No spark with plugs IN the cyclinders

superhondaz50

superhondaz50

Location
Fort Mohave, AZ
Troubleshooting my 750 small pin. No spark/no start. When I let off the starter I get a couple flickers of spark. This is using a second set of plugs (one set in cylinder, on set in the plug caps grounded to head.) If I remove the plugs from the cylinders (plug holes open) and crank, I get good spark. I tried two different batteries, both are from 06/23, both have been kept on tenders. I am waiting for one the trickle charge back up to test again.

Thanks for the help.
 
WFO Speedracer

WFO Speedracer

A lifetime ban is like a lifetime warranty !
Location
Alabama
superhondaz50 said:
That's what I'm thinking too. Just confused as to why it'd spark with no compression and not spark with compression, what causes that?
Click to expand...
A stator is a coil of wire with a magnet spinning around it , the faster it spins the more voltage it produces , it spins much faster with the plugs out than it does with them installed.
 
superhondaz50

superhondaz50

Location
Fort Mohave, AZ
superhondaz50 said:
That's what I'm thinking too
Click to expand...

WFO Speedracer said:
A stator is a coil of wire with a magnet spinning around it , the faster it spins the more voltage it produces , it spins much faster with the plugs out than it does with them installed.
Click to expand...
Gotcha makes sense. Should it still be producing spark with a weak battery? I usually replace my battery every season. This year I didn't use this ski so it's a battery from 2023. I am wondering if there are dead cells in the battery.
 
WFO Speedracer

WFO Speedracer

A lifetime ban is like a lifetime warranty !
Location
Alabama
Yep anything below 10.5 volts while cranking is not good , a damaged starter or weak battery can both be culprits here , I have seen some starters out there that drew tremendous amounts of amperage.

If I was working on this ski the first thing I would do is put a known good battery in it , just for elimination purposes if nothing else , my philosophy on electrical diagnostic is start with the simple stuff first eliminate that , new battery , unplug the stop switch and go from there .
 
Last edited:
S

Storbeck

Location
Minnesota
WFO Speedracer said:
Yep anything below 10.5 volts while cranking is not good , a damaged starter or weak battery can both be culprits here , I have seen some starters out there that drew tremendous amounts of amperage.

If I was working on this ski the first thing I would do is put a known good battery in it , just for elimination purposes if nothing else , my philosophy on electrical diagnostic is start with the simple stuff first eliminate that , new battery , unplug the stop switch and go from there .
Click to expand...
I recommend do what wfo is saying here.
 
WFO Speedracer

WFO Speedracer

A lifetime ban is like a lifetime warranty !
Location
Alabama
Jiffyjet said:
I have had weak magnets in the flywheel cause the same thing…
3 of them were Jetinetics charging wheels on a 550
Click to expand...
jetinetics flywheels are notorious for this , I also have a really nice Jetinetics paperweight - doorstop for a 550 here somewhere .
 
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