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Discussion Starter #1
I am working on an Onan b48m. It was running great but when I went to start it this weekend it wouldn't run good. It would idle badly and really didn't want to rev. I have completely replaced the fuel system, and removed the carb, cleaned it, new carb kit, plugs checked intake and checked spark. I am getting spark put its not the brilliant pop it should be. My tester only goes down to 200 ohm but it tested the coil at 5.9 to 9 ohms and wouldn't stay consistent. Would a bad coil cause a engine to run rough, and act like something is terrible wrong.? How do I check condenser, I am not sure what setting to put my tester on?
 

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Gravely1964
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I am working on an Onan b48m. It was running great but when I went to start it this weekend it wouldn't run good. It would idle badly and really didn't want to rev. I have completely replaced the fuel system, and removed the carb, cleaned it, new carb kit, plugs checked intake and checked spark. I am getting spark put its not the brilliant pop it should be. My tester only goes down to 200 ohm but it tested the coil at 5.9 to 9 ohms and wouldn't stay consistent. Would a bad coil cause a engine to run rough, and act like something is terrible wrong.? How do I check condenser, I am not sure what setting to put my tester on?
Bad coil will do some weird things. Had a miss in my 48 willy's jeep one day. Kinda figured bad plugs since it ran. Next week no spark at all. Coil went so it does happen.

Those carbs are a PITA to get correct some times too so double check no fresh dirt got in the carb and or bad gas
 

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Discussion Starter #3
I am 100% positive my carb is clean. With all the steps I take I know that is good. I am trying to figure if my condenser or my coil is the culprit. I am not strong with electrical work.

First pic shows my meter
Second shows what it reads
Third shows how I am testing it. Also I just noticed the black piece in the center of the coil has a crack?
 

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Gravely1964
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I am 100% positive my carb is clean. With all the steps I take I know that is good. I am trying to figure if my condenser or my coil is the culprit. I am not strong with electrical work.

First pic shows my meter
Second shows what it reads
Third shows how I am testing it. Also I just noticed the black piece in the center of the coil has a crack?
Not sure what it should measure out to, but if the plastic is cracked its getting moisture inside and its only a matter of time.

Also thats the new style coil as well been replaced at some point already.

See if Boomer comes along, or Richardtx and says what it should test to and be good.

If you replace the coil put a new condenser on with just an fyi
 

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Discussion Starter #5
I believe the coil is supposed to be around 3 ohms. But good advise replace both and it can't be either lol
 

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Discussion Starter #7
Any body? I would like to order the parts tonight
 

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I would call Boomer and have him send a coil and a tuneup kit (points and condenser)
 

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Discussion Starter #9
Does it sound like a bad coil to you?
 

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Discussion Starter #10
I will start ordering parts I guess. The points and condenser are a year old and coil is is 2 years and has maybe 25 hrs
 

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dayton
the coil you show should be 3.87 to 4.73 ohms for the primary.
you do need to deduct the resistance of
the leads and internal resistance of your meter.
touch the leads together and record that reading,
and subtract it from your reading.
you have not stated anything about your plug wires.
thank you. boomer
 

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dayton
i forgot to add the secondary ( leads in the towers )
should be 37.800 + or - 10% for this late model coil.
set the meter at 200K.
thank you boomer
 

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Discussion Starter #13
I will go test it now
 

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Discussion Starter #14
The coil reads 40.100
The wires are 1.2 and 1.6
The meter has 1. Reistance so does that make my coil 4.3?
 

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Discussion Starter #15
And my wire .2 and .6?
 

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Discussion Starter #16
Boomer do you have a coil and condenser on hand, I would like to order both. I think that If it's just the condenser it wouldn't hurt to have a spare coil
 

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Discussion Starter #19
I will call tomorrow, in the afternoon sometime. Thanks
 

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Boomer do you have a coil and condenser on hand, I would like to order both. I think that If it's just the condenser it wouldn't hurt to have a spare coil
+1 +1 +!!!

Spares are wonderful. Once you get them, you never need them. :sidelaugh
 
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