qd-15 with weak spark on top cylinder

[ferd66]

Hi Guys,

I just picked up a qd-15 in a boat, trailer, motor package deal. Guy said the motor ran but needed a tune-up. Because of the package price($350), I bought it without checking the motor over real well. Brought it home, it appeared to have no spark on the top cylinder. I then used an air gap tester and found that the top had spark, its just not as bright as the bottom cylinder. Changed points, condenser, and coil and it made no difference. Only thing I haven't changed yet is the plug wire. Would that make the difference?

I put it on the boat and ran it tonight on the lake. Seems to run fantastic. Idles at 1.3mph and tops out at 20.7 on gps. Quite surprised by the performance.

 

[Daviet]

Re: qd-15 with weak spark on top cylinder

If it aint broke, quit try'n to fix it.
What distance did you have the tester set at?

 

[bktheking]

Re: qd-15 with weak spark on top cylinder

Sounds like it's on par, what boat, my qd-12 did 18 on my 14 ft crestliner aluminum.

 

[ferd66]

Re: qd-15 with weak spark on top cylinder

not sure off the top of my head. between 1/4" and 3/8" if i had to guess. It just seemed like a big difference in the intensity of the spark.


It's on a 12' Meyer semi-V

http://www.youtube.com/watch?v=ZmF7XBoa37Y

 

[bktheking]

Re: qd-15 with weak spark on top cylinder

Runs like a champ, if it were down on spark you'd know it.

 

[1946Zephyr]

Re: qd-15 with weak spark on top cylinder

Hi Guys,

I just picked up a qd-15 in a boat, trailer, motor package deal. Guy said the motor ran but needed a tune-up. Because of the package price($350), I bought it without checking the motor over real well. Brought it home, it appeared to have no spark on the top cylinder. I then used an air gap tester and found that the top had spark, its just not as bright as the bottom cylinder. Changed points, condenser, and coil and it made no difference. Only thing I haven't changed yet is the plug wire. Would that make the difference?

I put it on the boat and ran it tonight on the lake. Seems to run fantastic. Idles at 1.3mph and tops out at 20.7 on gps. Quite surprised by the performance.

Spark plug wires can make a HUGE difference and so will how good the coils are mounted. The coils have to be mounted to where the face matches up the machined area on the mag plate perfectly, or they may not deliver the right spark (or not at all.) I usually replace the wires, when I replace the coils, just to make sure that I'll have the longevity.