Batteries (3 Red Tops ~ 6 months ols) show 13.67v; replaced battery harnesses & cleaned connections to OEM cables; replaced dash panel solenoid. On attempting start sounds like starter engages but won't turn over - same from driver station & rear engine station. Jump start with tractor yields same result (has worked in past with low batt). Appreciate any TS help.
Did you check big ground cable from starter to engine block (clean and tighten connections)?
Did you try start with boost switch engaged?
If accessible, try whacking the starter with a big hammer while turning key to "start"? (HEY, it works with old cars...)
Check voltage at the starter while someone tries to start it. A bad battery can show surface charge when on charger, but have very little power for large amp draws. Of course, a poor connection between battery and engine (both positive and ground) will cause the same symptoms.
Only after doing this should you suspect the starter or engine.
It is rare but sometimes the Bendix (starter drive) will get stuck in the flywheel. put a socket on the damper and try to move the engine backwards. If accessible you can use the flywheel teeth to do the same thing. I would check the other possibilities first, but this has happened to me on other engines where the battery was low and didn't have the power to spin the starter drive out.
>Did you check big ground cable from starter to engine block (clean and tighten connections)?
No - setting up to get under coach now & do this. Coach is too low for my profile & I need to add air to raise it.
>Did you try start with boost switch engaged?
Yes. All the components in the isolator area (frame rail behind DS duals) look corroded so I'm not sure boost is "boosting" but jump start attempt failed.
Brett - don't have an assistant now but I will try cleaning connections until one shows up.
David,
Easy diagnosis for boost switch working:
With boost off, check voltage on each side of the boost solenoid-- they will/should be different.
Check again with the boost switch ON. Voltage should be the same on both large lugs.
Add air, and SAFETY STANDS (I hope), before you venture under the coach.
>Add air, and SAFETY STANDS (I hope), before you venture under the coach.
In process now - having to fab stands from a spare fence post.
I think a 4x4 would be less apt to slip. Bigger footprint
Fence post is 5in round.
BIG fence post! I only see up to 2" around here. I am thinking galvanized maybe you are talking wood.
>BIG fence post! I only see up to 2" around here. I am thinking galvanized maybe you are talking wood.
Have to keep the rustlers out (& the horses in).
This happened to us on way down to Alabama on Saturday. Exact same symptoms. Did you notice low voltage at dash with engine idling and headlights on? With us it was a corroded connection. Make sure that every large cable terminal is cleaned and that corrosion has not eaten away inside the insulation. Try to start again and quickly feel every connection. Bad one(s) will be hot.
The quick and dirty way to check is to clamp jumper cables to the battery then one to engine and other to starter solenoid. This bypasses the other cables. Try to start. If still no luck you can put positive clamp to starter terminal. Turn off ignition with you under it. If turns over you have isolated the solenoid as cause. There will be a BIG spark when you do this. Be prepared only to touch the clamp to the starter terminal. We did this when starting reluctant equipment that had to be moved. Don't touch clamps to battery only to engine.
The above is only for who are experienced IE mechanics, or the foolhardy!
Keith
A little Coca Cola (and something to absorb it, if in an area where it might do harm to surrounding area) followed
by a past of soda and water. Then remove the connection, clean it and put back together using a little grease on
the parts. Also the area that David and I hail from do get larger posts, usually old power poles from the electric coop.
Carter Langford
Nac-
Turn your dash lights on and try starting, if the dash light go off you have a dead battery or the starter is shorting out or as crameman
said your bendix is jammed. It could also be the solenoid contacts are dirty. That can be checked with a voltmeter buy checking the starter side of the solenoid when someone is trying to start it
Thanks for all suggestions and support.
Plugged air compressor in to coach & raised to install newly fab'd support blocks.
Cleaned the highly populated starter ground connections and engine block and chassis connections with successful outcome.
M11 started right up but had a Stop Engine (yellow) light. Transmission speed sensor is leaking oil - waiting on part.