Tecumseh TC300 2-cycle - a 25 year problem for me - ignition problem

[Andrewha]

Greetings from Somerset, UK. I'm coming to this forum as there seem to be a lot of knowledgable people looking.

I have a Flymo L400 hover-mower which I've owned since new (about 1997) and the engine is a Tecumseh TC300 ( TC300 3156 (F) ) and the carburettor is a Tillotson HU, and the ignition module a Phelon (Tecumseh #611056, I believe).
The mower has been on the bench more than it's been used - but when it runs. it's really nice. Ignition and strating problems over the years... but I am reuctant to move it on.

There are service manuals available for the TC300 which I have read (but they have to be read with caution as this specific application in the Flymo is not well covered).

Carburation - I have rebuilt the carb with a new gasket kit (there's no after-market for this specific Tillotson - the Chinese $10 item is not the same - I bought one).

Ignition - there seems to be a spark problem. Poor or absent. There is no aftermarket for this Phelon part as far as I can find out - can any one provide info on the specs for this part (resistance over primary and secondary coils) ?
The replacement part is only available in the US, and is very expensive (around $60) ... not certain this is worthwhile.

I am just about to re-terminate the spark plug HT lead in the boot - but after that ... any great suggestions or tips on this infuriating machine ? Thank you.

 

[Rivets]

The biggest things I’ve seen done wrong on these units is not setting the module air gap properly. There are two different gaps, depending on what the TC300 is mounted on. One setting is .317mm and the other is .762 mm. I don’t know which one would apply to the application you have. You might want to try both and see if there is a difference. I’m sure you have the service manual for this engine, but if not here’s one. https://www.mymowerparts.com/pdf/Te...-2-CYCLE-TC-TM-TC200-TC300-ENGINES-694782.pdf

 

[Andrewha]

The biggest things I’ve seen done wrong on these units is not setting the module air gap properly. There are two different gaps, depending on what the TC300 is mounted on. One setting is .317mm and the other is .762 mm. I don’t know which one would apply to the application you have. You might want to try both and see if there is a difference. I’m sure you have the service manual for this engine, but if not here’s one. https://www.mymowerparts.com/pdf/Te...-2-CYCLE-TC-TM-TC200-TC300-ENGINES-694782.pdf

Thanks Rivets for your reply - I saw those two specs in the manual - and it's not obvious which one applies !
I thought it was probably the small gap but I can try the other.

 

[Rivets]

I would try one and then if that doesn’t work, try the other.