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!999 Sporster runs rough after 4300 rpm


Malibu B.C.

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My 99 Sportster started to run rough after 4300 rpm. The distributor wont adavance past 18 degrees. I found a used ignition module under the seat Im sure it is part of the distributor. But if its been replaced before I'm wondering why? and if in fact thats the problem.

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My 99 Sportster started to run rough after 4300 rpm. The distributor wont adavance past 18 degrees. I found a used ignition module under the seat Im sure it is part of the distributor. But if its been replaced before I'm wondering why? and if in fact thats the problem.

check for corrosion on terminals under distrib cap and or replace

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check for corrosion on terminals under distrib cap and or replace

Thanks very much. I did that and in fact there was an automotive cap on and it was quite corroded. I replaced that and the plugs already. Made no diifference.

I do intend to have it scoped but I was hopping to get the answer here before the exspence.

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Not sure, but 18 degrees advance sounds waaaaayyyyy to much? It is fuel injected right?

Where is timing at idle? Is it hard to start?

Steve B.

According to a Mech. at 2500 RPM it should be way higher than 18 degrees that is where it was reved to when he got 18 degrees. My boat runs like a clock runs perfect starts perfect up to 4300 rpm. Appartently the timming is not advancing to meet the demand. I do not know what the timming is at idle. And its carborated 4 barrel Holly.

Like I said earlier I belive this happened before I bought it ( last Oct.) as I found an used ignition module and a coil too in the boat. I was hopping to find what, why and how this happening.

Thanks Steve

Doug P.

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Thanks for the help. It turned out to be the ignition module in the distributor. Runs great now

I'm guessing my 95 module is the same. Can you tell us or provide a link to the unit you got?

Thanks in advance, ha, advance,

Steve B.

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I'm guessing my 95 module is the same. Can you tell us or provide a link to the unit you got?

Thanks in advance, ha, advance,

Steve B.

I can just go off the box .There was a spare left in the boat. I thought it was a old one at first. OEM Parts. Part number. LX 340 7031 ignition module

The instuctions say its an GM ignition Module although the part has written made in Tawain.

Hope that hepls

Doug P.

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