brian_hunt
New Member
I have fuel on the spark plugs and engine is turning over great (new battery).
Some background:
We started having issues approx. 18 months ago – engine would run very rough at high RPM but fine at near idle speeds. I thought there was a water issue in the tank from old fuel, so dumped water remover and SeaFoam in tank and it usually cleared it up (worked 3-4 times), but the issue kept recurring even after using stabilgas and non-ethanol fuel. Issue went away but then starting issue started late last year. Changed spark plugs and it was fine for a while (no rough idle or need for seafoam/water remover any more), then thought it may be a weak battery issue so I put a new battery in (starter was disengaging after 1 or 2 cylinders would start firing). This did not fix the issue (even though battery needed replaced anyway) so I had to change spark plugs again and it fired right up. Now changing spark plugs doesn’t work and the boat left us sit (did not restart after sitting ~1hr) after running great for 2-3 hours.
My diagnostics:
12.6V at the plug for the ignition coil
Continuity and low resistance between ECM and ignition coil plug
Ignition coil resistance:
secondary winding (through coil) tests at ~10 kohms (spec is 9.5-13.5)
primary winding (the coil plug connectors) tests at ~1.8-2 ohms (spec is .85-1.15)
If this increased resistance is enough to keep from starting, it would probably explain the problems I've been having over 18 months. Is 2 ohms enough to keep from starting?
Even if this starts the engine, cost to replace all 3 is $300+, so I'm hesitant to change all three ignition coils out without knowing what caused the problem.
Any thoughts on what else I can check or what may be causing the ignition coils to go bad? Thanks in advance for any help you can give.
Some background:
We started having issues approx. 18 months ago – engine would run very rough at high RPM but fine at near idle speeds. I thought there was a water issue in the tank from old fuel, so dumped water remover and SeaFoam in tank and it usually cleared it up (worked 3-4 times), but the issue kept recurring even after using stabilgas and non-ethanol fuel. Issue went away but then starting issue started late last year. Changed spark plugs and it was fine for a while (no rough idle or need for seafoam/water remover any more), then thought it may be a weak battery issue so I put a new battery in (starter was disengaging after 1 or 2 cylinders would start firing). This did not fix the issue (even though battery needed replaced anyway) so I had to change spark plugs again and it fired right up. Now changing spark plugs doesn’t work and the boat left us sit (did not restart after sitting ~1hr) after running great for 2-3 hours.
My diagnostics:
12.6V at the plug for the ignition coil
Continuity and low resistance between ECM and ignition coil plug
Ignition coil resistance:
secondary winding (through coil) tests at ~10 kohms (spec is 9.5-13.5)
primary winding (the coil plug connectors) tests at ~1.8-2 ohms (spec is .85-1.15)
If this increased resistance is enough to keep from starting, it would probably explain the problems I've been having over 18 months. Is 2 ohms enough to keep from starting?
Even if this starts the engine, cost to replace all 3 is $300+, so I'm hesitant to change all three ignition coils out without knowing what caused the problem.
Any thoughts on what else I can check or what may be causing the ignition coils to go bad? Thanks in advance for any help you can give.