87 90 elth loosing fire on top and bottom cylenders.

[bass hunter]

my yamaha 87 elth 90 is loosing fire sometimes on the top and bottom cylenders , any help on this where to look. i found the battery cables were loose .

[rodbolt17]

what tests were made in determining this loss of spark?

[bass hunter]

87 etlh

Pulled the plug and cranked the motor seen no spark grounding to the block.

[rodbolt17]

then you need to do a proper spark test and a CDI input and output test.

[bass hunter]

No spark

If the cdi is going bad what should i look for. The motor ran fine for a mile out on the lake two days ago . When i slowed to fish it sputterd and died . Wouldnt start on the lake brought it home and checked every groung i could find .. Checked the fuse box under the steering wheel . Put the muffs on and the motor started right up.

[rodbolt17]

cylinders 1 and 2 fire of the pulser coils and #3 by the CDI on that engine.
goes back to checking the CDI outputs and inputs to determine whats missing.

[bass hunter]

No spark

Thanks for the info . Im going to take it out in the morning an see if it happers agian. If it does im going to take it to someone with the tools to check everything im hoping its something simple but you know how that goes .