spark from coil but not at plugs..

[Happygolucky]

Hello fellow boaters, new problem with my 5,7 carb TBV …
not sure about the correlation but last trip out the exhaust hose between Y-pipe and elbow cracked .. made it home with lid to engine room open to allow for exhaust to exit and not to suffocate the engine.
Today I wrapped the cracked hose with vulcanizing tape as a temporary fix, however now when I crank the engine refuses to start. After a number of attempts to get running I sprayed starter gas in the carb but not even a cough.
This leads me to suspect ignition so I put my timing light on the no1 plug lead and crank however no blinking of light .
I then put the clamp on the lead going from coil to distributor and now I do have the timing light blinking when I crank!
I take the cap off and expect to see heavy corrosion inside on the contact’s but they all look pretty clean and cleaning them furthermakes no difference.

Could it be the rotor even though it was replace only last summer?
Some say it’s the the distr. sensor that’s gone bad but if it’s broken, there would’nt be any spark from coil (as the timing light blinking do indicate). Am I right ? !

 

[cyclops222]

How many years old is Distributor Cap and the rotor ? The Cap can have a Carbon Track from center down to metal case.
The Timing light is NOT accurate enough to determine H V at different places.

 

[Happygolucky]

How many years old is Distributor Cap and the rotor ? The Cap can have a Carbon Track from center down to metal case.
The Timing light is NOT accurate enough to determine H V at different places.

cap and rotor from last season, I understanding the light cannot say
anything about the quality of the spark/ HV but at least indicate whether it’s there or not !?

 

[nola mike]

cap and rotor from last season, I understanding the light cannot say
anything about the quality of the spark/ HV but at least indicate whether it’s there or not !?

Indicates that you have some electrical impulse but maybe not enough to make it to the plugs. Correct that it wouldn't spark at all with a bad sensor. Did anything get wet? Double check 12v at the coil. Also put a spark tester on the coil lead. If it's strong there then likely the problem is further down stream

 

[Happygolucky]

Indicates that you have some electrical impulse but maybe not enough to make it to the plugs. Correct that it wouldn't spark at all with a bad sensor. Did anything get wet? Double check 12v at the coil. Also put a spark tester on the coil lead. If it's strong there then likely the problem is further down stream

as the exhaust hose broke I guess there was an elevated level of moisture in the engine compartment but it wasnt like it was dripping wet in there. Thanks for confirming my thoughts on the sensor, will go get a spark tester today at ”Biltema” .

 

[Happygolucky]

After getting a sparktester I could actually verify spark to plugs.. this led me to take one step back and look at fuel as the culprit .. I disconnected my fuel hose (which contains a garmin fuel sensor and an inline fuel filter ) and replaced with a hose with primer bulb to allow me to manually pump some gas- and boom, engine fires up. ! Case closed .. until next time...

 

[racerone]

Proper testing / trouble shooting beats the guesswork every time.

 

[Scott Danforth]

Check your compression.

The fact you didn't fill your bilge with water from the exhaust means you bad no water flow

A serious overheat to burn up the exhaust hose may have killed the motor

 

[Happygolucky]

View attachment IMG_3105.mov

 

[Happygolucky]

the hose cracked rather than melted and water did flow .. but you are correct, the portside riser has been getting considerably hotter..