MTH Yellowstone Startuo Problems

I just purchased at a TCA show a Duluth Missabe & Iron Range Yellowstone which is Prodto Sound 1. It has problems starting up on the track except in
one third or the rail. I have checked for leakage voltage when the transformer is down to zero. I think I am finding it likes to start at under 10 volts. It is a 2 8 8 4 and a very nice engine for the price.
If aomeone has an idea why this is happening please reply to this newsgroup. I have a Z4000 transformer with QSI filters on it and a BCR installed.
I am thinking of getting the Lionel mods put in. Does someone have good experience with any particular companies on quality of the upgrades.
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