remade the plugcap end of the HT lead.

I will start looking up ebay for a replacement coil.

Regards - Phil

 

[seadog30]

Solved !!!!!!!!!

Thanks again to all who contributed, I thought you might like to know what happened.

After looking up the cost of a new ignition coil and getting a shock I decided to have a look at my other outboard for clues.

The only thing I noticed with the other engine was that the magnet on the flywheel on the other enging felt much stronger ! . exposed the flywheel on the Tohatsu and remagnetised the magnet. I now get a nice big fat spark !!!!!!!!!!!!.

Regards and thanks - Phil

 

[VicS]

Solved !!!!!!!!!

Thanks again to all who contributed, I thought you might like to know what happened.

After looking up the cost of a new ignition coil and getting a shock I decided to have a look at my other outboard for clues.

The only thing I noticed with the other engine was that the magnet on the flywheel on the other enging felt much stronger ! . exposed the flywheel on the Tohatsu and remagnetised the magnet. I now get a nice big fat spark !!!!!!!!!!!!.

Regards and thanks - Phil

How did you remagnetise it ?

 

[seadog30]

Hi VicS

I have a very powerrfull ex speaker magnet and used the traditional stroke method untill the coil lamination assembly was as difficult to pull off as on my other engine.

Regards - Phil