tohatsu 15b2 specs help

[ct1762@gmail.com]

Trying to get my old 15hp to run well. it lean pops at idle, like it's out of time, but it isn't. compression is high and even, new suppressor plugs (ngk b7hs-10's) rebuilt carb and set timing. Im an OMC guy, and noticed the plugs fire at the exact same time! Thinking Power pack, but I lost my old service manual and can't find another. the specs for the newer ignition components I have (c and D models). So far I have found this: Primary ignition coil is .6-.8 ohms... supposed to be .2-.3. secondary I get no reading on either plug boot. Is that normal? if i had the correct manual, i could do all the DVA tests and know proper specs, or are they all the same?. Any help would be awesome!

 

[pvanv]

Coil secondary should be very very high, so not unusual to see infinite at a plug wire. Yes, the siamese coil fires both cylinders on exhaust as well as compression. "Wasted spark". The usual issue is being too lean, so confirm 100% that the carb is perfect.

 

[ct1762@gmail.com]

awesome thanks. I forgot to mention: I was running it with the air silencer off, could that be causing it to pop at idle? I'm used to OMC motors were you can usually run most at idle or just above idle without the air box, and it hardly changes things.

 

[pvanv]

You want the air box on. It balances the air/fuel mix.

 

[ct1762@gmail.com]

hey thanks again. Last question: the air box has 2 grommet holes in it, but one is missing. should I fill the other hole to make a good seal? I assume it would contribute to the lean condition it was experiencing...

 

[pvanv]

You want

345671170M

GROMMET

$2.33

 

[ct1762@gmail.com]

Hey thanks Paul. Ordered one up on feebay.