bad starter or bad ground?

[1976CV16]

Motor- 1978 evinrude 85 hp crossflow. Problem- slow starter. First time out my starter spun normally but quickly slowed down. I thought i had bad batteries so i changed out both batteries. Same thing, starter spins but slows down. After it sits it spins strong again for a short time. So i had the starter rebuilt and it works better but still slows down however it cranks much longer than it did prior to the rebuild. Could the starter rebuild be faulty or could this be a different issue? Maybe a bad ground from the battery? I cant find where to ground the battery in the book.

 

[NicoPags]

Hey 1976CV16,

I took had same issue. Simple tests via Continuity will give you an idea on where to begin.

If you have a multimeter available, set to ohms . Place one tester lead on the any part of the frame/casing on the starter, and the other tester lead on where you visibly see where the battery ground is attached too. Should be somewhere near the solenoid. If it has a reading (some multimeters are audible, and you will hear a constant beep) that means the starter case is grounded to the motor.

Now you should test for a short. Take one wire from the multimeter, touch any metal part of the frame of starter, and the other wire should be touched against the positive bolt on the starter. If you have a reading or hear a sound from the multimeter, then you have a short inside the starter and a rebuild may be necessary again. Sometimes the brushes in the starter make contact with the housing case, which causes a short.

If you do end up taking the starter apart again, test to see if the armature is grounded it out. If it is grounded out, it needs replacing. Plently of videos on youtube how to test the armature. (mine was grounded out, it was a sad day)


I just found a short in my starter as well, similar symptoms.

 

[bruceb58]

Put your meter on volts. Put one lead on the starter case and one on the battery negative, Crank and note the voltage measured which is the drop.

Do the same for positive between positive of the starter motor and positive of the battery.

They shoud be equal and not more than a volt or so.

Also measure the battery voltage while you crank. Again should be 12.5V minus the sum of the 2 measurements you just made.

It's really tough to do an ohms measurement for something that has high cranking current since you could be off by fractions of an ohm and fractions of an ohm is the difference between very good and very bad.

 

[glenn property of pam]

battery ground cable should be bolted to the block near the starter or on the starter bracket.
How long are you cranking the engine for before it slows down.

 

[1976CV16]

Thanks all! Ill throw the multimeter on it this weekend and see. The battery is grounded to the block via a small screw in block under the starter. Im going to move it to the starter though. Fishing for an easy fix... Prior to the rebuild the motor would crank for about 2-3 seconds before slowing down to nothing. After the rebuild it will now last 5-8 seconds which is typically all i need unless its cold or i flood it. Still, i dont think it should be doing this. I did not rebuild the starter, i took it to a local starter/alternator place which ive dealt with in the past with good results. Thanks for pointing me in the right direction.

 

[bruceb58]

Do a load test on your battery.

http://www.harborfreight.com/http-w...volt-battery-load-tester-69888-9191-html.html

 

[emdsapmgr]

How does the starter crank if you jump it direct with a set of automotive jumper cables connected to a known strong battery? (bypass the solenoid.) If it cranks normally the problem is in your wiring or the solenoid.

 

[Chris1956]

Corroded battery cables will also cause that behavior. Inspect the cables all along their length. Look for crunchy spots on the insulation, meaning the copper wire is bad under it.

 

[NicoPags]

Bruce and Chris do make some excellent points. Load test and quality grounds are much easier to test considering the components you're testing. My only suggestion was to test continuity not so much the actual ohms reading. However that does seem like a last resort test.

 

[racerone]

Start with an inspection of the starter.---Should be easy if it is a BOSCH unit.