Thread: Slow Cranking
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Old 08-06-2018, 06:21 AM
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Walt Walt is offline
 
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 4,874
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Quote:
Originally Posted by rvbuilder2002 View Post
I agree that the NL starter is an upgrade in cranking performance but considering that repeatedly time and again here in the forums I see people troubleshooting with a credit card. It is sad and frustrating to see people spend a lot of money trying to resolve a problem without ever confirming some of the basics. Often times thy even say they have done a bunch of testing but because of lack of experience they didn't get any useful or valid information.
It is for that reason that blindly swapping a part will be the last thing I recommend.
For the most part I agree with the above, however, the starter system is a difficult one to troubleshoot effectively. Trying to crank the engine with a starter that is faulty or "stalled" and take voltage readings is difficult and does not necessarily give valid test results, if you can get any results at all without a meltdown. You can jump the master solenoid to elimate that but the starter and starter sol not so easy.

The big problem with the PM starters is their massive current draw which can easily be upwards of 400 amps, this heavily taxes even the best battery and components in the system. The typical WW starter draws about half that much and therefore the system can tolerate components that are less than perfect, which includes the battery itself. So it takes a "perfect" system to work with the PM starter while the WW units will work fine with something less than "perfect".

The only reason vendors use the PM starter is because it the cheapest and the lightest which make the sales numbers look good.
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Walt Aronow, Dallas, TX (52F) RV7A, IO360, C/S, 1500+hrs

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Last edited by Walt : 08-06-2018 at 06:25 AM.
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