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Starter or something else?

n25801

Member
Got in the plane the other day and went to crank - prop turned slowly and wouldn't start. Figured the battery was done as it was 6yrs old got a replacement PC680 dropped it in same thing. Cleaned all the connections on battery, ground to engine, ground to airframe, relays, etc. Ran voltage at battery 12.8, ground 12.8, relays 12.8 (no load) went ahead and replaced the starter solenoid as it was old to. Checked voltage at battery while cranking went to ~6V, obviously that's the problem. Question is besides starter (delco remy) is there anything else that could drop the Voltage like that?
 
Yeah started there that's how I know the voltage drop when cranking. It says battery but I tried 2 different ones with the same result. Ohms where less that .2 in step 4
 
Battery Relay

I had the same problem a few months ago. I replaced both battery and starter relay. It turned out the battery relay was the problem. In all my years of flying that is the only battery relay failure I've experienced.

I spent the extra bucks for a battery relay with the highest AMP capacity. The uncertified battery relay was rated at nearly half the AMP rating of the top certified relay Aircraft Spruce sells.

Due to the heavy I0360A1B6 in the Doll's nose, I mounted the Concord 25AH battery in the back. That required a long wire run to the starter. My cranking RPM kept falling, and a new battery did not improve it much. With the new relays installed, my cranking RPM is as fast as other RV-8 with a forward mounted battery.

I hope this helps. Good luck.
 
thanks, I was thinking for the cheap $$ I would do that next just hate to keep throwing money at it if its the starter.
 
thanks, I was thinking for the cheap $$ I would do that next just hate to keep throwing money at it if its the starter.

There is a larger copper bar in that starter to feed the windings and mine cracked with very similar symptoms. Cranked but very sluggish. Never checked voltage drop.
 
When installing a master or starter solenoid, be careful not to rotate the stud that you are installing the cable. If rotated, it will reduce the contact surface of the stud (ears to the internal contact disc) and not allow high current to flow.
 
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rotate the stud? do you mean over torque so that it rotates?

Yes. Each stud has two nuts on each one. Remove only one nut, install the cable and nut. Hold the inner nut with a wrench as you tighten the outer nut so you won't rotate the STUD that passes through the housing. This is an important connection to reduce losses to the starter, so it must be tight, without rotating the stud.

This is also a good location to coat each contact surface with DE-OX. https://www.lowes.com/pd/ILSCO-De-Ox-Oxide-Inhibitor-Petroleum-Base-8-oz-Bottle/5013206465
 
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