Starter issues (I know, another thread)

[John316]

Folks, I just read David Anderson's whole thread. I figured I might as well start a new one anyways.

We have the Mt 39 style on our bus. No problems for the last two years. Recently when it sits over night, and we go to start it, we have a strange sound. It isn't a typical clicking, and it isn't something that I have heard before. It is more of a hammering sound. The engine doesn't sound like it is turning over, just this loud hammering sound that I can hear from the front. As soon as I let off the starter button, and hit it again, the bus fires right up. Then it will start all day long, with no problems, until the next morning.

I am guessing that it is the solenoid. Mostly because I can't figure out what else it would be. All connections are good, everything looks perfect. I pulled it this afternoon (those things are a breeze to yank, less then 1 hour). Tomorrow AM, I am taking it to the electric shop to have them check it out. I am thinking that I will get this one rebuilt and keep it for a spare, and put a new one in. I can get a brand new Mitsubishi for 300.

What do you all think? Btw, I have a spare alternator sitting in the bay too. I don't want to lose that on the road and not have a replacement, lol.

John

[Busted Knuckle]

John,
Where you get'n a brand new Mitsubishi for 300? I'll trade you a brand new alternator for 3 of those Mitsubishi's!
  BK 

[TomC]

If you're carrying a spare 50DN alternator-that's an extra 100lbs of weight.  If you have a normal alternator-I know we have 160amp Leece-Neville 12vdc NEW alternators for $160.00.  Hardly worth it to carry an extra.  Course-if it is a 24vdc alternator-then they are harder to find on the road.  Quite frankly-I don't understand why American big rig trucks use 12vdc, when practically all the rest of the world big rigs use 24vdc?  Good Luck, TomC

[John316]

BK, I will let you know what I find out, when I am there today. That is what he told me on the phone, and when I have the receipt I will believe it.

Tom. You nailed it. 24V 50DN. That thing is a horse, but I figure oh well. We are in the process (read should happen soon) of hooking our alternator up to our house batts. It is 24V, so that adds another degree of complexity.

BUT, we are also thinking of mounting another alternator on the spare pulley for house battery charging, then downsizing the start battery alternator. What do you think?

Thanks,

John

[bevans6]

My conclusion, after thinking about things a lot, is that the reason for the 50DN in our buses is to power an on-the-road  high current inverter, usually to run air conditioners while travelling, or to run the OTR AC or heat fans.  I power a 3,000 watt inverter, my start batteries are bridged to my 24 volt house batteries while driving so everything gets powered and charged.  I find it a completely simple and effective solution.  If you don't have and never plan to do such a thing, then you have no need for a big alternator.  The draw load of the bus while travelling (not running stock OTR AC or heating, so neither of the two big fans) is only around 50 amps at 24v if you are lit up like a christmas tree, running driver's heat, basically everything on.  Start batteries get recharged over time so they don't need 270 amps from a 50DN.  If you do retain the OTR heat, that fan is fused at 80 amps.  So the minimum alternator output would be around 125 amps at 24 volts sustained if you retain the stock heater fan.

House batteries can probably be charged up fine with as little as 50 amps if you run a separate alternator.

Brian

[luvrbus]

Probably the soft start on the starter going bad John I have a idea Cole is reading this saying I told you so lol but he can't say much I noticed a Delco 39 on his series 60 

good luck

[gus]

You could have a slight misalignment in the starter and flywheel gears, not hard to do when replacing starters.

This gives the same symptoms as an electrical dead spot in the start motor.

[John316]

Thanks for the replies, folks.

I paid $250 for the brand new starter. It is not Mitsubishi, but another brand. The gent at the shop said that he liked these better. I noticed it was made in Taiwan, and not China like Mitsubishi. Also, I liked the way that it was assembled better.

He bench tested our starter, and it performed perfectly (as I told him it would). He really thought that we were having voltage issues, but I wasn't too convinced. He said that he would keep running it, and said that he thought we could get a while longer out of it.

Anyways, I purchased the new starter, and that is going to be packaged up and will stay with us. That way, I can replace it anywhere I have an hour to spare, if needed. I put the old one back in, cleaned all the connections (which weren't too bad at all). Sneezed everything, and made sure my voltage was good. Time will tell if that fixes it or not. I am a tad skeptical, but I have my backup all ready to go.

Brian, I agree with you. That is our plan, but hasn't happened yet. We have two 4K watt inverters that we always run off of. I really don't think that we will change to two smaller alternators, at least for a while. We have a brand new 50DN sitting there that I won't get rid of, LOL.

Thanks a lot.

John

[bevans6]

these days, a brand new 50DN is probably a good stock market hedge...      

Brian