620 LP Starter

[Scott Sackett]

I"m fortunate that my 620 LP starts quite easily. The problem is getting the starter to turn over fast enough. Like one gentleman said, "if I pull this tractor 6 feet, it starts quickly and easily". I can"t imagine that my starter turned over this slowly when the tractor was new. Even with a new 750 cranking amp 12 volt deep cell battery the starter turns over like the battery was nearly dead. Does anyone have this problem or a suggestion? Thanks in advance.

 

[730d se]

You can buy a kit to rebuild the starter. The kits are simple and include new brushes, new bushings, etc.
If you have a an old generator/starter shop near by, you may want to have them check it.

 

[Gerald Bennett]

Hi Scott,
I have a 70lp and a 630lp, both start good. You might try heaver battery cables and make sure the ends very tight, and use a braded ground strap.
I hope this might help, just a thought.
Gerald

 

[Scott Sackett]

Thank you very much for your comments.

 

[Scott Sackett]

Thanks very much

 

[buickanddeere]

Your tractor has VD.
Cranking rpm doesn't matter on a spark ignition engine.On diesels it's everything but people mix them up.
Ignition coil voltage does matter. That's why the engine starts when pulled, it has spark. When cranking there is an electrical fault(s) which lowers the voltage to the coil below what is required to spark the plug.
Another thing to check besides the conditions of the bypass starting circuit and too small of a battery. Odds are somebody installed the coil with reverse polarity which reduces spark voltage.
I'll bet when the seat is lifted there is not a 1000CCA group 31 battery under there. And a cable from Walmart is running from the battery to the battery box. The chassis return cable needs to be longer/heavier and bolted to cast iton, not rusty sheet metal.

 

[Scott Sackett]

Dear buickanddeere,

Thanks a bunch for your thoughts. I'm getting plenty of spark and my engine starts. My question revolves largely around the starter rpm. I think your electrical comments are right on the money. Regarding 1000CCA, I'm a bit confused about that. When these tractors came out they had to 6 volt batteries hooked together with only about 400CCA. I've got a new deep cell with 750CCA and the rpm on the starter are just slower than you can imagine. When I talk to the old timers they don't remember a starter turning over this slow. I'm guessing it turns over about once per second. I'm using a 20/0 cable to the starter and a webbed ground (to a cleaned, not rusted seat). I'll try going to the block or cast iron. I'm fortunate that the tractor does start relatively easy I guess. I'm just searching for the missing clues on the starter very very slow starting rpm. Thanks again for your ideas.

Best regards,
Scott

 

[TractormanNC]

In two of your posts you said "deep cell" battery. Are you meaning "DEEP CYCLE"? If so, that may very well be the problem, deep cycle batteries were NOT designed for starting where you need a lot of amps in a short burst for starting. deep cycle batteries are designed to power low amp loads for a long time.
As B&D says put a 1000 CCA group 31 and good heavy cables on it and see what she does.

 

[Scott Sackett]

Thanks Tractorman. I'm trying everything.

 

[Scott Sackett]

Here's a thought. I did some checking and found out that back in the day these tractors came new with two 6 volt batteries hooked together. These two together produced only about 400CCA. If everything is as it should be, I'm not sure why I'd need 1000CCA. What are your thoughts on this?

Thanks