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Crusader 270 Ballast Resistor

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junior4597

Contributing Member
Hey all - looking for a little clarity on this topic. I have a circa 1987 Crusader 270 model that I just swapped out the distributor from a points set-up (Mallory YL670AV) to an electronic one (Mallory YLM 624AV). I have an external coil and ballast resistor. I have a suspicion that the ballast resistor is bad. A few questions:
  • Is there a sure fire was to test these resistors to ensure they are working correctly? I assume multimeter but how exactly, either with key turned on or off? Where do you put the leads?
  • If I have migrated from a points distributor to an electronic one do I still need the ballast resistor? Assuming I'm using the same coil as I had with the points dizzy.
  • If, after testing, the ballast resistor is bad how do I know which one to replace it with? I see there are different types based on ohms. No idea how many ohms my current one is.
I was going to swap resistors from my other engine but thought I'd pop the question up here first - might be an easy test and replace vs. swapping and guessing.

Any thoughts would be great!
 
What is the engine doing? Why do you suspect it is bad. A "bad" ballast would just stop the engine dead. It is usually bypassed when starting, via the key switch, but it wouldn't keep running after that.
Just disconnect it, put an ohm meter across the terminals, should read between 1.5 and 5 ohms. The only thing that could go bad is a break in the resistance element, then would read infinity ohms. Do not run without this resistor, you could overheat your coil and it will fail. Don't ask how I know!
 
plittle2005 said:
What is the engine doing? Why do you suspect it is bad. A "bad" ballast would just stop the engine dead. It is usually bypassed when starting, via the key switch, but it wouldn't keep running after that.
Just disconnect it, put an ohm meter across the terminals, should read between 1.5 and 5 ohms. The only thing that could go bad is a break in the resistance element, then would read infinity ohms. Do not run without this resistor, you could overheat your coil and it will fail. Don't ask how I know!
Click to expand...
I've been dealing with an intermittent stalling issue for a while now on the STBD engine. It only happens at low RPM, the worst time, like when you are backing down into a slip in the wind! I've posted up here about the issue before as it can be fuel delivery or electric. I've pretty much ruled out fuel delivery by - changing anti-siphon valve (both engines share a single tank), replacing the fuel pump, rebuilt the carb, changed fuel filters, tested fuel PSI etc. From the electrical side I've replaced coil, plugs, wires and now fully replaced the dizzy. Next step was to look at the ballast resistor. I threw a meter on it last summer and got a different reading that the reading I got from the port engine, that's why I thought it might be bad. However, I'm sure I didn't test it correctly or know what I was looking for from a ohms perspective.

Anyway, point taken. If the resistor is "bad" then the thought is the engine would be dead? However I wasn't sure, if the ohm number has a range I was thinking a lower ohm number could be caused by a "bad" resistor and possibly cause intermittent stalling. If I pump up the RPM's anticipating a stall it's fine but you know what higher rpm's do to a tranny. Still chasing this down........
 
junior4597 said:
I've been dealing with an intermittent stalling issue for a while now on the STBD engine. It only happens at low RPM, the worst time, like when you are backing down into a slip in the wind! I've posted up here about the issue before as it can be fuel delivery or electric. I've pretty much ruled out fuel delivery by - changing anti-siphon valve (both engines share a single tank), replacing the fuel pump, rebuilt the carb, changed fuel filters, tested fuel PSI etc. From the electrical side I've replaced coil, plugs, wires and now fully replaced the dizzy. Next step was to look at the ballast resistor. I threw a meter on it last summer and got a different reading that the reading I got from the port engine, that's why I thought it might be bad. However, I'm sure I didn't test it correctly or know what I was looking for from a ohms perspective.

Anyway, point taken. If the resistor is "bad" then the thought is the engine would be dead? However I wasn't sure, if the ohm number has a range I was thinking a lower ohm number could be caused by a "bad" resistor and possibly cause intermittent stalling. If I pump up the RPM's anticipating a stall it's fine but you know what higher rpm's do to a tranny. Still chasing this down........
Click to expand...
I had the same low rpm problem, it was carb, bit the bullet, bought a new one, solved the problem. Just "rebuilding" the carb is iffy, hard to do successfully. Also, if you have a water-separating fuel filter (NOT just those little in-line strainers but a real one, labeled as such, about the size of a spin-on oil filter) remove the filter, pour the contents into a clear jar, and see if water is present. Change these frequently if you see water present.
 
junior4597 said:
Hey all - looking for a little clarity on this topic. I have a circa 1987 Crusader 270 model that I just swapped out the distributor from a points set-up (Mallory YL670AV) to an electronic one (Mallory YLM 624AV). I have an external coil and ballast resistor. I have a suspicion that the ballast resistor is bad. A few questions:
  • Is there a sure fire was to test these resistors to ensure they are working correctly? I assume multimeter but how exactly, either with key turned on or off? Where do you put the leads?
  • If I have migrated from a points distributor to an electronic one do I still need the ballast resistor? Assuming I'm using the same coil as I had with the points dizzy.
  • If, after testing, the ballast resistor is bad how do I know which one to replace it with? I see there are different types based on ohms. No idea how many ohms my current one is.
I was going to swap resistors from my other engine but thought I'd pop the question up here first - might be an easy test and replace vs. swapping and guessing.

Any thoughts would be great!
Click to expand...
Measuring the resistance can work but I've found its usually easier to measure the voltage at the coil to assess the health of the ballast resistor.

the need for the ballast resistor should have been determined, explicitly, when the distributor swap was made. With the old mallory electronic triggers, you kept the ballast resistor.

The resistors can fail in a few different manners - again, its usually easier to just replace it if its suspect. As far as the 'correct one', when in doubt, use the OEM specified part number. Typically, any of the 1.5 ohm versions are adequate.
 
plittle2005 said:
I had the same low rpm problem, it was carb, bit the bullet, bought a new one, solved the problem. Just "rebuilding" the carb is iffy, hard to do successfully. Also, if you have a water-separating fuel filter (NOT just those little in-line strainers but a real one, labeled as such, about the size of a spin-on oil filter) remove the filter, pour the contents into a clear jar, and see if water is present. Change these frequently if you see water present.
Click to expand...
Yea, thought it could still be the carb but I did swap it to the port engine and the issue didn't follow. As far as fuel, I do have racors, I eliminated the spin on in-line cans for true water separators. No water in the fuel, plus I have a single tank so the issue would follow to the port engine, you'd think.
 
makomark said:
Measuring the resistance can work but I've found its usually easier to measure the voltage at the coil to assess the health of the ballast resistor.

the need for the ballast resistor should have been determined, explicitly, when the distributor swap was made. With the old mallory electronic triggers, you kept the ballast resistor.

The resistors can fail in a few different manners - again, its usually easier to just replace it if its suspect. As far as the 'correct one', when in doubt, use the OEM specified part number. Typically, any of the 1.5 ohm versions are adequate.
Click to expand...
I have the OEM part number but of course they don't make them any longer. If you think the 1.5 ohm version would work then that narrows down my options well. My other thought, to prove my theory, is to just swap the ballasts to see if the stalling issue follows to port. Easy enough. To be clear though, in your opinion with the "new" Mallory electronic dizzy I am ok to leave the ballast resistor? Instructions say to do so. What is the correct way to measure voltage at the coil? Positive lead to + on the coil and negative to the ballast resistor?? Ignition turned on? I've seen how to test a coil but not in a setup along with a resistor etc. And what resistance number would be in range? I got a different number from my port engine when I tried this, keyed on, but wasn't confident I had my leads in the right spots. Any direction would be fantastic!
 
"I am ok to leave the ballast resistor? Instructions say to do so" Did you mean leave off?

I bought an electronic ignition pickup for my distributor to replace the points and also bought their coil. The instructions said leave off the ballast resistor.

I did so. Then my coil melted from excessive current. This happened TWICE!! Luckily both times at the dock and not out in Lake Superior! So I put the resistor back in and the engine ran just fine and I nver melted the coil again.

Just my experience.

The purpose of the ballast resistor is to be bypassed at start to get hotter spark, then cut back in at run for long term current reduction.
 
plittle2005 said:
"I am ok to leave the ballast resistor? Instructions say to do so" Did you mean leave off?

I bought an electronic ignition pickup for my distributor to replace the points and also bought their coil. The instructions said leave off the ballast resistor.

I did so. Then my coil melted from excessive current. This happened TWICE!! Luckily both times at the dock and not out in Lake Superior! So I put the resistor back in and the engine ran just fine and I nver melted the coil again.

Just my experience.

The purpose of the ballast resistor is to be bypassed at start to get hotter spark, then cut back in at run for long term current reduction.
Click to expand...
No, I kept the resistor in place when I installed the dizzy, per the instructions. Thanks for the heads up on what could happen without it though! I don't want to go down a rabbit hole with my issue thinking it's the resistor but for the life of me I cannot figure out why it keeps stalling! These issues are tough cause the symptoms for fuel delivery and ignition can be similar. I'll be back at it this weekend with more trouble shooting.
 
One more thought: did the engine start running poorly immediately after putting in the electronic ignition parts?

I have a marina buddy who had something similar happen. I will ask him how he fixed it when I see him this weekend.

BTW, did you try just opening up the carb idle screws, and also making sure the choke was opening fully? Is idle speed high enough?

Good luck!
 
plittle2005 said:
One more thought: did the engine start running poorly immediately after putting in the electronic ignition parts?

I have a marina buddy who had something similar happen. I will ask him how he fixed it when I see him this weekend.

BTW, did you try just opening up the carb idle screws, and also making sure the choke was opening fully? Is idle speed high enough?

Good luck!
Click to expand...
No, this issue started before the new dizzy. I also did replace the choke spring, and adjusted mixing screws and idle when I re-timed after the dizzy install. I haven't put a vacuum gauge on but I will try that as one of my next steps. These types of issues are so hard to chase down...Appreciate the perspectives!
 
Again, if you suspect the root cause is your ballast resistor, its easier to just replace it...

as far as checking the voltage, the red lead will go to the coil's + terminal and the black lead will go to GROUND. It would be best if you can keep the meter connected when you induce the failure to see if the voltage is stable at the coil when it happens. It may be easier to just use a test light with a filament bulb - it will draw enough current to show potential issues.

As far as measuring a ballast resistor - they are low value so getting an accurate reading is difficult unless you have a real good meter. On top of that, the value will change with temperature. measuring the resistance in the circuit is usually not recommended.

Another thing to consider is the wiring - 'the wiggle test' can show marginal connections. with the engine running, gently 'tug' at each connector in the IGN circuit - the PURPLE wire from the key switch - at the engine end.

FWIW, give the potential age, you may also want to check the ignition switch - they can go intermittent with age...
 
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