[besclavon]

Let me start with, I have been reading the forum for a while and i appreciate all the info and help on self diagnosing my engine problems. Now I am stuck and have read all i can and i would appreciate some advice.

I have a 9.8 HP 1970 mercury 110. I bought it this winter. Previous owner said it has hardly been used by his father, but its been sitting around a long time. The impeller was changed this winter and it was tuned up and running. I started it a few times in march (it ran fine in idle and high rpm) then i had some bad gas and a bad fuel delivery system. I replaced the hose/bulb/tank and it cranked one more time, then it wouldn't start after that. I read the forums and replaced the spark plugs and they fire. I then noticed that the plugs were clean and it appears as if the engine isnt getting fuel. Fuel was getting to the float bowl, but not coming out air intake when priming the bulb. I checked compression and both cylinders and they are 85 and 80 psi - in reasonable range (from my reading) unless i hear otherwise. I then replaced the engine to fuel pump vacuum hose and the fuel supply hose to the fuel pump. I rebuilt the fuel pump and now the bulb pumps nice and tight and stays that way(it was lose before - one way check valves in pump were bad). I then cleaned out the carb and put it all back together. It still wouldnt start. So i broke the carb down and soaked it in cleaner over night. I cleaned all the channels and jets out with copper wire strand from a 6 gauge cable and rebuilt the carb with a new kit again (including inlet needle and float). The carb is spotless and clean. I also checked the reeds and they were not cracked or broken. I could see 2 of them from the carb intake port on the bottom of the engine block. I am stuck now. I still dont think the engine is getting sufficient fuel. Before, i would prime the bulb and when it was tight, some would leak out air intake port in the carb. Now it doesn't. It will putter and back fire once every once in a while cranking it, but it does not start. I am lost now, any ideas or directions to pursue would be great. I am wondering if my spark is strong enough. how could i tell that other than color? should i adjust the points or maybe there is a timing issue? I dont mind doing some research, but i no longer even know what to search for because i have exhausted my options. I really want to get this myself without having to take it to a mechanic for personal pride and knowledge, but it is looking like going fishing on the 4th is out. No one can around can repair it for a few weeks. Look forward to the replies.

[longjohn119]

Best way I know to check for a weak coil is an adjustable spark gap tester, they look something like this
http://www.eastcoastmarineservice.com/LIS-50850.jpg
And you can get them at many auto parts stores for around 10 bucks

A solid state (Breakerless) ignition should be able to jump a 7/16" or larger gap with a nice blue spark, a breaker points ignition should be able to jump a 1/4" gap if I remember right, but you might want to double check that figure

One thing I like to do when troubleshooting a no start is squirt a little mix into the sparkplug holes and put the plugs back in and try it. If it starts (and dies) your coils are probably OK and you have a fuel delivery problem, if it still doesn't go you most likely have some sort of ignition problem

[besclavon]

I forgot to mention i was shooting in some premix when i would start it. Sometimes it would pop once or twice and sometimes it would do nothing. i would say it would pop 1 out of 4 pulls with premix. That is why i cant decide if it is electrical or fuel related. I guess i will go talk to an autoparts store to see if i can borrow a spark plug tester.