Dt 115 coil advice

[Jayster]

Hi everyone,

I'm new to posting so please forgive any wrong etiquette!

I have some knowledge of outboards having replaced con rods and pistons on my old 140hp Merc but I'm a little baffled by electronics.

I've just bought what I was told to be a 1985 Dt115. Can't find an engine plate on it anywhere, could it be stamped on the block?... anyway I digress. After manually chocking it and using a little Easystart she fired up lovely. Sounded good too with no knocking (which surprises me now). Ran on muffs only for about 3 minutes so it wasn't quite up to operating temp but I did a comp test anyway and got 90 psi on the bottom 3 and 98 on the top which I know is a little low but they're all within 10% and the engine wasn't proper warmed up. I've been stung on a few engines before so I tested to see if there was a spark at the plugs. Top 3 all good but no spark on the bottom plug. Switched plugs, still no spark. Any ideas please? The coil looks a bit damaged, like its been hit as the bottom securing hole on the block is broken. I'll test the coil on Saturday with a meter to see if it truly is knackered but could it be something to do with the relay befor the coils?

Anyway, IF I need a new coil...

A. Does a CM61-25 have to be specific to the HP of the engine or is it one size fits all?. I've seen them on fleebay advertised as 5hp, 25hp etc.

B.Could I use a CM61-26 with the other 3 25's?

Any other advice on this engine would be very much appreciated. Oh and it's been converted to pre mix as the oil bottle has gone from the outboard, is this common practice?

Thanks in advance

Jamie

[Solarman]

There's not much to "converting to pre-mix", except add oil. I'm sure the oil pump is still in place, flow sensor too i imagine (maybe just unplugged?).

As far as coils, swap one of the other coils temporarily (wire color may be different), should work, if system is ok. Should be able to find a good one by just googling the part #, with item name.

Not sure if serial # is stamped anywhere other than the tag (supposed to be on clamp assy?).

Good luck. Post back when able to let us know how it's going.