Slow engine starter cranking

[Frank McElroy]

Since purchasing my coach new in 2007, I always thought my coach ISL  engine cranked slower than I expected using the starter batteries.  I chaulked it up to that's the way it is until a while back I noticed other ISL engines cranked over much faster than mine.

Well, I found the problem.  Actually two problems.  First, I upgraded the small chassis battery cables connecting the two chassis batteries from 2/0 to 4/0 cables.  One was getting hot, because of a poor crimp so I made two 4/0 cables.

The other issue was at the starter ground lug.  On mine, access is extremely limited because of an engine hydraulic pump bracket.  A standard box wrench won't fit.  To solve this problem, I used a thin wall 3/4" deep well impact socket with a 3/8 to 1/2" drive adapter.

I found 4 wires connected to that starter ground lug.  Two 4/0 cables (one from battery ground and the other to the chassis frame rail) and 2 smaller lugs going to starter related relays.  One of those small lugs got caught in the stud threads next to the nut preventing a tight ground cable connection to the starter.

So, I repositioned both small lugs against the starter first, then the two 4/0 ground cables, then a lock washer (Monaco didn't use a lock washer) then the nut.

Pictures are worth a thousand words.

Hopefully this might help someone who has a similar problem.  Oh, and yes, now the engine starter spins like a top - faster than it ever did when new!

[Paul J A]

Monaco used the wrong sized cable from the battery to the starter on my 07 ISX 525. It was always hard starting. I had the cables replaced with heavier ones and that took care of the hard starting. A friend of mine did the same thing to his  2006 ISX 600. 

[Brett63]

I have the slowest cranking engine I have ever seen. I have the 650 Cummins