Starter Motor Buzz

[leadrsa729]

Hello -

I just put the motor back into my 72’ 911. Built up the pressure with the starter motor, and let it sit for a few days. Went back to it and the starter isn’t working anymore. I get lights and the fuel pump turns on, but when I turn the key all the way everything turns off and the starter makes a horrible buzzing noise. It’s louder than the fuel pump so I’m not sure if that is cutting power as well.

Took the starter out and bench tested it using a different battery and it works fine. Do you think I need a new battery or is something else going on? I had a 40 amp charge going to the battery while trying to start as well. I also cleaned the ground strap on the transmission and the contact point.

Thanks for any help or tips you can give me!

[leadrsa729]

Hi Everyone -

I was able to get some video of what's happening. You can listen to the same sound I'm hearing at the below link.

https://photos.app.goo.gl/iMEj7a8mCdQmWDLGA

Thanks again for any help you guys can give me!

[pors1968]

Try to turn engine using crank pully.Your engine might be seize.

[leadrsa729]

Thanks for the suggestion! I did try that. Turned it over by hand a full rotation. It was tight, but I didn't feel like it was anything out of the ordinary.

[Bob Kontak]

Originally Posted by leadrsa729

Took the starter out and bench tested it using a different battery and it works fine. Do you think I need a new battery or is something else going on? I had a 40 amp charge going to the battery while trying to start as well.

Talk about the spin up for oil pressure. Any oddities then? Were plugs in?

The buzz thing is what has me baffled. It's trying. Usually with a wimpy battery or starter near death, you hear a click then nothing.

Can you turn it by hand now?

[leadrsa729]

Hi -

No oddities experienced during the initial spin up. I did 30 seconds, let the starter cool down, then another 30 sec, let it cool down, then 15 secs after that. Everything seemed fine. I would have connected the coil then and there, but I noticed a leak from the fuel pump that I pulled out and had fixed.

The plugs were and are definitely in. Its tight, but I can turn it by hand with some effort. I'm sure it would be a lot easier to turn with the plugs out. I was spinning it by hand constantly when I set the cam timing, and that was not difficult by any means.

[Bob Kontak]

Originally Posted by leadrsa729

Its tight, but I can turn it by hand with some effort. I'm sure it would be a lot easier to turn with the plugs out.

I would take the plugs out and try.

I am just talking. I have not experienced this.

What did you do to the engine?

Sixty seconds on an old starter with compression may have put it to bed. Any smell?

Battery negative lead to ground?

[T77911S]

check the battery connections first. clean them. make sure the battery to body connection is good along with the body to tranny connection, you may have forgotten to connect it.

make sure the battery is fully charged and check batt volt when cranking. if below 10v have it tested/replaced

[yelcab1]

Definitely strange. It's time to go back to basic.

Remove plugs, turn over by hand, it should see very little resistance and give it a chance to clear out any vapor lock

Install plugs, clean battery terminals, ensure all ground straps are tight

Put a volt meter across the battery and start the car. See what the battery voltage drops to. If it drops to below 10V, your battery is bad. Otherwise, the engine should turn over. IF not, your starter is bad.

[Hnichols]

Originally Posted by leadrsa729

Hi -

No oddities experienced during the initial spin up. I did 30 seconds, let the starter cool down, then another 30 sec, let it cool down, then 15 secs after that. Everything seemed fine. I would have connected the coil then and there, but I noticed a leak from the fuel pump that I pulled out and had fixed.

I think I'm with Bob on this one, if you mean a literal 30 seconds. 30 literal seconds seems like an eternity to me cranking an old engine. But maybe you actually were cranking for about 8 seconds at a time (?).

[pmax]

Did you flood a cylinder ?

Take the plugs out.

[leadrsa729]

Hi Hnichols -

I see you're close by! I was just following the instructions in Wayne's engine rebuild book in Chapter 6 on the break-in procedure I should follow.

I've ordered a new Optima PC925 battery that should be arriving today. I'll be sure to post the results. Hopefully I didn't burn up my starter!

Thanks everyone!

[Bob Kontak]

Originally Posted by leadrsa729

Hopefully I didn't burn up my starter!

Far from the worst scenario.

Do check the cables and grounds.

[leadrsa729]

Success! Battery did indeed come today. I installed it, made sure all connections were good and clean, and checked my grounds.

Engine turned over as it should. Thanks again to all who contributed!

[Bob Kontak]

Originally Posted by leadrsa729

Engine turned over as it should.

Sweet!

Bet you sleep well tonight.

The starter buzzing was a new one for me.