Weak Crank - won't start

[awesomesteven]

I'm having issues with the boat starting up ('86 supra 351w). When I turn the key the engine cranks like it has a weak battery and won't start. I have a new battery and its reading at 12.54 v. However, when the key is turned the voltage drops to around 9.5v.

Is this a bad starter or possibly a dead cell in the battery? Are there other tests I can perform with multimeter to rule out one or the other?

(I can't take them to get tested until tomorrow so this is more of a learning exercise - as I guess pretty much everything I've done so far)

If it does end up being a bad starter, has anyone bought a starter off db-electrical? Are they good quality?
http://www.dbelectrical.com/p-5917-new-crusader-ford-mercruiser-starter-ford-engines.aspx

[wspeedin]

I have had the same issue. Turned out to be a bad starter. I know on the 454 the starter is rebuildable but not sure on the 351W.

[wotan2525]

I've always had good luck with the db electrical stuff. Usually cheaper than the rebuild that I can get locally....

[Jetlink]

Steven, are you just checking the voltage with a multimeter or are you using a battery tester? The battery tester places a load on the battery and actually works the battery whereas the multimeter won't really be able to do that.

[awesomesteven]

Steven, are you just checking the voltage with a multimeter or are you using a battery tester? The battery tester places a load on the battery and actually works the battery whereas the multimeter won't really be able to do that.

I did this with a multimeter. I don't have a battery tester.

[rideevol]

To find a voltage drop area take several multimeter measurements. I work from the battery and outward.
Start at battery post to post for baseline. Two persons on these tests is safer. In your instance if post-to-post shows 9.5 volt during crank you either need a battery charge or a replacement battery, 9.5 is a bit low during cranking.
Next step is + post to + battery clamp/cable terminal, yep on top of the battery. A little corrosion can do a lot of harm at this area. You should only see a tiny voltage drop, a few tenths of a volt. Follow the + cable outward in this manner.
The negative battery cable can also contribute a voltage drop so working outward from the battery post there as well. If it is cable or connection related, this is the method.

[awesomesteven]

Thanks for the step by step rideevol. I'll have to give that a shot when I get back.

BTW, was that the correct starter I had on the link or does the sunsport need a ccw starter?

[CornRickey]

If you have electronic conversion ignition a weak battery or bad starter taking to many amps won't allow enough energy to the ignition allowing it to trigger. Petronix needs 9 volts if I remember right. Rebuilt starters and alts are usually better than new, non-oem stuff. They tend to use better components. My local guy says his stuff is better than factory and I believe him.

[awesomesteven]

Rebuilt starters and alts are usually better than new, non-oem stuff. They tend to use better components. My local guy says his stuff is better than factory and I believe him.

That's interesting! I might start looking for a local guy if it turns out my starter is bad.

[rideevol]

My experience with local has been great. Took my 51 amp alternator to a local guy and it was returned, tested, with no needed rebuild, and no charge. If you find a local starter shop they will have all the specialized gear to test starters.
Two starter types were used up to 1986 on Ford engines, Delco_Remy and Ford. Reference Service manual PCM_engine_svcmanual 335 pages on site correctcraftfan.com This manual covers up to April 1986 if my memory is correct.

[awesomesteven]

Update-

Both the starter and the battery tested out well. It must be one of my connections somewhere. Time to go through all of them again.

There was one odd thing with the starter. If you had the starter so the bendix gear was pointing down and then flipped it so it was pointing up, it seemed like the entire inside was loose. I know you can manually move the bendix gear up and down by turning it, but this was the entire inside parts were shifting just a bit. I ended up picking up a new one (for $50! - kept my old one) and the guy at the parts store told me that if the new starter doesn't solve the issue I could just return it. How nice is that!

[CornRickey]

real nice until you return it and the guy isn't there. ;)